Persistent storage using logical volume manager storage

Logical Volume Manager (LVM) Storage uses LVM2 through the TopoLVM CSI driver to dynamically provision local storage on a cluster with limited resources. With LVM Storage, you can create volume groups, persistent volume claims (PVCs), snapshots, and clones.

Logical Volume Manager Storage installation

You can install LVM Storage on an OpenShift Container Platform cluster and configure it to dynamically provision storage for your workloads.

You can install LVM Storage by using the OpenShift Container Platform CLI (oc), OpenShift Container Platform web console, or Red Hat Advanced Cluster Management (RHACM).

Warning

When using LVM Storage on multi-node clusters, LVM Storage only supports provisioning local storage. LVM Storage does not support storage data replication mechanisms across nodes. You must ensure storage data replication through active or passive replication mechanisms to avoid a single point of failure.

Prerequisites to install LVM Storage

The prerequisites to install LVM Storage are as follows:

• Ensure that you have a minimum of 10 milliCPU and 100 MiB of RAM.

• Ensure that every managed cluster has dedicated disks that are used to provision storage. LVM Storage uses only those disks that are empty and do not contain file system signatures. To ensure that the disks are empty and do not contain file system signatures, wipe the disks before using them.

• Before installing LVM Storage in a private CI environment where you can reuse the storage devices that you configured in the previous LVM Storage installation, ensure that you have wiped the disks that are not in use. If you do not wipe the disks before installing LVM Storage, you cannot reuse the disks without manual intervention.

  Note

  You cannot wipe the disks that are in use.

• If you want to install LVM Storage by using Red Hat Advanced Cluster Management (RHACM), ensure that you have installed RHACM on an OpenShift Container Platform cluster. For more information, see "Installing LVM Storage by using RHACM".

Installing LVM Storage by using the CLI

You can install LVM Storage by using the OpenShift CLI (oc) to dynamically provision local storage on clusters with limited resources.

Note

The default namespace for the LVM Storage Operator is openshift-lvm-storage.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to OpenShift Container Platform as a user with cluster-admin and Operator installation permissions.

Procedure

1. Create a YAML file with the configuration for creating a namespace:

   Example YAML configuration for creating a namespace

   apiVersion: v1
   kind: Namespace
   metadata:
     labels:
       openshift.io/cluster-monitoring: "true"
       pod-security.kubernetes.io/enforce: privileged
       pod-security.kubernetes.io/audit: privileged
       pod-security.kubernetes.io/warn: privileged
     name: openshift-lvm-storage
   

2. Create the namespace by running the following command:

   $ oc create -f <file_name>
   

3. Create an OperatorGroup CR YAML file:

   Example OperatorGroup CR

   apiVersion: operators.coreos.com/v1
   kind: OperatorGroup
   metadata:
     name: openshift-storage-operatorgroup
     namespace: openshift-lvm-storage
   spec:
     targetNamespaces:
     - openshift-storage
   

4. Create the OperatorGroup CR by running the following command:

   $ oc create -f <file_name> 
   

5. Create a Subscription CR YAML file:

   Example Subscription CR

   apiVersion: operators.coreos.com/v1alpha1
   kind: Subscription
   metadata:
     name: lvms
     namespace: openshift-lvm-storage
   spec:
     installPlanApproval: Automatic
     name: lvms-operator
     source: redhat-operators
     sourceNamespace: openshift-marketplace
   

6. Create the Subscription CR by running the following command:

   $ oc create -f <file_name> 
   

Verification

1. To verify that LVM Storage is installed, run the following command:

   $ oc get csv -n openshift-lvm-storage -o custom-columns=Name:.metadata.name,Phase:.status.phase
   

   Example output

   Name                         Phase
   4.13.0-202301261535          Succeeded
   

Installing LVM Storage by using the web console

Install LVM Storage from the OpenShift Container Platform web console to dynamically provision local storage on clusters with limited resources.

Note

The default namespace for the LVM Storage Operator is openshift-lvm-storage.

Prerequisites

• You have access to the cluster.
• You have access to OpenShift Container Platform with cluster-admin and Operator installation permissions.

Procedure

1. Log in to the OpenShift Container Platform web console.

2. Click Ecosystem → Software Catalog.

3. Click LVM Storage on the software catalog page.

4. Set the following options on the Operator Installation page:

   1. Update Channel as stable-4.22.

   2. Installation Mode as A specific namespace on the cluster.

   3. Installed Namespace as Operator recommended namespace openshift-storage. If the openshift-lvm-storage namespace does not exist, it is created during the operator installation.

   4. Update approval as Automatic or Manual.

      Note

      If you select Automatic updates, the Operator Lifecycle Manager (OLM) automatically updates the running instance of LVM Storage without any intervention.

      If you select Manual updates, the OLM creates an update request. As a cluster administrator, you must manually approve the update request to update LVM Storage to a newer version.

5. Optional: Select the Enable Operator recommended cluster monitoring on this Namespace checkbox.

6. Click Install.

Verification

• Verify that LVM Storage shows a green tick, indicating successful installation.

Installing LVM Storage in a disconnected environment

Install LVM Storage in a disconnected environment where your cluster has no internet access, such as air-gapped networks, high-security facilities, or regulated industries requiring network isolation for security and compliance.

Prerequisites

• You read "About disconnected installation mirroring".
• You have access to the OpenShift Container Platform image repository.
• You created a mirror registry (see "Creating a mirror registry with mirror registry for Red Hat OpenShift").

Procedure

1. Follow the steps in the "Creating the image set configuration" procedure. To create an ImageSetConfiguration custom resource (CR) for LVM Storage, you can use the following example ImageSetConfiguration CR configuration:

   Example ImageSetConfiguration CR for LVM Storage

   kind: ImageSetConfiguration
   apiVersion: mirror.openshift.io/v1alpha2
   archiveSize: 4
   storageConfig:
     registry:
       imageURL: example.com/mirror/oc-mirror-metadata
       skipTLS: false
   mirror:
     platform:
       channels:
       - name: stable-4.22
         type: ocp
       graph: true
     operators:
     - catalog: registry.redhat.io/redhat/redhat-operator-index:v4.22
       packages:
       - name: lvms-operator
         channels:
         - name: stable
     additionalImages:
     - name: registry.redhat.io/ubi9/ubi:latest
     helm: {}
   

   • archiveSize: Specifies the maximum size (in GiB) of each file within the image set.
   • storageConfig: Specifies the location in which you want to save the image set. This location can be a registry or a local directory. You must configure the storageConfig field unless you are using the Technology Preview OCI feature.
   • storageConfig.registry.imageURL: Specifies the storage URL for the image stream when using a registry. For more information, see "Why use imagestreams".
   • mirror.platform.name: Specifies the channel from which you want to retrieve the OpenShift Container Platform images.
   • mirror.platform.channels[].name: Set this field to true to generate the OpenShift Update Service (OSUS) graph image. For more information, see "About the OpenShift Update Service".
   • mirror.operators.catalog: Specifies the Operator catalog from which you want to retrieve the OpenShift Container Platform images.
   • mirror.operators.packages.name: Specifies the Operator packages to include in the image set. If this field is empty, all packages in the catalog are retrieved.
   • mirror.operators[].packages[].channels.name: Specifies the channels of the Operator packages to include in the image set. You must include the default channel for the Operator package even if you do not use the bundles in that channel. You can find the default channel by running the following command: $ oc mirror list operators --catalog=<catalog_name> --package=<package_name>.
   • mirror.additionalImages.name: Specifies any additional images to include in the image set.

2. Follow the procedure in "Mirroring an image set to a mirror registry".

3. Follow the procedure in "Configuring image registry repository mirroring".

Additional resources

• About disconnected installation mirroring
• Mirroring the OpenShift Container Platform image repository
• Creating the image set configuration
• Mirroring an image set to a mirror registry
• Configuring image registry repository mirroring
• Why use imagestreams
• About the OpenShift Update Service

Installing LVM Storage by using RHACM

To install LVM Storage on clusters by using Red Hat Advanced Cluster Management (RHACM), you must create a Policy custom resource (CR) and configure the criteria to select the target clusters.

Note

The Policy CR that is created to install LVM Storage is also applied to the clusters that are imported or created after creating the Policy CR.

Prerequisites

• You have access to the RHACM cluster using an account with cluster-admin and Operator installation permissions.
• You have dedicated disks that LVM Storage can use on each cluster.
• The cluster must be managed by RHACM.

Procedure

1. Log in to the RHACM CLI using your OpenShift Container Platform credentials.

2. Create a namespace.

   $ oc create ns <namespace>
   

3. Create a Policy CR YAML file:

   Example Policy CR to install and configure LVM Storage

   apiVersion: apps.open-cluster-management.io/v1
   kind: PlacementRule
   metadata:
     name: placement-install-lvms
   spec:
     clusterConditions:
     - status: "True"
       type: ManagedClusterConditionAvailable
     clusterSelector:
       matchExpressions:
       - key: mykey
         operator: In
         values:
         - myvalue
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: PlacementBinding
   metadata:
     name: binding-install-lvms
   placementRef:
     apiGroup: apps.open-cluster-management.io
     kind: PlacementRule
     name: placement-install-lvms
   subjects:
   - apiGroup: policy.open-cluster-management.io
     kind: Policy
     name: install-lvms
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: Policy
   metadata:
     annotations:
       policy.open-cluster-management.io/categories: CM Configuration Management
       policy.open-cluster-management.io/controls: CM-2 Baseline Configuration
       policy.open-cluster-management.io/standards: NIST SP 800-53
     name: install-lvms
   spec:
     disabled: false
     remediationAction: enforce
     policy-templates:
     - objectDefinition:
         apiVersion: policy.open-cluster-management.io/v1
         kind: ConfigurationPolicy
         metadata:
           name: install-lvms
         spec:
           object-templates:
           - complianceType: musthave
             objectDefinition:
               apiVersion: v1
               kind: Namespace
               metadata:
                 labels:
                   openshift.io/cluster-monitoring: "true"
                   pod-security.kubernetes.io/enforce: privileged
                   pod-security.kubernetes.io/audit: privileged
                   pod-security.kubernetes.io/warn: privileged
                 name: openshift-lvm-storage
           - complianceType: musthave
             objectDefinition:
               apiVersion: operators.coreos.com/v1
               kind: OperatorGroup
               metadata:
                 name: openshift-storage-operatorgroup
                 namespace: openshift-lvm-storage
               spec:
                 targetNamespaces:
                 - openshift-lvm-storage
           - complianceType: musthave
             objectDefinition:
               apiVersion: operators.coreos.com/v1alpha1
               kind: Subscription
               metadata:
                 name: lvms
                 namespace: openshift-lvm-storage
               spec:
                 installPlanApproval: Automatic
                 name: lvms-operator
                 source: redhat-operators
                 sourceNamespace: openshift-marketplace
           remediationAction: enforce
           severity: low
   

   • spec.clusterSelector: Set the key field and values field in PlacementRule.spec.clusterSelector to match the labels that are configured in the clusters on which you want to install LVM Storage.
   • spec.policy-templates[0].objectDefinition[0].spec.object-templates[0].objectDefinition: Specifies the namespace configuration.
   • spec.policy-templates[0].objectDefinition[1].spec.object-templates[1].objectDefinition: Specifies the OperatorGroup CR configuration.
   • spec.policy-templates[0].objectDefinition.spec.object-templates[2].objectDefinition:Specifies the Subscription CR configuration.

4. Create the Policy CR by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

   Upon creating the Policy CR, the following custom resources are created on the clusters that match the selection criteria configured in the PlacementRule CR:

   • Namespace

   • OperatorGroup

   • Subscription

     Note

     The default namespace for the LVM Storage Operator is openshift-lvm-storage.

Additional resources

• About the LVMCluster custom resource

Static and dynamic device discovery in LVM Storage

You can use static or dynamic discovery policies to manage how block devices join your volume groups. Selecting the appropriate policy helps you automate storage expansion safely or preserve a locked, predictable storage footprint over time.

Static

The Operator creates the volume group by using devices it finds at installation time. The Operator ignores devices discovered after the volume group exists.

Static discovery is the default policy for new volume groups. It eliminates operational risk by locking the device set after the Operator creates the volume group.

Combined with explicit device paths, it provides a fully deterministic storage configuration.

Without explicit paths, the Operator discovers devices only at creation time and then stops the set.

Dynamic

The Operator continuously discovers and adds devices to the volume group on each reconciliation cycle.

Dynamic discovery remains the default for existing volume groups where the policy field is nil to maintain backward compatibility.

However, this policy can lead to unexpected behavior in production environments. Devices that appear after the initial setup because of hardware changes, driver reloads, or kernel device renaming are automatically added to the volume group.

