3.10. Configure DRClusters for fencing automation
This configuration is required for enabling fencing prior to application failover. In order to prevent writes to the persistent volume from the cluster which is hit by a disaster, OpenShift DR instructs Red Hat Ceph Storage (RHCS) to fence the nodes of the cluster from the RHCS external storage. This section guides you on how to add the IPs or the IP Ranges for the nodes of the DRCluster.
3.10.1. Add node IP addresses to DRClusters
Find the IP addresses for all of the OpenShift nodes in the managed clusters by running this command in the Primary managed cluster and the Secondary managed cluster.
$ oc get nodes -o jsonpath='{range .items[*]}{.status.addresses[?(@.type=="ExternalIP")].address}{"\n"}{end}'Example output:
10.70.56.118 10.70.56.193 10.70.56.154 10.70.56.242 10.70.56.136 10.70.56.99Once you have the
IP addressesthen theDRClusterresources can be modified for each managed cluster.Find the DRCluster names on the Hub Cluster.
$ oc get drclusterExample output:
NAME AGE ocp4perf1 5m35s ocp4perf2 5m35sEdit each DRCluster to add your unique IP addresses after replacing
<drcluster_name>with your unique name.$ oc edit drcluster <drcluster_name>apiVersion: ramendr.openshift.io/v1alpha1 kind: DRCluster metadata: [...] spec: s3ProfileName: s3profile-<drcluster_name>-ocs-external-storagecluster ## Add this section cidrs: - <IP_Address1>/32 - <IP_Address2>/32 - <IP_Address3>/32 - <IP_Address4>/32 - <IP_Address5>/32 - <IP_Address6>/32 [...]Example output:
drcluster.ramendr.openshift.io/ocp4perf1 edited
There could be more than six IP addresses.
Modify this DRCluster configuration also for IP addresses on the Secondary managed clusters in the peer DRCluster resource (e.g., ocp4perf2).
3.10.2. Add fencing annotations to DRClusters
Add the following annotations to all the DRCluster resources. These annotations include details needed for the NetworkFence resource created later in these instructions (prior to testing application failover).
Replace <drcluster_name> with your unique name.
$ oc edit drcluster <drcluster_name>apiVersion: ramendr.openshift.io/v1alpha1
kind: DRCluster
metadata:
## Add this section
annotations:
drcluster.ramendr.openshift.io/storage-clusterid: openshift-storage
drcluster.ramendr.openshift.io/storage-driver: openshift-storage.rbd.csi.ceph.com
drcluster.ramendr.openshift.io/storage-secret-name: rook-csi-rbd-provisioner
drcluster.ramendr.openshift.io/storage-secret-namespace: openshift-storage
[...]Example output:
drcluster.ramendr.openshift.io/ocp4perf1 edited
Make sure to add these annotations for both DRCluster resources (for example: ocp4perf1 and ocp4perf2).
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