2.3. Replacing storage nodes on IBM Power infrastructure

Procedure

1. Identify the node, and get the labels on the node that you need to replace:

   $ oc get nodes --show-labels | grep <node_name>

   <node_name>

   Specify the name of node that you need to replace.

2. Identify the mon (if any), and Object Storage Device (OSD) pods that are running in the node that you need to replace:

   $ oc get pods -n openshift-storage -o wide | grep -i <node_name>

3. Scale down the deployments of the pods identified in the previous step:

   For example:

   $ oc scale deployment rook-ceph-mon-a --replicas=0 -n openshift-storage

   $ oc scale deployment rook-ceph-osd-1 --replicas=0 -n openshift-storage

   $ oc scale deployment --selector=app=rook-ceph-crashcollector,node_name=<node_name> --replicas=0 -n openshift-storage

4. Mark the node as unschedulable:

   $ oc adm cordon <node_name>

5. Remove the pods which are in Terminating state:

   $ oc get pods -A -o wide | grep -i <node_name> |  awk '{if ($4 == "Terminating") system ("oc -n " $1 " delete pods " $2  " --grace-period=0 " " --force ")}'

6. Drain the node:

   $ oc adm drain <node_name> --force --delete-emptydir-data=true --ignore-daemonsets

7. Delete the node:

   $ oc delete node <node_name>

8. Get a new IBM Power machine with the required infrastructure. See Installing a cluster on IBM Power.
9. Create a new OpenShift Container Platform node using the new IBM Power machine.

10. Check for the Certificate Signing Requests (CSRs) related to OpenShift Container Platform that are in Pending state:

    $ oc get csr

11. Approve all the required OpenShift Container Platform CSRs for the new node:

    $ oc adm certificate approve <certificate_name>

    <certificate_name>

    Specify the name of the CSR.

12. Click Compute Nodes in the OpenShift Web Console. Confirm that the new node is in Ready state.

13. Apply the OpenShift Data Foundation label to the new node using any one of the following:

    From the user interface

    1. For the new node, click Action Menu (⋮) Edit Labels.
    2. Add cluster.ocs.openshift.io/openshift-storage, and click Save.

    From the command-line interface

    1. Apply the OpenShift Data Foundation label to the new node:

    $ oc label node <new_node_name> cluster.ocs.openshift.io/openshift-storage=''

    <new_node_name>

    Specify the name of the new node.

14. Identify the namespace where OpenShift local storage operator is installed, and assign it to the local_storage_project variable:

    $ local_storage_project=$(oc get csv --all-namespaces | awk '{print $1}' | grep local)

    For example:

    $ local_storage_project=$(oc get csv --all-namespaces | awk '{print $1}' | grep local)

    echo $local_storage_project

    Example output:

    openshift-local-storage

15. Add a newly added worker node to the localVolume.

    1. Determine the localVolume you need to edit:

       # oc get -n $local_storage_project localvolume

       Example output:

       NAME           AGE
       localblock    25h

    2. Update the localVolume definition to include the new node, and remove the failed node:

       # oc edit -n $local_storage_project localvolume localblock

       Example output:

       [...]
           nodeSelector:
           nodeSelectorTerms:
             - matchExpressions:
                 - key: kubernetes.io/hostname
                   operator: In
                   values:
                   #- worker-0
                   - worker-1
                   - worker-2
                   - worker-3
       [...]

       Remember to save before exiting the editor.

       In the this example, worker-0 is removed and worker-3 is the new node.

16. Verify that the new localblock Persistent Volume (PV) is available:

    $ oc get pv | grep localblock

    Example output:

    NAME              CAPACITY   ACCESSMODES RECLAIMPOLICY STATUS     CLAIM             STORAGECLASS                 AGE
    local-pv-3e8964d3    500Gi    RWO         Delete       Bound      ocs-deviceset-localblock-2-data-0-mdbg9  localblock     25h
    local-pv-414755e0    500Gi    RWO         Delete       Bound      ocs-deviceset-localblock-1-data-0-4cslf  localblock     25h
    local-pv-b481410    500Gi     RWO        Delete       Available                                            localblock     3m24s
    local-pv-5c9b8982    500Gi    RWO         Delete       Bound      ocs-deviceset-localblock-0-data-0-g2mmc  localblock     25h

17. Navigate to the openshift-storage project:

    $ oc project openshift-storage

18. Remove the failed OSD from the cluster. You can specify multiple failed OSDs if required.

    1. Identify the Persistent Volume Claim (PVC):

       $ osd_id_to_remove=1

       $ oc get -n openshift-storage -o yaml deployment rook-ceph-osd-${<osd_id_to_remove>} | grep ceph.rook.io/pvc

       where, <osd_id_to_remove> is the integer in the pod name immediately after the rook-ceph-osd prefix.