This creates operational risk because the volume group composition becomes non-deterministic and depends on the runtime state of the node rather than explicit administrator intent.

Note

The Operator adds the DeviceDiscoveryPolicy field to the DeviceClass specification. If you explicitly set device paths in deviceSelector.paths or deviceSelector.optionalPaths, the cluster always uses those exact paths, and ignores your discovery policy setting.

The cluster status reports the effective policy by using DeviceDiscoveryPolicyStatus, which distinguishes three runtime states:

Effective policy status values

Status value	Description
Preconfigured	Explicit device paths configuration by using deviceSelector. Discovery policy is not applicable.
RuntimeDynamic	No explicit paths. Discovery policy is Dynamic. The Operator continuously discovers devices.
RuntimeStatic	No explicit paths. Discovery policy is Static. The Operator discovers devices once at creation time.

The following table shows the behavior matrix:

Device discovery behavior by configuration

Explicit paths	Discovery policy	Effective behavior
Yes	Any / nil	Preconfigured: The Operator honors the specified paths and ignores the discovery policy.
No	Static	RuntimeStatic: The Operator locks the device set immediately after creating the volume group
No	Dynamic	RuntimeDynamic: continuous discovery every 30 seconds
No	nil (new volume group)	RuntimeStatic: defaults to Static
No	nil (existing volume group)	RuntimeDynamic: defaults to Dynamic for backward compatibility

Static mode enforcement

In static mode, the system locks the device set after initial discovery. If a volume group lacks explicit paths, newly attached devices are automatically excluded to prevent unintended volume expansions.

This strict filtering behavior does not apply during the very first reconciliation cycle. During this initial pass, the Operator discovers all available devices to successfully create the volume group. Once created, the Operator locks the device set during all subsequent reconciliations.

The discovery policy also controls whether the controller re-queues for periodic device scanning:

Requeue behavior by configuration

Configuration	Periodic requeue
Explicit paths	No: paths define the exact device set; changes trigger reconciliation by using the LVMVolumeGroup watch
Dynamic without explicit paths	Yes: every 30 seconds
Static without explicit paths	No: device set is locked after creation

Validation rules for device discovery policy

To ensure your storage cluster deploys successfully and avoids misconfiguration errors, the validating webhook enforces strict rules when you create or update an LVMCluster custom resource.

Creation

• If you define one device class without paths, a webhook warning appears. Avoid the default Static policy in production. Set deviceDiscoveryPolicy explicitly.
• If multiple device classes are defined, every device class must specify device paths. Auto-discovery without paths is not allowed with many device classes. The cluster cannot determine which devices belong to which class.
• If the deviceDiscoveryPolicy is empty and paths are missing, a webhook warning appears. Administrators must define the policy explicitly.

Updates

No specific update restrictions apply to the deviceDiscoveryPolicy field. You can change it at any time.

The following table shows how the device discovery policy feature interacts with other features:

Device discovery policy feature interactions

Feature	Interaction
forceWipeDevicesAndDestroyAllData	Works independently of the discovery policy. Devices are wiped before being added to the volume group, regardless of how they were discovered.
Node selector	Works independently. The discovery policy applies only to the set of devices found on nodes matching the selector.

LVMCluster custom resource examples

You can configure the deviceDiscoveryPolicy field in your LVMCluster custom resource (CR) by using these examples to meet your specific storage requirements.

Explicit device paths (recommended for production)

yaml apiVersion: lvm.topolvm.io/v1alpha1 kind: LVMCluster metadata: name: my-lvmcluster spec: storage: deviceClasses: - name: vg1 deviceSelector: paths: - /dev/disk/by-id/scsi-SATA_VBOX_HARDDISK_VB12345678-90abcdef - /dev/disk/by-id/scsi-SATA_VBOX_HARDDISK_VBabcdef01-23456789 thinPoolConfig: name: thin-pool-1 sizePercent: 90

The discovery policy is not relevant here. Explicit paths always define the device set.

Static discovery without explicit paths

yaml apiVersion: lvm.topolvm.io/v1alpha1 kind: LVMCluster metadata: name: my-lvmcluster spec: storage: deviceClasses: - name: vg1 deviceDiscoveryPolicy: Static thinPoolConfig: name: thin-pool-1 sizePercent: 90

The Operator discovers and adds all available devices to the volume group during the initial reconciliation. After the Operator creates the volume group, it adds no new devices.

Dynamic discovery without explicit paths (not recommended for production)

yaml apiVersion: lvm.topolvm.io/v1alpha1 kind: LVMCluster metadata: name: my-lvmcluster spec: storage: deviceClasses: - name: vg1 deviceDiscoveryPolicy: Dynamic thinPoolConfig: name: thin-pool-1 sizePercent: 90

The Operator continuously discovers and adds devices to the volume group every 30 seconds. This setting is useful for development and testing. However, it might introduce operational risks in production environments.

LVM cluster custom resource status reporting

To view a list of excluded devices and the reason for their exclusion, use the LVMVolumeGroupNodeStatus custom resource (CR).

If static device discovery excludes a device, the status report displays the error in the following format:

<device> was not part of <vg_name> at creation (static device discovery enabled)

The VGStatus.DeviceDiscoveryPolicy parameter reports the effective discovery policy as one of the following values:

• Preconfigured
• RuntimeDynamic
• RuntimeStatic.

About the LVMCluster custom resource

The LVMCluster custom resource (CR) is the primary configuration for LVM Storage deployment, defining how storage is provisioned across your cluster by specifying volume groups, devices, node selection, and thin pool settings to meet your workload requirements.

You can configure the LVMCluster CR to perform the following actions:

• Create LVM volume groups that you can use to provision persistent volume claims (PVCs).
• Configure a list of devices that you want to add to the LVM volume groups.
• Configure the requirements to select the nodes on which you want to create an LVM volume group, and the thin pool configuration for the volume group.
• Force wipe the selected devices.

After you have installed LVM Storage, you must create an LVMCluster custom resource (CR).

Example LVMCluster CR YAML file

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
spec:
  tolerations:
  - effect: NoSchedule
    key: xyz
    operator: Equal
    value: "true"
  storage:
    deviceClasses: 
    - name: vg1  
      fstype: ext4
      default: true 
      nodeSelector:
        nodeSelectorTerms: 
        - matchExpressions:
          - key: mykey
            operator: In
            values:
            - ssd
      deviceSelector:
        paths: 
        - /dev/disk/by-path/pci-0000:87:00.0-nvme-1
        - /dev/disk/by-path/pci-0000:88:00.0-nvme-1
        optionalPaths:
        - /dev/disk/by-path/pci-0000:89:00.0-nvme-1
        - /dev/disk/by-path/pci-0000:90:00.0-nvme-1
        forceWipeDevicesAndDestroyAllData: true
      thinPoolConfig: 
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10 
        chunkSize: 128Ki
        chunkSizeCalculationPolicy: Static
        metadataSize: 1Gi
        metadataSizeCalculationPolicy: Host

The following are optional fields: fstype, nodeSelector, deviceSelector, sizePercent, chunkSize, chunkSizeCalculationPolicy, metadataSize,metadataSizeCalculationPolicy.

Explanation of fields in the LVMCluster CR

The LVMCluster CR fields are described in the following table:

LVMCluster CR fields

Field	Type	Description
spec.storage.deviceClasses	array	Contains the configuration to assign the local storage devices to the LVM volume groups. LVM Storage creates a storage class and volume snapshot class for each device class that you create.
deviceClasses.name	string	Specify a name for the LVM volume group (VG). You can also configure this field to reuse a volume group that you created in the previous installation. For more information, see "Reusing a volume group from the previous LVM Storage installation".
deviceClasses.fstype	string	Set this field to ext4 or xfs. By default, this field is set to xfs.
deviceClasses.default	boolean	Set this field to true to indicate that a device class is the default. Otherwise, you can set it to false. You can only configure a single default device class.
deviceClasses.nodeSelector	object	Contains the configuration to choose the nodes on which you want to create the LVM volume group. If this field is empty, all nodes without no-schedule taints are considered. On the control-plane node, LVM Storage detects and uses the additional worker nodes when the new nodes become active in the cluster.
nodeSelector.nodeSelectorTerms	array	Configure the requirements that are used to select the node.
deviceClasses.deviceSelector	object	Contains the configuration to perform the following actions: Specify the paths to the devices that you want to add to the LVM volume group. Force wipe the devices that are added to the LVM volume group. For more information, see "About adding devices to a volume group".
deviceSelector.paths	array	Specify the device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, the LVMCluster CR moves to the Failed state.
deviceSelector.optionalPaths	array	Specify the optional device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, LVM Storage ignores the device without causing an error.
deviceSelector. forceWipeDevicesAndDestroyAllData	boolean	LVM Storage uses only those disks that are empty and do not contain file system signatures. To ensure that the disks are empty and do not contain file system signatures, wipe the disks before using them. To force wipe the selected devices, set this field to true. By default, this field is set to false. Warning If this field is set to true, LVM Storage wipes all previous data on the devices. Use this feature with caution. Wiping the device can lead to inconsistencies in data integrity if any of the following conditions are met: The device is being used as swap space. The device is part of a RAID array. The device is mounted. If any of these conditions are true, do not force wipe the disk. Instead, you must manually wipe the disk.
deviceClasses.storageClassOptions	object	Optional. Allows customization of the StorageClass created for this device class, including reclaim policy, volume binding mode, additional parameters, and labels. For more information, see "StorageClass customization for LVMS device classes".
deviceClasses.thinPoolConfig	object	Contains the configuration to create a thin pool in the LVM volume group. If you exclude this field, logical volumes are thick provisioned. Using thick-provisioned storage includes the following limitations: No copy-on-write support for volume cloning. No support for snapshot class. No support for over-provisioning. As a result, the provisioned capacity of PersistentVolumeClaims (PVCs) is immediately reduced from the volume group. No support for thin metrics. Thick-provisioned devices only support volume group metrics.
thinPoolConfig.name	string	Specify a name for the thin pool.
thinPoolConfig.sizePercent	integer	Specify the percentage of space in the LVM volume group for creating the thin pool. By default, this field is set to 90. The minimum value that you can set is 10, and the maximum value is 90.
thinPoolConfig.overprovisionRatio	integer	Specify a factor by which you can provision additional storage based on the available storage in the thin pool. For example, if this field is set to 10, you can provision up to 10 times the amount of available storage in the thin pool. You can modify this field after the LVM cluster has been created. To update the parameter, do any of the following tasks: To edit the LVM Cluster, run the following command: $ oc edit lvmcluster <lvmcluster_name> To apply a patch, run the following command: $ oc patch lvmcluster <lvmcluster_name> -p <patch_file.yaml> To disable over-provisioning, set this field to 1.
thinPoolConfig.chunkSize	integer	Specifies the statically calculated chunk size for the thin pool. This field is only used when the ChunkSizeCalculationPolicy field is set to Static. The value for this field must be configured in the range of 64 KiB to 1 GiB because of the underlying limitations of lvm2. If you do not configure this field and the ChunkSizeCalculationPolicy field is set to Static, the default chunk size is set to 128 KiB. For more information, see "Overview of chunk size".
thinPoolConfig.chunkSizeCalculationPolicy	string	Specifies the policy to calculate the chunk size for the underlying volume group. You can set this field to either Static or Host. By default, this field is set to Static. If this field is set to Static, the chunk size is set to the value of the chunkSize field. If the chunkSize field is not configured, chunk size is set to 128 KiB. If this field is set to Host, the chunk size is calculated based on the configuration in the lvm.conf file. For more information, see "Limitations to configure the size of the devices used in LVM Storage".
thinPoolConfig.metadataSize	integer	Specifies the metadata size for the thin pool. You can configure this field only when the MetadataSizeCalculationPolicy field is set to Static. If this field is not configured, and the MetadataSizeCalculationPolicy field is set to Static, the default metadata size is set to 1 GiB. The value for this field must be configured in the range of 2 MiB to 16 GiB due to the underlying limitations of lvm2. You can only increase the value of this field during updates.
thinPoolConfig.metadataSizeCalculationPolicy	string	Specifies the policy to calculate the metadata size for the underlying volume group. You can set this field to either Static or Host. By default, this field is set to Host. If this field is set to Static, the metadata size is calculated based on the value of the thinPoolConfig.metadataSize field. If this field is set to Host, the metadata size is calculated based on the lvm2 settings.

Additional resources

• Overview of chunk size
• Limitations to configure the size of the devices used in LVM Storage
• Reusing a volume group from the previous LVM Storage installation
• About adding devices to a volume group
• Adding worker nodes to single-node OpenShift clusters

Limitations to configure the size of the devices used in LVM Storage

To ensure your devices are compatible with storage operations, review the size configuration limitations in LVM Storage. Adhering to these constraints prevents provisioning failures by ensuring selected devices meet the required capacity specifications.

