Chapter 6. Replacing nodes

Procedure

1. Check the labels on the failed node and make note of the rack label.

   $ oc get nodes --show-labels | grep failed-node-name

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2. Identify the mon (if any) and object storage device (OSD) pods that are running in the failed node.

   $ oc get pods -n openshift-storage -o wide | grep -i failed-node-name

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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=failed-node-name  --replicas=0 -n openshift-storage

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4. Mark the failed node so that it cannot be scheduled for work.

   $ oc adm cordon failed-node-name

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5. Drain the failed node of existing work.

   $ oc adm drain failed-node-name --force --delete-local-data --ignore-daemonsets

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   Note

   If the failed node is not connected to the network, remove the pods running on it by using the command:

   $ oc get pods -A -o wide | grep -i failed-node-name |  awk '{if ($4 == "Terminating") system ("oc -n " $1 " delete pods " $2  " --grace-period=0 " " --force ")}'
   $ oc adm drain failed-node-name --force --delete-local-data --ignore-daemonsets

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6. Delete the failed node.

   $ oc delete node failed-node-name

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

9. Check for certificate signing requests (CSRs) related to OpenShift Container Storage that are in Pending state:

   $ oc get csr

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10. Approve all required OpenShift Container Storage CSRs for the new node:

    $ oc adm certificate approve certificate-name

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11. Click Compute Nodes in OpenShift Web Console, confirm if the new node is in Ready state.

12. Apply the OpenShift Container Storage label to the new node using your preferred interface:

    • From OpenShift web console

      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. Execute the following command to apply the OpenShift Container Storage label to the new node:

         $ oc label node new-node-name cluster.ocs.openshift.io/openshift-storage=""

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13. Add the local storage devices available in these worker nodes to the OpenShift Container Storage StorageCluster.

    1. Determine which localVolumeSet to edit.

       Replace local-storage-project in the following commands with the name of your local storage project. The default project name is openshift-local-storage in OpenShift Container Storage 4.6 and later. Previous versions use local-storage by default.

       # oc get -n local-storage-project localvolumeset
       NAME           AGE
       localblock    25h

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    2. Update the localVolumeSet definition to include the new node and remove the failed node.

       # oc edit -n local-storage-project localvolumeset localblock
       [...]
           nodeSelector:
           nodeSelectorTerms:
             - matchExpressions:
                 - key: kubernetes.io/hostname
                   operator: In
                   values:
                   #- worker-0
                   - worker-1
                   - worker-2
                   - worker-3
       [...]

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       Remember to save before exiting the editor.

14. Verify that the new localblock PV is available.

    $ oc get pv | grep localblock
    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

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15. Change to the openshift-storage project.

    $ oc project openshift-storage

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

    1. Identify the PVC as afterwards we need to delete PV associated with that specific 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

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       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

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       In this example, the PVC name is ocs-deviceset-localblock-0-data-0-g2mmc.

    2. Remove the failed OSD from the cluster.

       # oc process -n openshift-storage ocs-osd-removal -p FAILED_OSD_IDS=${osd_id_to_remove},{osd_id_to_remove2} | oc create -f -

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17. Verify that the OSD is removed successfully by checking the status of the ocs-osd-removal pod.

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

    # oc get pod -l job-name=ocs-osd-removal-${osd_id_to_remove} -n openshift-storage

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    Note

    If ocs-osd-removal 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-${osd_id_to_remove} -n openshift-storage --tail=-1

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18. Delete the PV associated with the failed node.

    1. Identify the PV associated with the PVC.

       # oc get -n openshift-storage pvc ocs-deviceset-<x>-<y>-<pvc-suffix>

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       where, x, y, and pvc-suffix are the values in the DeviceSet identified in the previous step.

       For example:

       # oc get -n openshift-storage pvc ocs-deviceset-localblock-0-data-0-g2mmc
       NAME                      STATUS        VOLUME        CAPACITY   ACCESS MODES   STORAGECLASS   AGE
       ocs-deviceset-localblock-0-data-0-g2mmc   Bound   local-pv-5c9b8982   500Gi      RWO            localblock     24h

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       In this example, the associated PV is local-pv-5c9b8982.

    2. Delete the PV.

       # oc delete pv <persistent-volume>

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       For example:

       # oc delete pv local-pv-5c9b8982
       persistentvolume "local-pv-5c9b8982" deleted

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19. Delete the crashcollector pod deployment.

    $ oc delete deployment --selector=app=rook-ceph-crashcollector,node_name=failed-node-name -n openshift-storage

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20. Deploy the new OSD by restarting the rook-ceph-operator to force operator reconciliation.

    # oc get -n openshift-storage pod -l app=rook-ceph-operator

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    Example output:

    NAME                                  READY   STATUS    RESTARTS   AGE
    rook-ceph-operator-77758ddc74-dlwn2   1/1     Running   0          1d20h

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    1. Delete the rook-ceph-operator.

       # oc delete -n openshift-storage pod rook-ceph-operator-77758ddc74-dlwn2

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       Example output:

       pod "rook-ceph-operator-77758ddc74-dlwn2" deleted

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21. Verify that the rook-ceph-operator pod is restarted.

    # oc get -n openshift-storage pod -l app=rook-ceph-operator

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    Example output:

    NAME                                  READY   STATUS    RESTARTS   AGE
    rook-ceph-operator-77758ddc74-wqf25   1/1     Running   0          66s

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    Creation of the new OSD and mon might take several minutes after the operator restarts.

22. Delete the ocs-osd-removal job.

    # oc delete job ocs-osd-removal-${osd_id_to_remove}

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    For example:

    # oc delete job ocs-osd-removal-1
    job.batch "ocs-osd-removal-1" deleted

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