Similarly to block volume replication, Ceph is capable of replicating the
content of a Ceph Filesystem from one cluster to another.
For this, during the 1.6 cycle, we introduced a new CRD called
CephFilesystemMirror which effectively deploys a cephfs-mirror daemon.
However, configuring peers to enable replication between two clusters
had to be done manually.
Also various bug fix made it in Ceph eventually and the minimum required
version for this to work is to run on Ceph Pacific 16.2.5 at least.
So the automatic configuration of Ceph Filesystem peers is now possible.
By editing the CephFilesystem CRD, you can now turn on mirroring:
```yaml
mirroring:
enabled: false
# list of Kubernetes Secrets containing the peer token
# for more details see: https://docs.ceph.com/en/latest/dev/cephfs-mirroring/#bootstrap-peers
peers:
secretNames:
- secondary-cluster-peer
```
Also, the mirroring status is displayed in the CR status:
```
status:
info:
fsMirrorBootstrapPeerSecretName: fs-peer-token-myfs
mirroringStatus:
daemonsStatus:
- daemon_id: 4186
filesystems:
- filesystem_id: 2
name: myfs
lastChecked: "2021-07-01T14:16:29Z"
phase: Ready
snapshotScheduleStatus:
lastChecked: "2021-07-01T14:16:29Z"
snapshotSchedules:
- fs: myfs
path: /
rel_path: /
retention: {}
schedule: 24h
```
Closes: https://github.com/rook/rook/issues/7063
Signed-off-by: Sébastien Han <seb@redhat.com>