When provisioning storage by using LVM Storage, the following factors limit device size:

• The total storage size that you can provision is limited by the size of the underlying Logical Volume Manager (LVM) thin pool and the over-provisioning factor.

• The size of the logical volume depends on the size of the Physical Extent (PE) and the Logical Extent (LE).

  • You can define the size of PE and LE during the physical and logical device creation.
  • The default PE and LE size is 4 MiB.
  • If the size of the PE is increased, the maximum size of the LVM is determined by the kernel limits and your disk space.

The following tables describe the chunk size and volume size limits for static and host configurations:

Tested configuration

Parameter	Value
Chunk size	128 KiB
Maximum volume size	32 TiB

Theoretical size limits for static configuration

Parameter	Minimum value	Maximum value
Chunk size	64 KiB	1 GiB
Volume size	Minimum size of the underlying Red Hat Enterprise Linux CoreOS (RHCOS) system.	Maximum size of the underlying RHCOS system.

Theoretical size limits for a host configuration

Parameter	Value
Chunk size	This value is based on the configuration in the lvm.conf file. By default, the configuration sets the value to 128 KiB.
Maximum volume size	Equal to the maximum volume size of the underlying RHCOS system.
Minimum volume size	Equal to the minimum volume size of the underlying RHCOS system.

About adding devices to a volume group

To add devices to the Logical Volume Manager (LVM) volume group, use the deviceSelector field in the LVMCluster Custom Resource (CR) to specify the paths to the devices.

You can specify the device paths in the deviceSelector.paths field, the deviceSelector.optionalPaths field, or both. If you do not specify the device paths in both the deviceSelector.paths field and the deviceSelector.optionalPaths field, LVM Storage adds the supported unused devices to the volume group (VG).

Warning

It is recommended to avoid referencing disks using symbolic naming, such as /dev/sdX, as these names may change across reboots within RHCOS. Instead, you must use stable naming schemes, such as /dev/disk/by-path/ or /dev/disk/by-id/, to ensure consistent disk identification.

With this change, you might need to adjust existing automation workflows in the cases where monitoring collects information about the install device for each node.

For more information, see the "RHEL documentation".

You can add the path to the Redundant Array of Independent Disks (RAID) arrays in the deviceSelector field to integrate the RAID arrays with LVM Storage. You can create the RAID array by using the mdadm utility. LVM Storage does not support creating a software RAID.

Note

You can create a RAID array only during an OpenShift Container Platform installation. For information on creating a RAID array, see:

• "Configuring a RAID-enabled data volume"
• "Creating a software RAID on an installed system"
• "Replacing a failed disk in RAID"
• "Repairing RAID disks"

You can also add encrypted devices to the volume group. You can enable disk encryption on the cluster nodes during an OpenShift Container Platform installation. After encrypting a device, you can specify the path to the LUKS encrypted device in the deviceSelector field. For information on disk encryption, see "About disk encryption" and "Configuring disk encryption and mirroring".

The devices that you want to add to the VG must be supported by LVM Storage. For information about unsupported devices, see "Devices not supported by LVM Storage".

LVM Storage adds the devices to the VG only if the following conditions are met:

• The device path exists.
• The device is supported by LVM Storage.

Warning

After a device is added to the VG, you cannot remove the device.

LVM Storage supports dynamic device discovery. If you do not add the deviceSelector field in the LVMCluster CR, LVM Storage automatically adds the new devices to the VG when the devices are available.

Warning

It is not recommended to add the devices to the VG through dynamic device discovery due to the following reasons:

• When you add a new device that you do not intend to add to the VG, LVM Storage automatically adds this device to the VG through dynamic device discovery.
• If LVM Storage adds a device to the VG through dynamic device discovery, LVM Storage does not restrict you from removing the device from the node. Removing or updating the devices that are already added to the VG can disrupt the VG. This can also lead to data loss and necessitate manual node remediation.

Additional resources

• RHEL documentation
• Creating a software RAID on an installed system
• Replacing a failed disk in RAID
• Repairing RAID disks
• Configuring a RAID-enabled data volume
• About disk encryption
• Configuring disk encryption and mirroring
• Devices not supported by LVM Storage

About removing devices and device classes from a volume group

You can remove devices and device classes from a Logical Volume Manager (LVM) volume group to decommission storage hardware or reorganize your storage configuration by updating the deviceSelector field in the LVMCluster CR.

Removing the device paths in the deviceSelector.paths field

You can remove the device paths in the deviceSelector.paths field.

Warning

Ensure that the following criteria are met before removing device paths:

• The device that you want to remove is empty. You can use the pvdisplay command to see attributes of physical volumes (PVs) used in LVM.
• At least one additional device is specified in the deviceSelector.paths field.

Removing the deviceClass from the LVMCluster

You can also remove the deviceClass object from the LVMCluster resource. For device class deletion, there is no need to delete deviceSelector.paths object.

Warning

Ensure that the following criteria are met before removing a device class:

• The deviceClasses.default field is set to false.
• The disks specified in the deviceSelector.paths field are empty.
• At least one additional device class is specified in the storage field.

Devices not supported by LVM Storage

When adding device paths to the LVMCluster custom resource (CR), ensure devices are supported by LVM Storage. LVM Storage excludes unsupported devices to avoid complexity in managing logical volumes.

If you do not specify any device path in the deviceSelector field, LVM Storage adds only the unused devices that it supports.

Note

To get information about the devices, run the following command:

$ lsblk --paths --json -o \
NAME,ROTA,TYPE,SIZE,MODEL,VENDOR,RO,STATE,KNAME,SERIAL,PARTLABEL,FSTYPE

LVM Storage does not support the following devices:

Read-only devices

Devices with the ro parameter set to true.

Suspended devices

Devices with the state parameter set to suspended.

ROM devices

Devices with the type parameter set to rom.

LVM partition devices

Devices with the type parameter set to lvm.

Devices with invalid partition labels

Devices with the partlabel parameter set to bios, boot, or reserved.

Devices with an invalid filesystem

Devices with the fstype parameter set to any value other than null or LVM2_member.

Warning

LVM Storage supports devices with fstype parameter set to LVM2_member only if the devices do not contain children devices.

Devices that are part of another volume group

To get the information about the volume groups of the device, run the following command:

$ pvs <device-name>

Where <device-name> is the device name.

Devices with bind mounts

To get the mount points of a device, run the following command:

$ cat /proc/1/mountinfo | grep <device-name>

Where <device-name> is the device name.

Devices that contain children devices

:::note

: It is recommended to wipe the device before using it in LVM Storage to prevent unexpected behavior.

:::

Ways to create an LVMCluster custom resource

You can create an LVMCluster custom resource (CR) to configure LVM Storage deployment and provision storage for your workloads by using the OpenShift CLI (oc), OpenShift Container Platform web console, or Red Hat Advanced Cluster Management (RHACM).

You must install LVM Storage by using RHACM if you want to create an LVMCluster CR by using RHACM.

Warning

You must create the LVMCluster CR in the same namespace where you installed the LVM Storage Operator, which is openshift-storage by default.

After creating the LVMCluster CR, LVM Storage creates the following system-managed CRs:

• A storageClass and volumeSnapshotClass for each device class.

  Note

  LVM Storage configures the name of the storage class and volume snapshot class in the format lvms-<device_class_name>, where, <device_class_name> is the value of the deviceClasses.name field in the LVMCluster CR. For example, if the deviceClasses.name field is set to vg1, the name of the storage class and volume snapshot class is lvms-vg1.

• LVMVolumeGroup: This CR is a specific type of persistent volume (PV) that is backed by an LVM volume group. It tracks the individual volume groups across multiple nodes.

• LVMVolumeGroupNodeStatus: This CR tracks the status of the volume groups on a node.

Reusing a volume group from the previous LVM Storage installation

You can reuse an existing volume group (VG) from a previous LVM Storage installation to preserve your existing storage configuration and avoid recreating VGs when reinstalling or upgrading LVM Storage.

You can only reuse a VG, but not the logical volume associated with the VG.

Warning

You can perform this procedure only while creating an LVMCluster custom resource (CR).

Prerequisites

• The VG that you want to reuse must not be corrupted.
• The VG that you want to reuse must have the lvms tag. For more information on adding tags to LVM objects, see "Grouping LVM objects with tags".

Procedure

1. Open the LVMCluster CR YAML file.

2. Configure the LVMCluster CR parameters as described in the following example:

   Example LVMCluster CR YAML file

   apiVersion: lvm.topolvm.io/v1alpha1
   kind: LVMCluster
   metadata:
     name: my-lvmcluster
   spec:
   # ...
     storage:
       deviceClasses:
       - name: vg1
         fstype: ext4
         default: true
         deviceSelector:
   # ...
           forceWipeDevicesAndDestroyAllData: false
         thinPoolConfig:
   # ...
         nodeSelector:
   # ...
   

   • spec.storage.deviceClasses.name: Specifies the name of a VG from the previous LVM Storage installation.
   • spec.storage.deviceClasses.fstype: Set this field to ext4 or xfs. By default, this field is set to xfs.
   • spec.storage.deviceClasses.name.deviceSelector: You can add new devices to the VG that you want to reuse by specifying the new device paths in the deviceSelector field. If you do not want to add new devices to the VG, ensure that the deviceSelector configuration in the current LVM Storage installation is same as that of the previous LVM Storage installation.
   • spec...forceWipeDevicesAndDestroyAllData: If this field is set to true, LVM Storage wipes all the data on the devices that are added to the VG.
   • spec....thinPoolConfig: To retain the thinPoolConfig configuration of the VG that you want to reuse, ensure that the thinPoolConfig configuration in the current LVM Storage installation is same as that of the previous LVM Storage installation. Otherwise, you can configure the thinPoolConfig field as required.
   • spec...nodeSelector: Configure the requirements to choose the nodes on which you want to create the LVM volume group. If this field is empty, all nodes without no-schedule taints are considered.

3. Save the LVMCluster CR YAML file.

Verification

To view the devices that are part a volume group, run the following command:

$ pvs -S vgname=<vg_name>

Replace <vg_name> with the name of the volume group.

Additional resources

• Grouping LVM objects with tags

Creating an LVMCluster CR by using the CLI

You can create an LVMCluster custom resource (CR) on a worker node by using the OpenShift CLI (oc) to configure storage deployment and provision local storage for your workloads.

Warning

You can only create a single instance of the LVMCluster custom resource (CR) on an OpenShift Container Platform cluster.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to OpenShift Container Platform as a user with cluster-admin privileges.
• You have installed LVM Storage.
• You have installed a worker node in the cluster.
• You read "About the LVMCluster custom resource".

Procedure

1. Create an LVMCluster custom resource (CR) YAML file:

   Example LVMCluster CR YAML file

   apiVersion: lvm.topolvm.io/v1alpha1
   kind: LVMCluster
   metadata:
     name: my-lvmcluster
     namespace: openshift-lvm-storage
   spec:
   # ...
     storage:
       deviceClasses:
   # ...
         nodeSelector:
   # ...
         deviceSelector: 
   # ...
         thinPoolConfig:
   # ...
   

   • spec.storage.deviceClasses: Specifies the configuration to assign the local storage devices to the LVM volume groups.
   • spec...nodeSelector: Specifies the configuration to choose the nodes on which you want to create the LVM volume group. If this field is empty, all nodes without no-schedule taints are considered.
   • spec...deviceSelector: Specifies the configuration to specify the paths to the devices that you want to add to the LVM volume group, and force wipe the devices that are added to the LVM volume group.
   • spec...thinPoolConfig: Specifies the configuration to create a thin pool in the LVM volume group. If you exclude this field, logical volumes are thick provisioned.

2. Create the LVMCluster CR by running the following command:

   $ oc create -f <file_name>
   

   Example output

   lvmcluster/lvmcluster created
   

Verification

1. Check that the LVMCluster CR is in the Ready state by running the following command:

   $ oc get lvmclusters.lvm.topolvm.io -o jsonpath='{.items[*].status}' -n <namespace>
   

   Example output

   {"deviceClassStatuses":
   [ 
     {
       "name": "vg1", 
       "nodeStatus": [ 
           {
               "devices": [ 
                   "/dev/nvme0n1",
                   "/dev/nvme1n1",
                   "/dev/nvme2n1"
               ],
               "node": "kube-node", 
               "status": "Ready"
           }
       ]
     }
   ]
   "state":"Ready"}
   

   • deviceClassStatuses: Specifies the status of the device class.

   • nodeStatus: Specifies the status of the LVM volume group on each node.

   • devices: Specifies the list of devices used to create the LVM volume group.

   • node: Specifies the node on which the device class is created.

   • status: Specifies the status of the LVM volume group on the node.

