--- title: Creating custom machine config pools --- # Creating custom machine config pools {#machine-config-creating-custom-mcp} You can create custom machine config pools (MCP) to manage compute nodes for custom use cases that extend outside of the default node types. By using a custom machine config pool, you can deploy changes targeted only at nodes in the custom pool. Custom machine config pools inherit their configurations from the `worker` machine config pool. Changes made to the `worker` machine config pool apply to nodes in the custom pool. However, changes made to the custom machine config pool apply only to the nodes in the custom pool. For more information on custom machine config pools, see "Node configuration management with machine config pools". > [!NOTE] > Custom machine config pools for the control plane nodes are not supported. For example, you could use a custom machine config pool to create an *infrastructure* node. Components that you move to an infrastructure node do not need to be accounted for during sizing. For more information on infrastructure nodes, see "Creating infrastructure machine sets". After you create the custom machine config pool, you can boot new nodes directly to the pool by creating a new machine set. Or, you can add existing nodes to the custom pool by using labels. ## Creating a custom machine config pool with a new node {#machine-config-custom-mcp-automatic_machine-config-creating-custom-mcp} You can create a custom machine config pool (MCP) and launch a new node directly into that pool. By launching the node directly into the new pool, you save a node reboot cycle that would be required when moving the nodes from the worker machine config pool to the custom pool. Use the `userDataSecret` parameter in the machine set to instruct the Machine Config Operator (MCO) to add the node to a specific machine config pool. The secret contains the endpoint of the custom machine config pool. You must prefix the name of this new secret with the name of the custom machine config pool. The following procedure shows you how to create a new custom machine config pool and launch a new node into that pool. **Procedure** 1. Create a custom machine config pool: 1. Create a YAML file similar to the following: ```yaml apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfigPool metadata: name: custom spec: machineConfigSelector: matchExpressions: - {key: machineconfiguration.openshift.io/role, operator: In, values: [custom,worker]} nodeSelector: matchLabels: node-role.kubernetes.io/custom: "" ``` where: `metadata.name` : Specifies a name for the custom machine config pool. `spec.machineConfigSelector.matchExpressions` : Specifies the node roles for the new node. This must include the `worker` role and the custom role. `spec.nodeSelector.matchLabels` : Specifies a node selector to use when adding nodes to this pool. 2. Create the machine config pool by running the following command: ```terminal $ oc create -f .yaml ``` 2. Create a new machine set that creates a new node in the new custom machine config pool: 1. Create a YAML file, for example by making a copy of an existing compute machine set YAML and making the following changes: ```yaml apiVersion: machine.openshift.io/v1beta1 kind: MachineSet metadata: # ... name: namespace: openshift-machine-api # ... spec: # ... template: # ... spec: # ... providerSpec: # ... value: # ... userDataSecret: name: -user-data-managed # ... ``` where: `metadata.name` : Specifies a name for the machine set. `metadata.namespace` : Specifies a namespace for the machine set. This must be `openshift-machine-api`. `spec.template.spec.providerSpec.value.userDataSecret` : Specifies a name for the user data secret that is created. The name of the secret must start with the name of the custom machine config pool and end with `-user-data-managed`. For example `custom-user-data-managed`. These are the minimum changes required to create the new machine set. For more configuration options or to configure an all-new machine set, see "Creating infrastructure machine sets" for your platform. > [!NOTE] > When creating a new machine set, you should specify the latest image to use for the boot image. For more information about configuring the boot image on your cluster, see "Manually updating the boot image" for your platform. The method to specify the image varies by provider. 