Enabling Consistency Groups for CephFS Workloads - Developer preview OpenShift Data Foundation 4.17

Updated 5 Nov 2024

Enabling Consistency Groups per DRPlacementControl (DRPC)
When Disaster Recovery (DR) is enabled, each workload is one DRPC resource on the Hub cluster. To enable consistency groups for the workload, you must add an annotation to the DRPC resource to activate the consistency group feature. Add the following annotation to the DRPC resource.

drplacementcontrol.ramendr.openshift.io/is-cg-enabled: "true"

Example:

apiVersion: ramendr.openshift.io/v1alpha1
kind: DRPlacementControl
metadata:
  annotations:
    drplacementcontrol.ramendr.openshift.io/app-namespace: deployment-cephfs
    drplacementcontrol.ramendr.openshift.io/is-cg-enabled: "true"

This annotation is then propagated to the VolumeGroupReplication (VRG) on the Primary ManagedCluster. The VRG on the ManagedCluster uses this annotation to enable or disable the consistency group functionality.

ReplicationGroupSource
The ReplicationGroupSource is found on the Primary cluster for the workload and it functions similarly to volsync ReplicationSource, managing Volume Groups as a source. The following output displays two ReplicationGroupSources within the same namespace. For more details, refer to the design document: Content from github.com is not included.CephFS RDR Consistency Group.

oc get replicationgroupsource -A                                                                                     
NAMESPACE           NAME                      LAST SYNC              DURATION         NEXT SYNC              SOURCE                                                                     LAST SYNC START
deployment-cephfs   benamar-drpccg-for-lab1   2024-10-15T12:15:25Z   25.73188668s     2024-10-15T12:20:00Z   {"matchLabels":{"ramendr.openshift.io/consistency-group":"cg-for-lab1"}}   
deployment-cephfs   benamar-drpccg-for-lab2   2024-10-15T11:41:05Z   1m5.592738976s   2024-10-15T11:45:00Z   {"matchLabels":{"ramendr.openshift.io/consistency-group":"cg-for-lab2"}}   2024-10-15T11:45:03Z

Each ReplicationGroupSource manages the group's ReplicationSources.

oc get replicationsource -A
NAMESPACE           NAME               SOURCE                      
deployment-cephfs   busybox-cg1-pvc1   cephfscg-busybox-cg1-pvc1                                          
deployment-cephfs   busybox-cg1-pvc2   cephfscg-busybox-cg1-pvc2                                          
deployment-cephfs   busybox-cg2-pvc1   cephfscg-busybox-cg2-pvc1                                          
deployment-cephfs   busybox-cg2-pvc2   cephfscg-busybox-cg2-pvc2

ReplicationGroupDestination
The ReplicationGroupDestination is found on the Secondary cluster for the workload and it functions similarly to VolSync ReplicationDestination, managing Volume Groups as a destination. The following output displays two ReplicationGroupDestinations within the same namespace. For more details, refer to the design document: Content from github.com is not included.CephFS RDR Consistency Group.

oc get replicationgroupdestination -A
NAMESPACE           NAME                      LAST SYNC              DURATION         LAST SYNC START
deployment-cephfs   benamar-drpccg-for-lab1   2024-10-11T15:40:32Z   1m2.442756481s   2024-10-11T15:40:32Z
deployment-cephfs   benamar-drpccg-for-lab2   2024-10-11T15:40:10Z   1m10.88662613s   2024-10-11T15:40:10Z

Each ReplicationGroupDestination manages the group's ReplicationDestinations.

oc get replicationdestination -A
NAMESPACE           NAME               LAST SYNC              DURATION     
deployment-cephfs   busybox-cg1-pvc1   2024-10-11T15:40:29Z   59.095958069s     
deployment-cephfs   busybox-cg1-pvc2   2024-10-11T15:40:30Z   1m0.027646131s    
deployment-cephfs   busybox-cg2-pvc1   2024-10-11T15:40:09Z   1m8.00190091s     
deployment-cephfs   busybox-cg2-pvc2   2024-10-11T15:40:09Z   1m8.099932974s

In summary, this article provides guidance for enabling consistency groups in CephFS workloads through DRPlacementControl and VolumeGroupReplication. The outlined procedures ensure that consistency groups are effectively enabled to protect workloads across clusters.

Article Type

General