   • state: Specifies the status of the LVMCluster CR.

     Note

     If the LVMCluster CR is in the Failed state, you can view the reason for failure in the status field. + Example of status field with the reason for failure:

     status:
       deviceClassStatuses:
         - name: vg1
           nodeStatus:
             - node: my-node-1.example.com 
               reason: no available devices found for volume group
               status: Failed
       state: Failed
     

2. To view the storage classes created by LVM Storage for each device class, run the following command:

   $ oc get storageclass
   

   Example output

   NAME          PROVISIONER          RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
   lvms-vg1      topolvm.io           Delete          WaitForFirstConsumer   true                   31m
   

3. To view the volume snapshot classes created by LVM Storage for each device class, run the following command:

   $ oc get volumesnapshotclass
   

   Example output

   NAME          DRIVER               DELETIONPOLICY   AGE
   lvms-vg1      topolvm.io           Delete           24h
   

Additional resources

• About the LVMCluster custom resource

Creating an LVMCluster CR by using the web console

You can create an LVMCluster custom resource (CR) on a worker node by using the OpenShift Container Platform web console to configure storage deployment and provision local storage for your workloads.

Warning

You can only create a single instance of the LVMCluster custom resource (CR) on an OpenShift Container Platform cluster.

Prerequisites

• You have access to the OpenShift Container Platform cluster with cluster-admin privileges.
• You have installed LVM Storage.
• You have installed a worker node in the cluster.
• You read the "About the LVMCluster custom resource" section.

Procedure

1. Log in to the OpenShift Container Platform web console.

2. Click Ecosystem → Installed Operators.

3. In the openshift-lvm-storage namespace, click LVM Storage.

4. Click Create LVMCluster and select either Form view or YAML view.

5. Configure the required LVMCluster CR parameters.

6. Click Create.

7. Optional: If you want to edit the LVMCLuster CR, perform the following actions:

   1. Click the LVMCluster tab.
   2. From the Actions menu, select Edit LVMCluster.
   3. Click YAML and edit the required LVMCLuster CR parameters.
   4. Click Save.

Verification

1. On the LVMCLuster page, check that the LVMCluster CR is in the Ready state.
2. Optional: To view the available storage classes created by LVM Storage for each device class, click Storage → StorageClasses.
3. Optional: To view the available volume snapshot classes created by LVM Storage for each device class, click Storage → VolumeSnapshotClasses.

Additional resources

• About the LVMCluster custom resource

Creating an LVMCluster CR by using RHACM

After installing Logical Volume Manager (LVM) Storage by using RHACM, create an LVMCluster custom resource (CR) to configure storage deployment, specify devices and volume groups, and provision storage for your workloads.

Prerequisites

• You have installed LVM Storage by using RHACM.
• You have access to the RHACM cluster using an account with cluster-admin permissions.
• You read the "About the LVMCluster custom resource" section.

Procedure

1. Log in to the RHACM CLI using your OpenShift Container Platform credentials.

2. Create a ConfigurationPolicy CR YAML file with the configuration to create an LVMCluster CR:

   Example ConfigurationPolicy CR YAML file to create an LVMCluster CR

   apiVersion: policy.open-cluster-management.io/v1
   kind: ConfigurationPolicy
   metadata:
     name: lvms
     namespace: openshift-lvm-storage
   spec:
     object-templates:
     - complianceType: musthave
       objectDefinition:
         apiVersion: lvm.topolvm.io/v1alpha1
         kind: LVMCluster
         metadata:
           name: my-lvmcluster
           namespace: openshift-lvm-storage
         spec:
           storage:
             deviceClasses:
   # ...
               deviceSelector:
   # ...
               thinPoolConfig:
   # ...
               nodeSelector:
   # ...
     remediationAction: enforce
     severity: low
   

   • spec.object-templates.objectDefinition.spec.storage.deviceClasses: Specifies the configuration to assign the local storage devices to the LVM volume groups.
   • spec...deviceSelector: Contains the configuration to specify the paths to the devices that you want to add to the LVM volume group, and force wipe the devices that are added to the LVM volume group.
   • spec...thinPoolConfig: Contains the configuration to create a thin pool in the LVM volume group. If you exclude this field, logical volumes are thick provisioned.
   • spec...nodeSelector: Contains the configuration to choose the nodes on which you want to create the LVM volume groups. If this field is empty, then all nodes without no-schedule taints are considered.

3. Create the ConfigurationPolicy CR by running the following command:

   $ oc create -f <file_name> -n <cluster_namespace>
   

   <cluster_namespace> is the namespace of the OpenShift Container Platform cluster on which LVM Storage is installed.

Additional resources

• About the LVMCluster custom resource

Ways to delete an LVMCluster custom resource

Delete an LVMCluster custom resource (CR) when decommissioning LVM Storage or reconfiguring storage by using the OpenShift CLI (oc), OpenShift Container Platform web console, or Red Hat Advanced Cluster Management (RHACM).

You must have installed LVM Storage by using RHACM to delete an LVMCluster CR by using RHACM.

After deleting the LVMCluster CR, LVM Storage deletes the following CRs:

• storageClass
• volumeSnapshotClass
• LVMVolumeGroup
• LVMVolumeGroupNodeStatus

Deleting an LVMCluster CR by using the CLI

You can delete an LVMCluster custom resource (CR) when decommissioning LVM Storage or reconfiguring storage by using the OpenShift CLI (oc).

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You have deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Delete the LVMCluster CR by running the following command:

   $ oc delete lvmcluster <lvm_cluster_name> -n <namespace>
   

Verification

• To verify that the LVMCluster CR has been deleted, run the following command:

  $ oc get lvmcluster -n <namespace>
  

  Example output

  No resources found in openshift-lvm-storage namespace.
  

Deleting an LVMCluster CR by using the web console

You can delete an LVMCluster custom resource (CR) when decommissioning LVM Storage or reconfiguring storage by using the OpenShift Container Platform web console.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You have deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.

Procedure

1. Log in to the OpenShift Container Platform web console.
2. Click Ecosystem → Installed Operators to view all the installed Operators.
3. Click LVM Storage in the openshift-lvm-storage namespace.
4. Click the LVMCluster tab.
5. From the Actions, select Delete LVMCluster.
6. Click Delete.

Verification

• On the LVMCLuster page, check that the LVMCluster CR has been deleted.

Deleting an LVMCluster CR by using RHACM

You can delete an LVMCluster custom resource (CR) when decommissioning LVM Storage or reconfiguring storage by using Red Hat Advanced Cluster Management (RHACM).

You can only delete an LVMCluster CR by using RHACM If you installed LVM Storage by using Red Hat Advanced Cluster Management (RHACM).

Prerequisites

• You have access to the RHACM cluster as a user with cluster-admin permissions.
• You have deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.

Procedure

1. Log in to the RHACM CLI using your OpenShift Container Platform credentials.

2. Delete the ConfigurationPolicy CR YAML file that was created for the LVMCluster CR:

   $ oc delete -f <file_name> -n <cluster_namespace>
   

   <cluster_namespace> is the namespace of the OpenShift Container Platform cluster on which LVM Storage is installed.

3. Create a Policy CR YAML file to delete the LVMCluster CR:

   Example Policy CR to delete the LVMCluster CR

   apiVersion: policy.open-cluster-management.io/v1
   kind: Policy
   metadata:
     name: policy-lvmcluster-delete
     annotations:
       policy.open-cluster-management.io/standards: NIST SP 800-53
       policy.open-cluster-management.io/categories: CM Configuration Management
       policy.open-cluster-management.io/controls: CM-2 Baseline Configuration
   spec:
     remediationAction: enforce
     disabled: false
     policy-templates:
       - objectDefinition:
           apiVersion: policy.open-cluster-management.io/v1
           kind: ConfigurationPolicy
           metadata:
             name: policy-lvmcluster-removal
           spec:
             remediationAction: enforce
             severity: low
             object-templates:
               - complianceType: mustnothave
                 objectDefinition:
                   kind: LVMCluster
                   apiVersion: lvm.topolvm.io/v1alpha1
                   metadata:
                     name: my-lvmcluster
                     namespace: openshift-lvm-storage
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: PlacementBinding
   metadata:
     name: binding-policy-lvmcluster-delete
   placementRef:
     apiGroup: apps.open-cluster-management.io
     kind: PlacementRule
     name: placement-policy-lvmcluster-delete
   subjects:
     - apiGroup: policy.open-cluster-management.io
       kind: Policy
       name: policy-lvmcluster-delete
   ---
   apiVersion: apps.open-cluster-management.io/v1
   kind: PlacementRule
   metadata:
     name: placement-policy-lvmcluster-delete
   spec:
     clusterConditions:
       - status: "True"
         type: ManagedClusterConditionAvailable
     clusterSelector:
       matchExpressions:
         - key: mykey
           operator: In
           values:
             - myvalue
   

   • spec.policy-templates.spec.remediationAction: This field is overridden by the preceding parameter value for spec.remediationAction.
   • spec.policy-templates.objectDefinition.spec.objectDefinition.metadata.namespace: This namespace field must have the openshift-lvm-storage value.
   • spec.clusterSelector: Configures the requirements to select the clusters. LVM Storage is uninstalled on the clusters that match the selection criteria.

4. Create the Policy CR by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

5. Create a Policy CR YAML file to check if the LVMCluster CR has been deleted:

   Example Policy CR to check if the LVMCluster CR has been deleted

   apiVersion: policy.open-cluster-management.io/v1
   kind: Policy
   metadata:
     name: policy-lvmcluster-inform
     annotations:
       policy.open-cluster-management.io/standards: NIST SP 800-53
       policy.open-cluster-management.io/categories: CM Configuration Management
       policy.open-cluster-management.io/controls: CM-2 Baseline Configuration
   spec:
     remediationAction: inform
     disabled: false
     policy-templates:
       - objectDefinition:
           apiVersion: policy.open-cluster-management.io/v1
           kind: ConfigurationPolicy
           metadata:
             name: policy-lvmcluster-removal-inform
           spec:
             remediationAction: inform
             severity: low
             object-templates:
               - complianceType: mustnothave
                 objectDefinition:
                   kind: LVMCluster
                   apiVersion: lvm.topolvm.io/v1alpha1
                   metadata:
                     name: my-lvmcluster
                     namespace: openshift-lvm-storage
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: PlacementBinding
   metadata:
     name: binding-policy-lvmcluster-check
   placementRef:
     apiGroup: apps.open-cluster-management.io
     kind: PlacementRule
     name: placement-policy-lvmcluster-check
   subjects:
     - apiGroup: policy.open-cluster-management.io
       kind: Policy
       name: policy-lvmcluster-inform
   ---
   apiVersion: apps.open-cluster-management.io/v1
   kind: PlacementRule
   metadata:
     name: placement-policy-lvmcluster-check
   spec:
     clusterConditions:
       - status: "True"
         type: ManagedClusterConditionAvailable
     clusterSelector:
       matchExpressions:
         - key: mykey
           operator: In
           values:
             - myvalue
   

   • spec.policy-templates.objectDefinition.spec.remediationAction: This field is overridden by the preceding parameter value for spec.remediationAction.
   • spec.policy-templates.objectDefinition.spec.object-templates.objectDefinition.metadata.namespace: This namespace field must have the openshift-lvm-storage value.

6. Create the Policy CR by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

Verification

• Check the status of the Policy CRs by running the following command:

  $ oc get policy -n <namespace>
  

  Example output

  NAME                       REMEDIATION ACTION   COMPLIANCE STATE   AGE
  policy-lvmcluster-delete   enforce              Compliant          15m
  policy-lvmcluster-inform   inform               Compliant          15m
  

  Warning

  The Policy CRs must be in Compliant state.

Deleting an LVMCluster

When you delete an LVMCluster custom resource (CR), the Operator enforces deletion gates to prevent data loss. The gates that apply depend on the reclaim policy that is configured for the storage class.

Prerequisites

• You have administrative access to the cluster.
• You have identified the reclaim policy in use: Delete or Retain.

Procedure

1. Delete all Persistent Volume Claims (PVCs) that reference LVM StorageClass resources.

   If PVCs that reference LVM StorageClasses still exist, the Operator blocks LVMCluster deletion and generates a DeletionPending event:

   found PVCs provisioned by LVMS, waiting 10s for their deletion
   

2. Back up any data before deleting PVCs.

   1. List the PVCs that use the LVM StorageClass by running the following command:

      $ oc get pvc -A -o custom-columns='NAMESPACE:.metadata.namespace,NAME:.metadata.name,SC:.spec.storageClassName' | grep lvms-vg1
      

   2. Delete the PVCs by running the following command:

      $ oc delete pvc <pvc_name> -n <namespace>
      

      With the Delete reclaim policy, deleting the PVCs automatically removes the persistent volumes (PVs) and on-disk logical volumes. After all PVCs are removed, LVMCluster deletion completes automatically. No further action is required.

