--- title: Deploying on OpenStack with rootVolume and etcd on local disk --- # Deploying on OpenStack with rootVolume and etcd on local disk {#deploying-openstack-on-local-disk} After installation, you can resolve and prevent performance issues of your Red Hat OpenStack Platform (RHOSP) installation by moving etcd from a root volume (provided by RHOSP Cinder) to a dedicated ephemeral local disk. ## Deploying OpenStack on local disk {#installation-osp-local-disk-deployment_deploying-openstack-on-local-disk} If you have an existing RHOSP cloud, you can move etcd from that cloud to a dedicated ephemeral local disk. **Prerequisites** - You have an RHOSP cloud with a working Cinder. - Your RHOSP cloud has at least 75 GB of available storage to accommodate 3 root volumes for the OpenShift control plane. - The RHOSP cloud is deployed with Nova ephemeral storage that uses a local storage backend and not `rbd`. **Procedure** 1. Create a Nova flavor for the control plane with at least 10 GB of ephemeral disk. Replace the values for `--ram`, `--disk`, and `` based on your environment. ```terminal $ openstack flavor create -- -- --ephemeral 10 --vcpus 4 ``` 2. Deploy a cluster with root volumes for the control plane; for example: ```yaml {title="Example YAML file"} # ... controlPlane: name: master platform: openstack: type: ${CONTROL_PLANE_FLAVOR} rootVolume: size: 25 types: - ${CINDER_TYPE} replicas: 3 # ... ``` 3. Deploy the cluster you created by running the following command: ```terminal $ openshift-install create cluster --dir ``` For ``, specify the location of the customized `./install-config.yaml file` that you previously created. 4. Verify that the cluster you deployed is healthy before proceeding to the next step by running the following command: ```terminal $ oc wait clusteroperators --all --for=condition=Progressing=false ``` Check the output and ensure that the cluster Operators are finished progressing and that the cluster is not deploying or updating. 5. Create a file named `98-var-lib-etcd.yaml` by using the following YAML file: ```yaml apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfig metadata: labels: machineconfiguration.openshift.io/role: master name: 98-var-lib-etcd spec: config: ignition: version: 3.5.0 systemd: units: - contents: | [Unit] Description=Mount local-etcd to /var/lib/etcd [Mount] What=/dev/disk/by-label/local-etcd Where=/var/lib/etcd Type=xfs Options=defaults,prjquota [Install] WantedBy=local-fs.target enabled: true name: var-lib-etcd.mount - contents: | [Unit] Description=Create local-etcd filesystem DefaultDependencies=no After=local-fs-pre.target ConditionPathIsSymbolicLink=!/dev/disk/by-label/local-etcd [Service] Type=oneshot RemainAfterExit=yes ExecStart=/bin/bash -c "[ -L /dev/disk/by-label/ephemeral0 ] || ( >&2 echo Ephemeral disk does not exist; /usr/bin/false )" ExecStart=/usr/sbin/mkfs.xfs -f -L local-etcd /dev/disk/by-label/ephemeral0 [Install] RequiredBy=dev-disk-by\x2dlabel-local\x2detcd.device enabled: true name: create-local-etcd.service - contents: | [Unit] Description=Migrate existing data to local etcd After=var-lib-etcd.mount Before=crio.service Requisite=var-lib-etcd.mount ConditionPathExists=!/var/lib/etcd/member ConditionPathIsDirectory=/sysroot/ostree/deploy/rhcos/var/lib/etcd/member [Service] Type=oneshot RemainAfterExit=yes ExecStart=/bin/bash -c "if [ -d /var/lib/etcd/member.migrate ]; then rm -rf /var/lib/etcd/member.migrate; fi" ExecStart=/usr/bin/cp -aZ /sysroot/ostree/deploy/rhcos/var/lib/etcd/member/ /var/lib/etcd/member.migrate ExecStart=/usr/bin/mv /var/lib/etcd/member.migrate /var/lib/etcd/member [Install] RequiredBy=var-lib-etcd.mount enabled: true name: migrate-to-local-etcd.service - contents: | [Unit] Description=Relabel /var/lib/etcd After=migrate-to-local-etcd.service Before=crio.service Requisite=var-lib-etcd.mount [Service] Type=oneshot RemainAfterExit=yes ExecCondition=/bin/bash -c "[ -n \"$(restorecon -nv /var/lib/etcd)\" ]" ExecStart=/usr/sbin/restorecon -R /var/lib/etcd [Install] RequiredBy=var-lib-etcd.mount enabled: true name: relabel-var-lib-etcd.service ``` where: `[Mount].What=/dev/disk/by-label/local-etcd` : Specifies the etcd database must be mounted by the device, not a label, to ensure that `systemd` generates the device dependency used in this config to trigger filesystem creation. `[Unit].ConditionPathIsSymbolicLink=!/dev/disk/by-label/local-etcd` : Do not run if the file system `dev/disk/by-label/local-etcd` already exists. `[Service].ExecStart=/usr/sbin/mkfs.xfs` : Fails with an alert message if `/dev/disk/by-label/ephemeral0` does not exist. `[Unit].Before=crio.service` : Migrates existing data to local etcd database. This config does so after `/var/lib/etcd` is mounted, but before CRI-O starts so etcd is not running yet. `[Unit].ConditionPathIsDirectory` : Requires that etcd is mounted and does not contain a member directory, but the ostree does. `[Service].ExecStart=/bin/bash` : Cleans up any previous migration state. `[Service].ExecStart=/usr/bin/mv` : Copies and moves in separate steps to ensure atomic creation of a complete member directory. `[Service].ExecCondition=/bin/bash` : Performs a quick check of the mount point directory before performing a full recursive relabel. If restorecon in the file path `/var/lib/etcd` cannot rename the directory, the recursive rename is not performed. > [!WARNING] > After you apply the `98-var-lib-etcd.yaml` file to the system, do not remove the file. Removing this file will break etcd members and lead to system instability. > > If a rollback is necessary, modify the `ControlPlaneMachineSet` object to use a flavor that does not include ephemeral disks. This change regenerates the control plane nodes without using ephemeral disks for the etcd partition, which avoids issues related to the `98-var-lib-etcd.yaml` file. You can safely remove the `98-var-lib-etcd.yaml` file only after the update to the `ControlPlaneMachineSet` object is complete and no control plane nodes are using ephemeral disks. 6. Create the new `MachineConfig` object by running the following command: ```terminal $ oc create -f 98-var-lib-etcd.yaml ``` > [!NOTE] > Moving the etcd database onto the local disk of each control plane machine takes time. 7. Verify that the etcd databases has been transferred to the local disk of each control plane by running the following commands: 1. Verify that the cluster is still updating by running the following command: ```terminal $ oc wait --timeout=45m --for=condition=Updating=false machineconfigpool/master ``` 2. Verify that the cluster is ready by running the following command: ```terminal $ oc wait node --selector='node-role.kubernetes.io/master' --for condition=Ready --timeout=30s ``` 3. Verify that the cluster Operators are running in the cluster by running the following command: ```terminal $ oc wait clusteroperators --timeout=30m --all --for=condition=Progressing=false ``` **Additional resources** {._additional-resources} - [Recommended etcd practices](/openshift-docs-markdown/etcd/etcd-practices#recommended-etcd-practices) - [Overview of backup and restore options](/openshift-docs-markdown/backup_and_restore/index#backup-restore-operations-overview)