       In this example, the deployment name is rook-ceph-osd-1.

       Example output:

       ceph.rook.io/pvc: ocs-deviceset-localblock-0-data-0-g2mmc
           ceph.rook.io/pvc: ocs-deviceset-localblock-0-data-0-g2mmc

    2. Remove the failed OSD from the cluster. You can specify multiple failed OSDs if required:

       $ oc process -n openshift-storage ocs-osd-removal \
       -p FAILED_OSD_IDS=<failed_osd_id> | oc create -f -

       <failed_osd_id>

       Is the integer in the pod name immediately after the rook-ceph-osd prefix. You can add comma separated OSD IDs in the command to remove more than one OSD, for example, FAILED_OSD_IDS=0,1,2.

       The FORCE_OSD_REMOVAL value must be changed to true in clusters that only have three OSDs, or clusters with insufficient space to restore all three replicas of the data after the OSD is removed.

       주의

       This step results in the OSD being completely removed from the cluster. Ensure that the correct value of osd_id_to_remove is provided.

19. Verify that the OSD was removed successfully by checking the status of the ocs-osd-removal-job pod.

    A status of Completed confirms that the OSD removal job has succeeded.

    # oc get pod -l job-name=ocs-osd-removal-job -n openshift-storage

20. Ensure that the OSD removal is completed.

    $ oc logs -l job-name=ocs-osd-removal-job -n openshift-storage --tail=-1 | egrep -i 'completed removal'

    Example output:

    2022-05-10 06:50:04.501511 I | cephosd: completed removal of OSD 0

    중요

    If the ocs-osd-removal-job fails, and the pod is not in the expected Completed state, check the pod logs for further debugging.

    For example:

    # oc logs -l job-name=ocs-osd-removal-job -n openshift-storage --tail=-1

21. Delete the PV associated with the failed node.

    1. Identify the PV associated with the PVC:

       # oc get pv -L kubernetes.io/hostname | grep localblock | grep Released

       Example output:

       local-pv-5c9b8982  500Gi  RWO  Delete  Released  openshift-storage/ocs-deviceset-localblock-0-data-0-g2mmc  localblock  24h  worker-0

       The PVC name must be identical to the name that is obtained while removing the failed OSD from the cluster.

    2. If there is a PV in Released state, delete it:

       # oc delete pv <persistent_volume>

       For example:

       # oc delete pv local-pv-5c9b8982

       Example output:

       persistentvolume "local-pv-5c9b8982" deleted

22. Identify the crashcollector pod deployment:

    $ oc get deployment --selector=app=rook-ceph-crashcollector,node_name=<failed_node_name> -n openshift-storage

    If there is an existing crashcollector pod deployment, delete it:

    $ oc delete deployment --selector=app=rook-ceph-crashcollector,node_name=<failed_node_name> -n openshift-storage

23. Delete the ocs-osd-removal-job:

    # oc delete -n openshift-storage job ocs-osd-removal-job

    Example output:

    job.batch "ocs-osd-removal-job" deleted

Verification steps

1. Verify that the new node is present in the output:

   $ oc get nodes --show-labels | grep cluster.ocs.openshift.io/openshift-storage= |cut -d' ' -f1

2. Click Workloads Pods. Confirm that at least the following pods on the new node are in Running state:

   • csi-cephfsplugin-*
   • csi-rbdplugin-*

3. Verify that all other required OpenShift Data Foundation pods are in Running state.

   Ensure that the new incremental mon is created and is in the Running state:

   $ oc get pod -n openshift-storage | grep mon

   Example output:

   rook-ceph-mon-b-74f6dc9dd6-4llzq                                   1/1     Running     0          6h14m
   rook-ceph-mon-c-74948755c-h7wtx                                    1/1     Running     0          4h24m
   rook-ceph-mon-d-598f69869b-4bv49                                   1/1     Running     0          162m

   The OSD and monitor pod might take several minutes to get to the Running state.

4. Verify that the new OSD pods are running on the replacement node:

   $ oc get pods -o wide -n openshift-storage| egrep -i <new_node_name> | egrep osd

5. Optional: If cluster-wide encryption is enabled on the cluster, verify that the new OSD devices are encrypted.

   For each of the new nodes identified in the previous step, do the following:

   1. Create a debug pod and open a chroot environment for the one or more selected hosts:

      $ oc debug node/<node_name>

      $ chroot /host

   2. Display the list of available block devices:

      $ lsblk

      Check for the crypt keyword beside the one or more ocs-deviceset names.

6. If the verification steps fail, contact Red Hat Support.