3. If you use the Retain reclaim policy, delete the retained PVs.

   After you delete PVCs, if the reclaim policy is Retain, the Operator blocks LVMCluster deletion and generates a DeletionPending event:

   found PVs with Retain policy from LVMS, waiting 10s for manual cleanup
   

   1. List the retained PVs by running the following command:

      $ oc get pv -o custom-columns='NAME:.metadata.name,SC:.spec.storageClassName' | grep lvms-vg1
      

   2. Delete the PVs by running the following command:

      $ oc delete pv <pv_name>
      

4. If you are using the Retain reclaim policy, delete the TopoLVM LogicalVolume custom resources.

   After you delete PV objects from Kubernetes, the underlying logical volumes remain on disk because the Retain policy preserved them. The VG Manager detects this and generates a ManualCleanupRequired event:

   Warning  ManualCleanupRequired  volume group vg1 has retained logical volumes [pvc-abc123]; manual cleanup required before deletion can proceed
   

5. Deleting the LogicalVolume custom resources triggers on-disk logical volume cleanup.

   1. List the LogicalVolume custom resources by running the following command:

      $ oc get logicalvolumes
      

   2. Delete the LogicalVolume custom resources for your device class by running the following command:

      $ oc delete logicalvolume <lv_name>
      

Verification

• Verify that the LVMCluster deletion completed by confirming the resource no longer exists by running the following command:

  $ oc get lvmcluster -A
  

Provisioning storage by using LVM Storage

After you have created the LVM volume groups by using the LVMCluster custom resource (CR), you can provision storage for your workloads by creating persistent volume claims (PVCs) that dynamically allocate local storage from the volume groups.

The following are the minimum storage sizes that you can request for each file system type:

• block: 8 MiB
• xfs: 300 MiB
• ext4: 32 MiB

To create a PVC, you must create a PersistentVolumeClaim object.

Prerequisites

• You have created an LVMCluster CR.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Create a PersistentVolumeClaim object:

   Example PersistentVolumeClaim object

   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: lvm-block-1
     namespace: default
   spec:
     accessModes:
       - ReadWriteOnce
     volumeMode: Filesystem
     resources:
       requests:
         storage: 10Gi
       limits:
         storage: 20Gi
     storageClassName: lvms-vg1
   

   • metadata.name: Specifies a name for the PVC.

   • spec.volumeMode: To create a file PVC, set this field to Filesystem. To create a block PVC, set this field to Block.

   • spec.resources.requests.storage: Specifies the storage size. If the value is less than the minimum storage size, the requested storage size is rounded to the minimum storage size. The total storage size you can provision is limited by the size of the Logical Volume Manager (LVM) thin pool and the over-provisioning factor.

   • spec.resources.limits.storage: (optional) Specifies the storage limit. Set this field to a value that is greater than or equal to the minimum storage size. Otherwise, PVC creation fails with an error.

   • spec.storageClassName: The value of the storageClassName field must be in the format lvms-<device_class_name> where <device_class_name> is the value of the deviceClasses.name field in the LVMCluster CR.

     For example, if the deviceClasses.name field is set to vg1, you must set the storageClassName field to lvms-vg1.

     Note

     The volumeBindingMode field of the storage class is set to WaitForFirstConsumer.

3. Create the PVC by running the following command:

   # oc create -f <file_name> -n <application_namespace>
   

   Note

   The created PVCs remain in Pending state until you deploy the pods that use them.

Verification

• To verify that the PVC is created, run the following command:

  $ oc get pvc -n <namespace>
  

  Example output

  NAME          STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  lvm-block-1   Bound    pvc-e90169a8-fd71-4eea-93b8-817155f60e47   1Gi        RWO            lvms-vg1       5s
  

StorageClass customization for LVMS device classes

You can customize the StorageClass for each device class by specifying reclaim policy, volume binding mode, parameters, and labels in the LVMCluster custom resource (CR).

Before, Logical Volume Manager Storage (LVMS) automatically created a StorageClass for each device class without allowing modification. If you attempted to manually edit a generated StorageClass, the Operator overwrote your changes during the next reconciliation loop.

The storageClassOptions field lets you control four properties of the generated StorageClass:

• reclaimPolicy
• volumeBindingMode
• additionalParameters
• additionalLabels

If you omit storageClassOptions, LVMS creates the StorageClass with the same defaults as in previous versions. Existing LVMCluster configurations are fully compatible with earlier versions.

Note

No user action is required after upgrading. The storageClassOptions field is optional, and default values match the behavior before this feature was introduced.

StorageClass options for LVMS device classes

You can configure custom StorageClass behaviors for each device class, including reclaim policy, volume binding mode, and custom parameters and labels, by defining the storageClassOptions field in the LVMCluster custom resource.

If you set an empty configuration (storageClassOptions: {}) or omit the field entirely, the Operator uses the following default settings:

StorageClass Options Reference

Field	Type	Immutable	Description	Example
reclaimPolicy	string	Yes	Controls what happens to the PersistentVolume (PV) and its underlying logical volume when the PersistentVolumeClaim (PVC) is deleted. Allowed values: Delete (default), Retain When set to Retain, deleting a PVC does not delete the PV or the underlying logical volume on disk. Data is preserved, useful for data protection scenarios where accidental PVC deletion must not cause data loss. Manual cleanup is required before you can delete the LVMCluster. When set to Delete, both the PV and the on-disk logical volume are removed when the PVC is deleted.	storageClassOptions: reclaimPolicy: Retain
volumeBindingMode	string	Yes	Controls when volume binding and dynamic provisioning occur. Allowed values: WaitForFirstConsumer (default), Immediate WaitForFirstConsumer delays PV provisioning until a pod that uses the PVC is scheduled, enabling topology-aware scheduling where LVMS creates the PV on the node where the pod will run. Immediate provisions and binds the PV as soon as the PVC is created, without waiting for a consumer pod. On multi-node clusters, PVs might be provisioned on nodes where the consuming pod cannot run. Use Immediate only on single-node clusters or when node affinity is managed externally.	storageClassOptions: volumeBindingMode: Immediate
additionalParameters	map[string]string	Yes	Adds custom key-value pairs to the StorageClass .parameters map. Default: {} (empty). Maximum entries: 16. StorageClass parameters are passed to the CSI driver (TopoLVM) during volume provisioning. TopoLVM recognizes only topolvm.io/device-class and csi.storage.k8s.io/fstype. Use additionalParameters for forward-compatibility or for parameters consumed by other Kubernetes components. The following keys are managed by LVMS and are rejected at admission: topolvm.io/device-class — automatically set to the device class name csi.storage.k8s.io/fstype — automatically set from the fstype field on the device class Important To change the filesystem type, use the fstype field on the device class directly. Do not use additionalParameters.	storageClassOptions: additionalParameters: custom-param-key: custom-param-value
additionalLabels	map[string]string	No	Adds custom labels to the StorageClass metadata. Default: none. Maximum entries: 16. Use for organizational tagging, cluster policy integration, or monitoring. When you remove a label from additionalLabels, the operator removes it from the StorageClass during the next reconciliation. Labels added directly by other tools are not affected. The following label keys are reserved and cannot be set through additionalLabels: app.kubernetes.io/managed-by app.kubernetes.io/part-of app.kubernetes.io/name app.kubernetes.io/component Any key with the prefix owned-by.topolvm.io/	storageClassOptions: additionalLabels: environment: production team: storage

Updating LVM cluster labels

To organize and categorize your storage resources, you can update, remove, or clear custom StorageClass labels by patching the additionalLabels field in the LVMCluster custom resource.

Procedure

1. Patch the LVMCluster resource to update additionalLabels by running the following command:

   $ oc -n openshift-lvm-storage patch lvmcluster <name> --type=json \
     -p '[{"op":"replace","path":"/spec/storage/deviceClasses/0/storageClassOptions/additionalLabels","value":{"environment":"staging"}}]'
   

2. To remove a specific label, update additionalLabels without the label you want to remove. The Operator removes the label from the StorageClass during the next reconciliation.

3. To remove all custom labels, set additionalLabels to an empty map {}.

   Note

   The Operator preserves labels that you add directly to the StorageClass, for example with oc label storageclass lvms-vg1 my-label=value. The Operator prunes only the labels that you manage through the additionalLabels field in the LVMCluster custom resource (CR) when you remove them from the CR.

Sample LVM cluster configuration with storage class option

Use these examples to configure storageClassOptions in your LVMCluster custom resource (CR) to meet your specific storage requirements.

Default StorageClass behavior (no options)

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
  namespace: openshift-lvm-storage
spec:
  storage:
    deviceClasses:
    - name: vg1
      default: true
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10

This produces a StorageClass with reclaimPolicy: Delete and volumeBindingMode: WaitForFirstConsumer, which is the same as the behavior before this feature.

Retain policy for data protection

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
  namespace: openshift-lvm-storage
spec:
  storage:
    deviceClasses:
    - name: vg1
      default: true
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10
      storageClassOptions:
        reclaimPolicy: Retain

Immediate binding for pre-provisioning

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
  namespace: openshift-lvm-storage
spec:
  storage:
    deviceClasses:
    - name: vg1
      default: true
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10
      storageClassOptions:
        volumeBindingMode: Immediate

All options configured together

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
  namespace: openshift-lvm-storage
spec:
  storage:
    deviceClasses:
    - name: vg1
      default: true
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10
      storageClassOptions:
        reclaimPolicy: Retain
        volumeBindingMode: WaitForFirstConsumer
        additionalParameters:
          custom-key: custom-value
        additionalLabels:
          environment: production
          team: storage

Multiple device classes with different options

apiVersion: lvm.topolvm.io/v1alpha1
kind: LVMCluster
metadata:
  name: my-lvmcluster
  namespace: openshift-lvm-storage
spec:
  storage:
    deviceClasses:
    - name: vg-fast
      default: true
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10
      deviceSelector:
        paths:
        - /dev/nvme0n1
      storageClassOptions:
        reclaimPolicy: Delete
        volumeBindingMode: WaitForFirstConsumer
        additionalLabels:
          tier: fast
    - name: vg-archive
      thinPoolConfig:
        name: thin-pool-1
        sizePercent: 90
        overprovisionRatio: 10
      deviceSelector:
        paths:
        - /dev/sda
      storageClassOptions:
        reclaimPolicy: Retain
        volumeBindingMode: WaitForFirstConsumer
        additionalLabels:
          tier: archive

For a device class named vg1 with the full configuration, LVMS generates a StorageClass named lvms-vg1 with the following structure:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: lvms-vg1
  annotations:
    description: "Provides RWO and RWOP Filesystem & Block volumes"
    storageclass.kubernetes.io/is-default-class: "true"
  labels:
    environment: production
    team: storage
provisioner: topolvm.io
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
parameters:
  custom-key: custom-value
  topolvm.io/device-class: vg1
  csi.storage.k8s.io/fstype: xfs

The StorageClass name always follows the convention lvms-<device_class_name>.

Immutable fields of the storage class options

After you create the LVMCluster custom resource, you cannot change certain storageClassOptions fields, such as reclaimPolicy, volumeBindingMode, and additionalParameters. To change an immutable field, you must delete and recreate the LVMCluster with the new values.

This mirrors the behavior of Kubernetes StorageClasses, which do not allow changes to these fields after creation.

If you attempt to modify an immutable field, the API server rejects the request:

Invalid value: "object": reclaimPolicy is immutable once set

There is no way to patch or update immutable fields in place. To change an immutable field, you must delete the LVMCluster and recreate it with the new values.

For example, you cannot change the filesystem type through additionalParameters. The csi.storage.k8s.io/fstype parameter is managed by LVMS and is rejected at admission if set through additionalParameters. To use ext4 instead of the default xfs, use the fstype field on the device class:

deviceClasses:
- name: vg1
  fstype: ext4

However, the fstype field is also immutable after creation.

Note

The deletion gates require all PVCs and, for the Retain policy, all PVs to be removed before the LVMCluster can be deleted. After you recreate the LVMCluster with the new values, new PVCs use the updated StorageClass configuration.

Behaviors not controlled by StorageClass options

Review these behaviors before you delete an LVMCluster. Although these behaviors relate to storageClassOptions, the storageClassOptions field does not control them.

Volume expansion behavior

Logical Volume Manager Storage (LVMS) always enables volume expansion by setting allowVolumeExpansion: true on generated StorageClasses. You cannot control this setting by using the storageClassOptions field. All LVMS volumes support online expansion.

VolumeSnapshotClass management

The storageClassOptions field only affects StorageClasses. When you configure thin provisioning, LVMS generates a VolumeSnapshotClass for each device class. This generated class always uses a fixed value deletionPolicy: Delete, regardless of the reclaimPolicy that you set in storageClassOptions.

