How to Migrate Ceph Monitors using PVCs to Host Path - OpenShift Data Foundation (ODF)

Issue

In some instances, usually, dynamic/datastore derived ODF deployments the Ceph Monitor (mons) resources are PVC backed. Although perfectly safe and fine, this causes an extra step in a migration process where the mons would need to be migrated to a new datastore/storageclass as opposed to the mons being backed by a host path that lives in /var/lib/rook on the storage nodes. Many believe the host path method to be more robust/safer as it takes the PVC aspect out of the equation. For example, if there is a problem with a datastore/storageclass (getting full). This process will show how to migrate the Ceph mons to host path.

NAME                         STATUS  VOLUME                                    CAPACITY  ACCESS MODES  STORAGECLASS                 AGE
rook-ceph-mon-a              Bound   local-pv-7e6f890b                         10Gi      RWO           localfile                    3d
rook-ceph-mon-b              Bound   local-pv-75cde50e                         10Gi      RWO           localfile                    3d
rook-ceph-mon-c              Bound   local-pv-49e39462                         10Gi      RWO           localfile                    3d

If this is not the desired solution, but instead wanting the reverse (migrating host path to PVC backed mons), please review the How to migrate OCS MON using hostpath to MON's using PVC, in an Red Hat OpenShift Container Storage 4.x cluster? solution.