2. Create the machine set by running the following command: ```terminal $ oc create -f .yaml ``` The MCO creates a new node in the new custom machine config pool. **Verification** 1. Check to see that the MCO created the new machine config pool by running the following command: ```terminal $ oc get mcp ``` ```terminal {title="Example output"} NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE custom rendered-custom-72be15c95699b6d39f70fce525f51bb2 True False False 1 1 1 0 12s master rendered-master-9e25b616b551d6c77f490191f45161d7 True False False 3 3 3 0 32m worker rendered-worker-72be15c95699b6d39f70fce525f51bb2 True False False 2 2 2 0 32m ``` In this example, `custom` is the new machine config pool. 2. Check to see that the MCO created the new machine set by running the following command: ```terminal $ oc get machineset -n openshift-machine-api ``` ```terminal {title="Example output"} NAME DESIRED CURRENT READY AVAILABLE AGE ci-ln-7x179fk-72292-tc5qz-custom-a 1 1 1 1 62s ci-ln-7x179fk-72292-tc5qz-worker-a 1 1 1 1 91m ci-ln-7x179fk-72292-tc5qz-worker-b 1 1 1 1 91m ci-ln-7x179fk-72292-tc5qz-worker-f 1 1 1 1 91m ``` In this example, `ci-ln-7x179fk-72292-tc5qz-custom-a` is the new machine set. 3. Check that the MCO created the required secret by running the following command: ```terminal $ oc get secrets -n openshift-machine-api ``` ```terminal {title="Example output"} NAME TYPE DATA AGE # ... custom-user-data-managed Opaque 2 9m # ... ``` 4. Check to see that the node is in the new custom machine config pool by running the following command: ```terminal $ oc get nodes ``` ```terminal {title="Example output"} NAME STATUS ROLES AGE VERSION ci-ln-i61xqwb-72292-hz2mw-custom-9r496 Ready custom,worker 9m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-master-0 Ready control-plane,master 42m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-master-1 Ready control-plane,master 44m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-master-2 Ready control-plane,master 43m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-worker-c-2lhcl Ready worker 36m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-worker-f-qgdb7 Ready worker 36m v1.35.3 ``` In this example, the `ci-ln-i61xqwb-72292--hz2mw-custom-9r496` is a new node that was added to the `custom` machine config pool. ## Creating a custom machine config pool for an existing node {#machine-config-custom-mcp-existing_machine-config-creating-custom-mcp} You can create custom machine config pools (MCP) and manually add an existing node into that pool. With custom machine config pools, you can deploy changes targeted at the nodes in the custom pool. The following procedure shows you how to create a new custom machine config pool and add an existing node into that pool. **Procedure** 1. Create a custom machine config pool: 1. Create a YAML file similar to the following: ```yaml apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfigPool metadata: name: custom spec: machineConfigSelector: matchExpressions: - {key: machineconfiguration.openshift.io/role, operator: In, values: [custom,worker]} nodeSelector: matchLabels: node-role.kubernetes.io/custom: "" ``` where: `metadata.name` : Specifies a name for the machine config pool. `spec.machineConfigSelector.matchExpressions` : Specifies the node roles for the new node. This must include the `worker` role and the custom role. `spec.nodeSelector.matchLabels` : Specifies a node selector to use when adding nodes to this pool. 2. Create the machine config pool by running the following command: ```terminal $ oc create -f .yaml ``` 2. Add a label to the worker nodes that you want to move to the new custom pool by running the following command: ```terminal $ oc label node ``` Replace `` with the name of the node that you want to move and replace `` with the node selector you added to the machine config pool. ```terminal {title="Example command"} $ oc label node ci-ln-g5tpp5k-72292-hz2mw-worker-b-ps8xh node-role.kubernetes.io/custom="" ``` **Verification** 1. Check to see that the MCO created the new machine config pool by running the following command: ```terminal $ oc get mcp ``` ```terminal {title="Example output"} NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE custom rendered-custom-72be15c95699b6d39f70fce525f51bb2 True False False 1 1 1 0 12s master rendered-master-9e25b616b551d6c77f490191f45161d7 True False False 3 3 3 0 32m worker rendered-worker-72be15c95699b6d39f70fce525f51bb2 True False False 2 2 2 0 32m ``` In this example, `custom` is the new machine config pool. 2. Check to see if the node is in that pool by running the following command: ```terminal $ oc get nodes ``` ```terminal {title="Example output"} NAME STATUS ROLES AGE VERSION ci-ln-i61xqwb-72292-ftjn8-master-0 Ready control-plane,master 42m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-master-1 Ready control-plane,master 44m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-master-2 Ready control-plane,master 43m v1.35.3 ci-ln-g5tpp5k-72292-hz2mw-worker-b-ps8xh Ready custom,worker 36m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-worker-c-2lhcl Ready worker 36m v1.35.3 ci-ln-i61xqwb-72292-ftjn8-worker-f-qgdb7 Ready worker 36m v1.35.3 ``` In this example, the `ci-ln-g5tpp5k-72292-hz2mw-worker-b-ps8xh` node is an existing node that was moved to the `custom` machine config pool. **Additional resources** {._additional-resources} - [Node configuration management with machine config pools](/openshift-docs-markdown/machine_configuration/index#architecture-machine-config-pools_machine-config-overview) - [Manually updating the boot image](/openshift-docs-markdown/machine_configuration/mco-update-boot-images-manual#mco-update-boot-images-manual) - [Creating infrastructure machine sets](/openshift-docs-markdown/machine_management/creating-infrastructure-machinesets#creating-infrastructure-machinesets)