Additionally, LVMS does not apply the additionalParameters and additionalLabels fields to VolumeSnapshotClasses. If you need to retain snapshot data, you must manage it separately from the StorageClass reclaim policy.

Default StorageClass annotation behavior

The default field on a device class controls the storageclass.kubernetes.io/is-default-class annotation on the generated StorageClass.

Setting default: true does not guarantee that the LVMS StorageClass becomes the cluster default. If another default StorageClass already exists on the cluster, for example, gp3-csi on AWS-based OpenShift Container Platform clusters, LVMS sets the annotation to false to prevent many cluster-wide defaults. Because the Operator actively manages this annotation, it reverts any manual, out-of-band changes during the next reconciliation loop.

Ways to scale up the storage of clusters

Scale up worker node storage capacity when running out of space, adding new applications, or expanding cluster capacity by using the OpenShift CLI (oc) to add new devices or worker nodes.

OpenShift Container Platform supports additional worker nodes for clusters on bare metal user-provisioned infrastructure.

Logical Volume Manager (LVM) Storage detects and uses additional worker nodes when the nodes become active.

To add a new device to the existing worker nodes on a cluster, you must add the path to the new device in the deviceSelector field of the LVMCluster custom resource (CR).

Warning

You can add the deviceSelector field in the LVMCluster CR only while creating the LVMCluster CR. If you have not added the deviceSelector field while creating the LVMCluster CR, you must delete the LVMCluster CR and create a new LVMCluster CR containing the deviceSelector field.

If you do not add the deviceSelector field in the LVMCluster CR, LVM Storage automatically adds the new devices when the devices are available.

Note

LVM Storage adds only the supported devices. For information about unsupported devices, see "Devices not supported by LVM Storage".

Additional resources

• Adding worker nodes to single-node OpenShift clusters
• Devices not supported by LVM Storage

Scaling up the storage of clusters by using the CLI

Scale up worker node storage capacity when running out of space, adding new applications, or expanding cluster capacity by using the OpenShift CLI (oc) to add new devices or worker nodes.

Prerequisites

• You have additional unused devices on each cluster to be used by Logical Volume Manager (LVM) Storage.
• You have installed the OpenShift CLI (oc).
• You have created an LVMCluster custom resource (CR).

Procedure

1. Edit the LVMCluster CR by running the following command:

   $ oc edit <lvmcluster_file_name> -n <namespace>
   

2. Add the path to the new device in the deviceSelector field.

   Example LVMCluster CR

   apiVersion: lvm.topolvm.io/v1alpha1
   kind: LVMCluster
   metadata:
     name: my-lvmcluster
   spec:
     storage:
       deviceClasses:
   # ...
         deviceSelector:
           paths:
           - /dev/disk/by-path/pci-0000:87:00.0-nvme-1
           - /dev/disk/by-path/pci-0000:88:00.0-nvme-1
           optionalPaths:
           - /dev/disk/by-path/pci-0000:89:00.0-nvme-1
           - /dev/disk/by-path/pci-0000:90:00.0-nvme-1
   # ...
   

   • spec...deviceSelector: Contains the configuration to specify the paths to the devices that you want to add to the LVM volume group. You can specify the device paths in the paths field, the optionalPaths field, or both. If you do not specify the device paths in both paths and optionalPaths, Logical Volume Manager (LVM) Storage adds the supported unused devices to the LVM volume group. LVM Storage adds the devices to the LVM volume group only if the following conditions are met:

     • The device path exists.
     • The device is supported by LVM Storage. For information about unsupported devices, see "Devices not supported by LVM Storage".

   • spec...deviceSelector.paths: Specifies the device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, the LVMCluster CR moves to the Failed state.

   • spec...deviceSelector.optionalPaths: Specifies the optional device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, LVM Storage ignores the device without causing an error.

     Warning

     After a device is added to the LVM volume group, it cannot be removed.

3. Save the LVMCluster CR.

Additional resources

• About the LVMCluster custom resource
• Devices not supported by LVM Storage
• About adding devices to a volume group

Scaling up the storage of clusters by using the web console

Scale up worker node storage capacity when running out of space, adding new applications, or expanding cluster capacity by using the OpenShift Container Platform web console to add new devices or worker nodes.

Prerequisites

• You have additional unused devices on each cluster to be used by Logical Volume Manager (LVM) Storage.
• You have created an LVMCluster custom resource (CR).

Procedure

1. Log in to the OpenShift Container Platform web console.

2. Click Ecosystem → Installed Operators.

3. Click LVM Storage in the openshift-lvm-storage namespace.

4. Click the LVMCluster tab to view the LVMCluster CR created on the cluster.

5. From the Actions menu, select Edit LVMCluster.

6. Click the YAML tab.

7. Edit the LVMCluster CR to add the new device path in the deviceSelector field:

   Example LVMCluster CR

   apiVersion: lvm.topolvm.io/v1alpha1
   kind: LVMCluster
   metadata:
     name: my-lvmcluster
   spec:
     storage:
       deviceClasses:
   # ...
         deviceSelector:
           paths:
           - /dev/disk/by-path/pci-0000:87:00.0-nvme-1
           - /dev/disk/by-path/pci-0000:88:00.0-nvme-1
           optionalPaths:
           - /dev/disk/by-path/pci-0000:89:00.0-nvme-1
           - /dev/disk/by-path/pci-0000:90:00.0-nvme-1
   # ...
   

   • spec...deviceSelector: Contains the configuration to specify the paths to the devices that you want to add to the LVM volume group. You can specify the device paths in the paths field, the optionalPaths field, or both. If you do not specify the device paths in both paths and optionalPaths, Logical Volume Manager (LVM) Storage adds the supported unused devices to the LVM volume group. LVM Storage adds the devices to the LVM volume group only if the following conditions are met:

     • The device path exists.
     • The device is supported by LVM Storage. For information about unsupported devices, see "Devices not supported by LVM Storage".

   • spec...deviceSelector.paths: Specifies the device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, the LVMCluster CR moves to the Failed state.

   • spec...deviceSelector.optionalPaths: Specifies the optional device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, LVM Storage ignores the device without causing an error.

     Warning

     After a device is added to the LVM volume group, it cannot be removed.

8. Click Save.

Additional resources

• About the LVMCluster custom resource
• Devices not supported by LVM Storage
• About adding devices to a volume group

Scaling up the storage of clusters by using RHACM

Scale up worker node storage capacity when running out of space, adding new applications, or expanding cluster capacity by using RHACM to add new devices or worker nodes.

Prerequisites

• You have access to the RHACM cluster using an account with cluster-admin privileges.
• You have created an LVMCluster custom resource (CR) by using RHACM.
• You have additional unused devices on each cluster to be used by Logical Volume Manager (LVM) Storage.

Procedure

1. Log in to the RHACM CLI using your OpenShift Container Platform credentials.

2. Edit the LVMCluster CR that you created using RHACM by running the following command:

   $ oc edit -f <file_name> -n <namespace>
   

   Replace <file_name> with the name of the LVMCluster CR.

3. In the LVMCluster CR, add the path to the new device in the deviceSelector field.

   Example LVMCluster CR

   apiVersion: policy.open-cluster-management.io/v1
   kind: ConfigurationPolicy
   metadata:
     name: lvms
   spec:
     object-templates:
        - complianceType: musthave
          objectDefinition:
            apiVersion: lvm.topolvm.io/v1alpha1
            kind: LVMCluster
            metadata:
              name: my-lvmcluster
              namespace: openshift-lvm-storage
            spec:
              storage:
                deviceClasses:
   # ...
                  deviceSelector:
                    paths:
                    - /dev/disk/by-path/pci-0000:87:00.0-nvme-1
                    optionalPaths:
                    - /dev/disk/by-path/pci-0000:89:00.0-nvme-1
   # ...
   

   • deviceSelector: Contains the configuration to specify the paths to the devices that you want to add to the LVM volume group. You can specify the device paths in the paths field, the optionalPaths field, or both. If you do not specify the device paths in both paths and optionalPaths, Logical Volume Manager (LVM) Storage adds the supported unused devices to the LVM volume group. LVM Storage adds the devices to the LVM volume group only if the following conditions are met:

     • The device path exists.
     • The device is supported by LVM Storage. For information about unsupported devices, see "Devices not supported by LVM Storage".

   • paths: Specifies the device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, the LVMCluster CR moves to the Failed state.

   • optionalPaths: Specifies the optional device paths. If the device path specified in this field does not exist, or the device is not supported by LVM Storage, LVM Storage ignores the device without causing an error.

     Warning

     After a device is added to the LVM volume group, it cannot be removed.

4. Save the LVMCluster CR.

Additional resources

• About the LVMCluster custom resource
• Devices not supported by LVM Storage
• About adding devices to a volume group

Expanding a persistent volume claim

After scaling up cluster storage, you can expand existing persistent volume claims (PVCs) to increase their storage capacity by updating the storage field in the PVC.

Prerequisites

• Dynamic provisioning is used.
• The StorageClass object associated with the PVC has the allowVolumeExpansion field set to true.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Update the value of the spec.resources.requests.storage field to a value that is greater than the current value by running the following command:

   $ oc patch pvc <pvc_name> -n <application_namespace> \
     --type=merge -p \ '{ "spec": { "resources": { "requests": { "storage": "<desired_size>" }}}}'
   

   • Replace <pvc_name> with the name of the PVC that you want to expand.
   • Replace <desired_size> with the new size to expand the PVC.

Verification

• To verify that resizing is completed, run the following command:

  $ oc get pvc <pvc_name> -n <application_namespace> -o=jsonpath={.status.capacity.storage}
  

  LVM Storage adds the Resizing condition to the PVC during expansion. It deletes the Resizing condition after the PVC expansion.

Additional resources

• Ways to scale up the storage of clusters
• Enabling volume expansion support

Deleting a persistent volume claim

You can delete a persistent volume claim (PVC) when it is no longer needed to free up storage resources or when decommissioning an application by using the OpenShift CLI (oc).

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Delete the PVC by running the following command:

   $ oc delete pvc <pvc_name> -n <namespace>
   

Verification

• To verify that the PVC is deleted, run the following command:

  $ oc get pvc -n <namespace>
  

  The deleted PVC must not be present in the output of this command.

About volume snapshots

You can create volume snapshots of persistent volume claims (PVCs) provisioned by LVM Storage to back up application data or revert to a previous state, providing data protection and recovery capabilities.

You can perform the following actions using the volume snapshots:

• Back up your application data.

  Warning

  Volume snapshots are located on the same devices as the original data. To use the volume snapshots as backups, you must move the snapshots to a secure location. You can use OpenShift API for Data Protection (OADP) backup and restore solutions. For information about OADP, see "OADP features".

• Revert to a state at which the volume snapshot was taken.

Note

You can also create volume snapshots of the volume clones.

Limitations for creating volume snapshots in multi-node topology

LVM Storage has the following limitations for creating volume snapshots in multi-node topology:

• Creating volume snapshots is based on the LVM thin pool capabilities.
• After creating a volume snapshot, the node must have additional storage space for further updating the original data source.
• You can create volume snapshots only on the node where you have deployed the original data source.
• Pods relying on the PVC that uses the snapshot data can be scheduled only on the node where you have deployed the original data source.

Additional resources

• OADP features

Creating volume snapshots

Create volume snapshots to capture point-in-time copies of persistent volume claims (PVCs) for data backup or recovery purposes by creating a VolumeSnapshot object, based on the available thin pool capacity and over-provisioning limits.

To create a volume snapshot, you must create a VolumeSnapshotClass object.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You ensured that the persistent volume claim (PVC) is in Bound state. This is required for a consistent snapshot.
• You stopped all the I/O to the PVC.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Create a VolumeSnapshot object:

   Example VolumeSnapshot object

   apiVersion: snapshot.storage.k8s.io/v1
   kind: VolumeSnapshot
   metadata:
     name: lvm-block-1-snap
   spec:
     source:
       persistentVolumeClaimName: lvm-block-1
     volumeSnapshotClassName: lvms-vg1
   

   • metadata.name: Specifies a name for the volume snapshot.

   • spec.source.persistentVolumeClaimName: Specifies the name of the source PVC. LVM Storage creates a snapshot of this PVC.

   • spec.volumeSnapshotClassName: Specifies the name of a volume snapshot class.

     Note

     To get the list of available volume snapshot classes, run the following command:

     $ oc get volumesnapshotclass
     

3. Create the volume snapshot in the namespace where you created the source PVC by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

   LVM Storage creates a read-only copy of the PVC as a volume snapshot.

