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Persistent Storage

This guide is to help users debug any general storage issues when deploying charts in this repository.

Ceph

Ceph Deployment Status

First, we want to validate that Ceph is working correctly. This can be done with the following Ceph command:

admin@kubenode01:~$ MON_POD=$(kubectl get --no-headers pods -n=ceph -l="application=ceph,component=mon" | awk '{ print $1; exit }')
admin@kubenode01:~$ kubectl exec -n ceph ${MON_POD} -- ceph -s
    cluster:
      id:     06a191c7-81bd-43f3-b5dd-3d6c6666af71
      health: HEALTH_OK

    services:
      mon: 1 daemons, quorum att.port.direct
      mgr: att.port.direct(active)
      mds: cephfs-1/1/1 up  {0=mds-ceph-mds-68c9c76d59-zqc55=up:active}
      osd: 1 osds: 1 up, 1 in
      rgw: 1 daemon active

    data:
      pools:   11 pools, 208 pgs
      objects: 352 objects, 464 MB
      usage:   62467 MB used, 112 GB / 173 GB avail
      pgs:     208 active+clean

    io:
      client:   253 B/s rd, 39502 B/s wr, 1 op/s rd, 8 op/s wr
admin@kubenode01:~$

Use one of your Ceph Monitors to check the status of the cluster. A couple of things to note above; our health is HEALTH_OK, we have 3 mons, we’ve established a quorum, and we can see that all of our OSDs are up and in the OSD map.

PVC Preliminary Validation

Before proceeding, it is important to ensure that you have deployed a client key in the namespace you wish to fulfill PersistentVolumeClaims. To verify that your deployment namespace has a client key:

admin@kubenode01: $ kubectl get secret -n openstack pvc-ceph-client-key
NAME                  TYPE                DATA      AGE
pvc-ceph-client-key   kubernetes.io/rbd   1         8h

Without this, your RBD-backed PVCs will never reach the Bound state. For more information, see how to activate namespace for ceph.

Note: This step is not relevant for PVCs within the same namespace Ceph was deployed.

Ceph Validating PVC Operation

To validate persistent volume claim (PVC) creation, we’ve placed a test manifest here. Deploy this manifest and verify the job completes successfully.

Ceph Validating StorageClass

Next we can look at the storage class, to make sure that it was created correctly:

admin@kubenode01:~$ kubectl describe storageclass/general
Name:            general
IsDefaultClass:  No
Annotations:     <none>
Provisioner:     ceph.com/rbd
Parameters:      adminId=admin,adminSecretName=pvc-ceph-conf-combined-storageclass,adminSecretNamespace=ceph,imageFeatures=layering,imageFormat=2,monitors=ceph-mon.ceph.svc.cluster.local:6789,pool=rbd,userId=admin,userSecretName=pvc-ceph-client-key
ReclaimPolicy:   Delete
Events:          <none>
admin@kubenode01:~$

The parameters are what we’re looking for here. If we see parameters passed to the StorageClass correctly, we will see the ceph-mon.ceph.svc.cluster.local:6789 hostname/port, things like userid, and appropriate secrets used for volume claims.