Verification

• To verify that the volume snapshot is created, run the following command:

  $ oc get volumesnapshot -n <namespace>
  

  Example output

  NAME               READYTOUSE   SOURCEPVC     SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS   SNAPSHOTCONTENT                                    CREATIONTIME   AGE
  lvm-block-1-snap   true         lvms-test-1                           1Gi           lvms-vg1        snapcontent-af409f97-55fc-40cf-975f-71e44fa2ca91   19s            19s
  

  The value of the READYTOUSE field for the volume snapshot that you created must be true.

Restoring volume snapshots

Restore volume snapshots to recover data from a previous point in time by creating a persistent volume claim (PVC) that references the snapshot, producing an independent copy separate from the original snapshot and source PVC.

To restore a volume snapshot, you must create a persistent volume claim (PVC) with the dataSource.name field set to the name of the volume snapshot.

The restored PVC is independent of the volume snapshot and the source PVC.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You have created a volume snapshot.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Create a PersistentVolumeClaim object with the configuration to restore the volume snapshot:

   Example PersistentVolumeClaim object to restore a volume snapshot

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: lvm-block-1-restore
   spec:
     accessModes:
     - ReadWriteOnce
     volumeMode: Block
     Resources:
       Requests:
         storage: 2Gi
     storageClassName: lvms-vg1
     dataSource:
       name: lvm-block-1-snap
       kind: VolumeSnapshot
       apiGroup: snapshot.storage.k8s.io
   

   • spec.Resources.Requests.storage: Specifies the storage size of the restored PVC. The storage size of the requested PVC must be greater than or equal to the storage size of the volume snapshot that you want to restore. If a larger PVC is required, you can also resize the PVC after restoring the volume snapshot.
   • spec.storageClassName: Set this field to the value of the storageClassName field in the source PVC of the volume snapshot that you want to restore.
   • spec.dataSource.name: Set this field to the name of the volume snapshot that you want to restore.

3. Create the PVC in the namespace where you created the volume snapshot by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

Verification

• To verify that the volume snapshot is restored, run the following command:

  $ oc get pvc -n <namespace>
  

  Example output

  NAME                  STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  lvm-block-1-restore   Bound    pvc-e90169a8-fd71-4eea-93b8-817155f60e47   1Gi        RWO            lvms-vg1       5s
  

Deleting volume snapshots

Delete volume snapshots when they are no longer needed to free up storage resources and prevent orphaned snapshots, since LVM Storage does not automatically delete snapshots when you delete the source persistent volume claim (PVC).

Warning

When you delete a persistent volume claim (PVC), LVM Storage deletes only the PVC, but not the snapshots of the PVC.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You have ensured that the volume snapshot that you want to delete is not in use.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Delete the volume snapshot by running the following command:

   $ oc delete volumesnapshot <volume_snapshot_name> -n <namespace>
   

Verification

• To verify that the volume snapshot is deleted, run the following command:

  $ oc get volumesnapshot -n <namespace>
  

  The deleted volume snapshot must not be present in the output of this command.

About volume clones

A volume clone is a duplicate of an existing persistent volume claim (PVC) that creates a point-in-time copy of data more efficiently than snapshots, useful for testing, development, or creating independent copies of application data.

Limitations for creating volume clones in multi-node topology

LVM Storage has the following limitations for creating volume clones in multi-node topology:

• Creating volume clones is based on the LVM thin pool capabilities.
• The node must have additional storage after creating a volume clone for further updating the original data source.
• You can create volume clones only on the node where you have deployed the original data source.
• Pods relying on the PVC that uses the clone data can be scheduled only on the node where you have deployed the original data source.

Creating volume clones

Create volume clones to duplicate persistent volume claim (PVC) data for testing, development, or creating independent writable copies by creating a PersistentVolumeClaim object that references the source PVC.

You must create a PersistentVolumeClaim object in the namespace where you created the source PVC.

Warning

The cloned PVC has write access.

Prerequisites

• You ensured that the source PVC is in Bound state. This is required for a consistent clone.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Create a PersistentVolumeClaim object:

   Example PersistentVolumeClaim object to create a volume clone

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: lvm-pvc-clone
   spec:
     accessModes:
     - ReadWriteOnce
     storageClassName: lvms-vg1
     volumeMode: Filesystem
     dataSource:
       kind: PersistentVolumeClaim
       name: lvm-pvc
     resources:
       requests:
         storage: 1Gi
   

   • spec.storageClassName: Set this field to the value of the storageClassName field in the source PVC.
   • spec.volumeMode: Set this field to the volumeMode field in the source PVC.
   • spec.dataSource.name: Specifies the name of the source PVC.
   • spec.resources.requests.storage: Specifies the storage size for the cloned PVC. The storage size of the cloned PVC must be greater than or equal to the storage size of the source PVC.

3. Create the PVC in the namespace where you created the source PVC by running the following command:

   $ oc create -f <file_name> -n <namespace>
   

Verification

• To verify that the volume clone is created, run the following command:

  $ oc get pvc -n <namespace>
  

  Example output

  NAME                STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  lvm-block-1-clone   Bound    pvc-e90169a8-fd71-4eea-93b8-817155f60e47   1Gi        RWO            lvms-vg1       5s
  

Deleting volume clones

Delete volume clones when they are no longer needed to free up storage resources, since LVM Storage does not automatically delete clones when you delete the source persistent volume claim (PVC).

Warning

When you delete a persistent volume claim (PVC), LVM Storage deletes only the source persistent volume claim (PVC) but not the clones of the PVC.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Delete the cloned PVC by running the following command:

   $ oc delete pvc <clone_pvc_name> -n <namespace>
   

Verification

• To verify that the volume clone is deleted, run the following command:

  $ oc get pvc -n <namespace>
  

  The deleted volume clone must not be present in the output of this command.

Updating LVM Storage

You can update LVM Storage to ensure compatibility with the OpenShift Container Platform version after upgrading your cluster.

Note

The default namespace for the LVM Storage Operator is openshift-lvm-storage.

Prerequisites

• You have updated your OpenShift Container Platform cluster.
• You have installed a previous version of LVM Storage.
• You have installed the OpenShift CLI (oc).
• You have access to the cluster using an account with cluster-admin permissions.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Update the Subscription custom resource (CR) that you created while installing LVM Storage by running the following command:

   $ oc patch subscription lvms-operator -n openshift-lvm-storage --type merge --patch '{"spec":{"channel":"<update_channel>"}}'
   

   Replace <update_channel> with the version of LVM Storage that you want to install. For example, stable-4.22.

3. View the update events to check that the installation is complete by running the following command:

   $ oc get events -n openshift-lvm-storage
   

   Example output

   ...
   8m13s       Normal    RequirementsUnknown   clusterserviceversion/lvms-operator.v4.22   requirements not yet checked
   8m11s       Normal    RequirementsNotMet    clusterserviceversion/lvms-operator.v4.22   one or more requirements couldn't be found
   7m50s       Normal    AllRequirementsMet    clusterserviceversion/lvms-operator.v4.22   all requirements found, attempting install
   7m50s       Normal    InstallSucceeded      clusterserviceversion/lvms-operator.v4.22   waiting for install components to report healthy
   7m49s       Normal    InstallWaiting        clusterserviceversion/lvms-operator.v4.22   installing: waiting for deployment lvms-operator to become ready: deployment "lvms-operator" waiting for 1 outdated replica(s) to be terminated
   7m39s       Normal    InstallSucceeded      clusterserviceversion/lvms-operator.v4.22   install strategy completed with no errors
   ...
   

Verification

• Verify the LVM Storage version by running the following command:

  $ oc get subscription lvms-operator -n openshift-lvm-storage -o jsonpath='{.status.installedCSV}'
  

  Example output

  lvms-operator.v4.22
  

Monitoring LVM Storage

You can monitor LVM Storage by enabling cluster monitoring with a namespace label, then viewing metrics to track storage usage and receiving alerts when thin pool and volume group capacity reaches critical thresholds to prevent data loss.

To enable cluster monitoring, you must add a label in the namespace where you have installed LVM Storage.

Warning

For information about enabling cluster monitoring in RHACM, see "Observability" and "Adding custom metrics".

Procedure

• To enable cluster monitoring, add the following label in the namespace where you have installed LVM Storage:

openshift.io/cluster-monitoring=true

Additional resources

• https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.17/html-single/observability/index[Observability]
• https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.17/html-single/observability/index#adding-custom-metrics[Adding custom metrics]

Metrics and alerts overview

You can monitor thin pool and volume group usage through LVM Storage metrics, and receive alerts at 75% (near full) and 85% (critical) capacity thresholds to take corrective action before storage operations fail.

Metrics

You can monitor LVM Storage by viewing the metrics.

The following table describes the topolvm metrics:

topolvm metrics

Alert	Description
topolvm_thinpool_data_percent	Indicates the percentage of data space used in the LVM thinpool.
topolvm_thinpool_metadata_percent	Indicates the percentage of metadata space used in the LVM thinpool.
topolvm_thinpool_size_bytes	Indicates the size of the LVM thin pool in bytes.
topolvm_volumegroup_available_bytes	Indicates the available space in the LVM volume group in bytes.
topolvm_volumegroup_size_bytes	Indicates the size of the LVM volume group in bytes.
topolvm_thinpool_overprovisioned_available	Indicates the available over-provisioned size of the LVM thin pool in bytes.

Note

Metrics are updated every 10 minutes or when there is a change, such as a new logical volume creation, in the thin pool.

Alerts

When the thin pool and volume group reach maximum storage capacity, further operations fail. This can lead to data loss.

LVM Storage sends the following alerts when the usage of the thin pool and volume group exceeds a certain value:

LVM Storage alerts

Alert	Description
VolumeGroupUsageAtThresholdNearFull	This alert is triggered when both the volume group and thin pool usage exceeds 75% on nodes. Data deletion or volume group expansion is required.
VolumeGroupUsageAtThresholdCritical	This alert is triggered when both the volume group and thin pool usage exceeds 85% on nodes. In this case, the volume group is critically full. Data deletion or volume group expansion is required.
ThinPoolDataUsageAtThresholdNearFull	This alert is triggered when the thin pool data uusage in the volume group exceeds 75% on nodes. Data deletion or thin pool expansion is required.
ThinPoolDataUsageAtThresholdCritical	This alert is triggered when the thin pool data usage in the volume group exceeds 85% on nodes. Data deletion or thin pool expansion is required.
ThinPoolMetaDataUsageAtThresholdNearFull	This alert is triggered when the thin pool metadata usage in the volume group exceeds 75% on nodes. Data deletion or thin pool expansion is required.
ThinPoolMetaDataUsageAtThresholdCritical	This alert is triggered when the thin pool metadata usage in the volume group exceeds 85% on nodes. Data deletion or thin pool expansion is required.

Uninstalling LVM Storage by using the CLI

Uninstall LVM Storage when it is no longer needed or before upgrading to a different storage solution by using the OpenShift CLI (oc) after removing all provisioned storage resources.

Prerequisites

• You have logged in to oc as a user with cluster-admin permissions.
• You deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.
• You deleted the LVMCluster custom resource (CR).

Procedure

1. Get the currentCSV value for the LVM Storage Operator by running the following command:

   $ oc get subscription.operators.coreos.com lvms-operator -n <namespace> -o yaml | grep currentCSV
   

   Example output

   currentCSV: lvms-operator.v4.15.3
   

2. Delete the subscription by running the following command:

   $ oc delete subscription.operators.coreos.com lvms-operator -n <namespace>
   

   Example output

   subscription.operators.coreos.com "lvms-operator" deleted
   

3. Delete the CSV for the LVM Storage Operator in the target namespace by running the following command:

   $ oc delete clusterserviceversion <currentCSV> -n <namespace>
   

   Replace <currentCSV> with the currentCSV value for the LVM Storage Operator.

   Example output

   clusterserviceversion.operators.coreos.com "lvms-operator.v4.15.3" deleted
   

Verification

• To verify that the LVM Storage Operator is uninstalled, run the following command:

  $ oc get csv -n <namespace>
  

  If the LVM Storage Operator was successfully uninstalled, it does not appear in the output of this command.

Uninstalling LVM Storage by using the web console

Uninstall LVM Storage when it is no longer needed or before upgrading to a different storage solution by using the OpenShift Container Platform web console after removing all provisioned storage resources.

Prerequisites

• You have access to OpenShift Container Platform as a user with cluster-admin permissions.
• You have deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.
• You have deleted the LVMCluster custom resource (CR).

Procedure

1. Log in to the OpenShift Container Platform web console.
2. Click Ecosystem → Installed Operators.
3. Click LVM Storage in the openshift-lvm-storage namespace.
4. Click the Details tab.
5. From the Actions menu, select Uninstall Operator.
6. Optional: When prompted, select the Delete all operand instances for this operator checkbox to delete the operand instances for LVM Storage.
7. Click Uninstall.

Uninstalling LVM Storage installed using RHACM

To uninstall LVM Storage that you installed by using RHACM when it is no longer needed or before switching to a different storage solution, delete the RHACM Policy custom resource (CR) that you created for installation after removing all provisioned storage resources.

Prerequisites

• You have access to the RHACM cluster as a user with cluster-admin permissions.
• You have deleted the persistent volume claims (PVCs), volume snapshots, and volume clones provisioned by LVM Storage. You have also deleted the applications that are using these resources.
• You have deleted the LVMCluster CR that you created using RHACM.

Procedure

1. Log in to the OpenShift CLI (oc).

2. Delete the RHACM Policy CR that you created for installing and configuring LVM Storage by using the following command:

   $ oc delete -f <policy> -n <namespace>
   

   Replace <policy> with the name of the Policy CR YAML file.

3. Create a Policy CR YAML file with the configuration to uninstall LVM Storage:

   Example Policy CR to uninstall LVM Storage

   apiVersion: apps.open-cluster-management.io/v1
   kind: PlacementRule
   metadata:
     name: placement-uninstall-lvms
   spec:
     clusterConditions:
     - status: "True"
       type: ManagedClusterConditionAvailable
     clusterSelector:
       matchExpressions:
       - key: mykey
         operator: In
         values:
         - myvalue
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: PlacementBinding
   metadata:
     name: binding-uninstall-lvms
   placementRef:
     apiGroup: apps.open-cluster-management.io
     kind: PlacementRule
     name: placement-uninstall-lvms
   subjects:
   - apiGroup: policy.open-cluster-management.io
     kind: Policy
     name: uninstall-lvms
   ---
   apiVersion: policy.open-cluster-management.io/v1
   kind: Policy
   metadata:
     annotations:
       policy.open-cluster-management.io/categories: CM Configuration Management
       policy.open-cluster-management.io/controls: CM-2 Baseline Configuration
       policy.open-cluster-management.io/standards: NIST SP 800-53
     name: uninstall-lvms
   spec:
     disabled: false
     policy-templates:
     - objectDefinition:
         apiVersion: policy.open-cluster-management.io/v1
         kind: ConfigurationPolicy
         metadata:
           name: uninstall-lvms
         spec:
           object-templates:
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: v1
               kind: Namespace
               metadata:
                 name: openshift-lvm-storage
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: operators.coreos.com/v1
               kind: OperatorGroup
               metadata:
                 name: openshift-storage-operatorgroup
                 namespace: openshift-lvm-storage
               spec:
                 targetNamespaces:
                 - openshift-lvm-storage
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: operators.coreos.com/v1alpha1
               kind: Subscription
               metadata:
                 name: lvms-operator
                 namespace: openshift-lvm-storage
           remediationAction: enforce
           severity: low
     - objectDefinition:
         apiVersion: policy.open-cluster-management.io/v1
         kind: ConfigurationPolicy
         metadata:
           name: policy-remove-lvms-crds
         spec:
           object-templates:
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: apiextensions.k8s.io/v1
               kind: CustomResourceDefinition
               metadata:
                 name: logicalvolumes.topolvm.io
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: apiextensions.k8s.io/v1
               kind: CustomResourceDefinition
               metadata:
                 name: lvmclusters.lvm.topolvm.io
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: apiextensions.k8s.io/v1
               kind: CustomResourceDefinition
               metadata:
                 name: lvmvolumegroupnodestatuses.lvm.topolvm.io
           - complianceType: mustnothave
             objectDefinition:
               apiVersion: apiextensions.k8s.io/v1
               kind: CustomResourceDefinition
               metadata:
                 name: lvmvolumegroups.lvm.topolvm.io
           remediationAction: enforce
           severity: high
   

4. Create the Policy CR by running the following command:

   $ oc create -f <policy> -ns <namespace>
   

Downloading log files and diagnostic information using must-gather

Use the must-gather tool to collect log files and diagnostic information when LVM Storage cannot automatically resolve a problem. You or Red Hat Support can then review the collected data to troubleshoot the issue.

Procedure

• Run the must-gather command from the client connected to the LVM Storage cluster:

  $ oc adm must-gather --image=registry.redhat.io/lvms4/lvms-must-gather-rhel9:v4.22 --dest-dir=<directory_name>
  

Additional resources

• About the must-gather tool

Troubleshooting persistent storage

If persistent storage issues occur with Logical Volume Manager (LVM) Storage, such as persistent volume claims (PVCs) stuck in a pending state, missing components, or node and disk failures, you can diagnose and resolve the problem by reviewing logs and recovering affected resources.

Investigating a PVC stuck in the Pending state

Investigate persistent volume claims (PVCs) stuck in a Pending state to determine whether the cause is insufficient resources, network problems, mismatched storage classes, or unavailable persistent volumes (PVs).

A persistent volume claim (PVC) can get stuck in the Pending state for the following reasons:

• Insufficient computing resources.
• Network problems.
• Mismatched storage class or node selector.
• No available persistent volumes (PVs).
• The node with the PV is in the Not Ready state.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to the OpenShift CLI (oc) as a user with cluster-admin permissions.

Procedure

1. Retrieve the list of PVCs by running the following command:

   $ oc get pvc
   

   Example output

   NAME        STATUS    VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
   lvms-test   Pending                                      lvms-vg1       11s
   

2. Inspect the events associated with a PVC stuck in the Pending state by running the following command:

   $ oc describe pvc <pvc_name>
   

   Replace <pvc_name> with the name of the PVC. For example, lvms-vg1.

   Example output

   Type     Reason              Age               From                         Message
   ----     ------              ----              ----                         -------
   Warning  ProvisioningFailed  4s (x2 over 17s)  persistentvolume-controller  storageclass.storage.k8s.io "lvms-vg1" not found
   

Recovering from a missing storage class

Resolve the "storage class not found" error by verifying that the LVMCluster custom resource (CR) exists and all Logical Volume Manager (LVM) Storage pods are running, then reviewing logs to identify configuration issues.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to the OpenShift CLI (oc) as a user with cluster-admin permissions.

Procedure

1. Verify that the LVMCluster CR is present by running the following command:

   $ oc get lvmcluster -n <namespace>
   

   Example output

   NAME            AGE
   my-lvmcluster   65m
   

2. If the LVMCluster CR is not present, create an LVMCluster CR. For more information, see "Ways to create an LVMCluster custom resource".

3. In the namespace where the operator is installed, check that all the LVM Storage pods are in the Running state by running the following command:

   $ oc get pods -n <namespace>
   

   Example output

   NAME                                  READY   STATUS    RESTARTS      AGE
   lvms-operator-7b9fb858cb-6nsml        3/3     Running   0             70m
   topolvm-controller-5dd9cf78b5-7wwr2   5/5     Running   0             66m
   topolvm-node-dr26h                    4/4     Running   0             66m
   vg-manager-r6zdv                      1/1     Running   0             66m
   

   The output of this command must contain a running instance of the following pods:

   • lvms-operator

   • vg-manager

     If the vg-manager pod is stuck while loading a configuration file, it is due to a failure to locate an available disk for LVM Storage to use. To retrieve the necessary information to troubleshoot this issue, review the logs of the vg-manager pod by running the following command:

     $ oc logs -l app.kubernetes.io/component=vg-manager -n <namespace>
     

Additional resources

• About the LVMCluster custom resource
• Ways to create an LVMCluster custom resource

Recovering from node failure

Identify failed nodes causing persistent volume claims (PVCs) to remain in pending state by examining the restart count of the topolvm-node pod, which indicates potential underlying node problems requiring investigation.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to the OpenShift CLI (oc) as a user with cluster-admin permissions.

Procedure

• Examine the restart count of the topolvm-node pod instances by running the following command:

  $ oc get pods -n <namespace>
  

  Example output

  NAME                                  READY   STATUS    RESTARTS      AGE
  lvms-operator-7b9fb858cb-6nsml        3/3     Running   0             70m
  topolvm-controller-5dd9cf78b5-7wwr2   5/5     Running   0             66m
  topolvm-node-dr26h                    4/4     Running   0             66m
  topolvm-node-54as8                    4/4     Running   0             66m
  topolvm-node-78fft                    4/4     Running   17 (8s ago)   66m
  vg-manager-r6zdv                      1/1     Running   0             66m
  vg-manager-990ut                      1/1     Running   0             66m
  vg-manager-an118                      1/1     Running   0             66m
  

Next steps

If the PVC is stuck in the Pending state even after you have resolved any issues with the node, you must perform a forced clean-up. For more information, see "Performing a forced clean-up".

Additional resources

• Performing a forced clean-up

Recovering from disk failure

Diagnose and resolve disk and volume provisioning failures by inspecting persistent volume claim (PVC) events to identify specific error messages, then connecting to the affected host to fix the underlying disk issue.

Disk and volume provisioning issues result with a generic error message such as Failed to provision volume with storage class <storage_class_name>. The generic error message is followed by a specific volume failure error message.

The following table describes the volume failure error messages:

Volume failure error messages

Error message	Description
Failed to check volume existence	Indicates a problem in verifying whether the volume already exists. Volume verification failure can be caused by network connectivity problems or other failures.
Failed to bind volume	Failure to bind a volume can happen if the persistent volume (PV) that is available does not match the requirements of the PVC.
FailedMount or FailedAttachVolume	This error indicates problems when trying to mount the volume to a node. If the disk has failed, this error can appear when a pod tries to use the PVC.
FailedUnMount	This error indicates problems when trying to unmount a volume from a node. If the disk has failed, this error can appear when a pod tries to use the PVC.
Volume is already exclusively attached to one node and cannot be attached to another	This error can appear with storage solutions that do not support ReadWriteMany access modes.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to the OpenShift CLI (oc) as a user with cluster-admin permissions.

Procedure

1. Inspect the events associated with a PVC by running the following command:

   $ oc describe pvc <pvc_name>
   

   Replace <pvc_name> with the name of the PVC.

2. Establish a direct connection to the host where the problem is occurring.

3. Resolve the disk issue.

Next steps

If the volume failure messages persist or recur even after you have resolved the issue with the disk, you must perform a forced clean-up. For more information, see "Performing a forced clean-up".

Additional resources

• Performing a forced clean-up

Performing a forced clean-up

Perform a forced clean-up by removing all Logical Volume Manager (LVM) Storage custom resources (CRs) when disk or node-related problems continue after standard troubleshooting, to restore proper storage functioning.

If the disk or node-related problems persist even after you have completed the troubleshooting procedures, you must perform a forced clean-up. A forced clean-up is used to address persistent issues and ensure the proper functioning of LVM Storage.

Prerequisites

• You have installed the OpenShift CLI (oc).
• You have logged in to the OpenShift CLI (oc) as a user with cluster-admin permissions.
• You have deleted all the persistent volume claims (PVCs) that were created by using LVM Storage.
• You have stopped the pods that are using the PVCs that were created by using LVM Storage.

Procedure

1. Switch to the namespace where you have installed the LVM Storage Operator by running the following command:

   $ oc project <namespace>
   

2. Check if the LogicalVolume custom resources are present by running the following command:

   $ oc get logicalvolume
   

   1. If the LogicalVolume CRs are present, delete them by running the following command:

      $ oc delete logicalvolume <name>
      

      Replace <name> with the name of the LogicalVolume CR.

   2. After deleting the LogicalVolume CRs, remove their finalizers by running the following command:

      $ oc patch logicalvolume <name> -p '{"metadata":{"finalizers":[]}}' --type=merge
      

      Replace <name> with the name of the LogicalVolume CR.

3. Check if the LVMVolumeGroup CRs are present by running the following command:

   $ oc get lvmvolumegroup
   

   1. If the LVMVolumeGroup CRs are present, delete them by running the following command:

      $ oc delete lvmvolumegroup <name>
      

      Replace <name> with the name of the LVMVolumeGroup CR.

   2. After deleting the LVMVolumeGroup CRs, remove their finalizers by running the following command:

      $ oc patch lvmvolumegroup <name> -p '{"metadata":{"finalizers":[]}}' --type=merge
      

      Replace <name> with the name of the LVMVolumeGroup CR.

4. Delete any LVMVolumeGroupNodeStatus CRs by running the following command:

   $ oc delete lvmvolumegroupnodestatus --all
   

5. Delete the LVMCluster CR by running the following command:

   $ oc delete lvmcluster --all
   

   1. After deleting the LVMCluster CR, remove its finalizer by running the following command:

      $ oc patch lvmcluster <name> -p '{"metadata":{"finalizers":[]}}' --type=merge
      

      Replace <name> with the name of the LVMCluster CR.

Additional resources

• Red Hat Advanced Cluster Management for Kubernetes: Installing while connected online