Chapter 3. Regional-DR solution for OpenShift Data Foundation

Procedure

1. Log in to the RHACM console using your OpenShift credentials if not already logged in.

   $ oc get route multicloud-console -n open-cluster-management -o jsonpath --template="https://{.spec.host}/multicloud/applications{'\n'}"

   Example Output:

   https://multicloud-console.apps.perf3.example.com/multicloud/applications

2. Navigate to Applications and click Create application.
3. Select type as Subscription.
4. Enter your application Name (for example, busybox) and Namespace (for example, busybox-sample).
5. In the Repository location for resources section, select Repository type Git.

6. Enter the Git repository URL for the sample application, the github Branch and Path where the resources busybox Pod and PVC will be created.

   Use the sample application repository as https://github.com/red-hat-storage/ocm-ramen-samples/tree/release-4.11 where the Branch is main and Path is busybox-odr.

7. Scroll down in the form until you see Deploy application resources only on clusters matching specified labels and then add a label with its value set to the Primary managed cluster name in RHACM cluster list view.

   

8. Click Create which is at the top right hand corner.

   On the follow-on screen go to the Topology tab. You should see that there are all Green checkmarks on the application topology.

   Note

   To get more information, click on any of the topology elements and a window will appear on the right of the topology view.

9. Validating the sample application deployment.

   Now that the busybox application has been deployed to your preferred Cluster, the deployment can be validated.

   Login to your managed cluster where busybox was deployed by RHACM.

   $ oc get pods,pvc -n busybox-sample

   Example output:

   NAME          READY   STATUS    RESTARTS   AGE
   pod/busybox   1/1     Running   0          6m
   
   NAME                                STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                  AGE
   persistentvolumeclaim/busybox-pvc   Bound    pvc-a56c138a-a1a9-4465-927f-af02afbbff37   5Gi        RWO            ocs-storagecluster-ceph-rbd   6m

1. On the Hub cluster go back to the Multicluster Web console, navigate to All Clusters.
2. Login to all the clusters listed under All Clusters.
3. Navigate to Data Services and then click Data policies.

4. Click the Actions menu at the end of DRPolicy to view the list of available actions.

   
5. Click Apply DRPolicy.

6. When the Apply DRPolicy modal is displayed, select busybox application and enter PVC label as appname=busybox.

   Note

   When multiple placements rules under the same application or more than one application are selected, all PVCs within the application’s namespace will be protected by default.

7. Click Apply.

8. Verify that a DRPlacementControl or DRPC was created in the busybox-sample namespace on the Hub cluster and that it’s CURRENTSTATE shows as Deployed. This resource is used for both failover and relocate actions for this application.

   $ oc get drpc -n busybox-sample

   Example output:

   NAME                       AGE     PREFERREDCLUSTER   FAILOVERCLUSTER   DESIREDSTATE   CURRENTSTATE
   busybox-placement-1-drpc   6m59s   ocp4bos1                                            Deployed

Procedure

1. On the RHACM console, navigate to Applications.
2. Search for the sample application to be deleted (for example, busybox).
3. Click the Action Menu (⋮) next to the application you want to delete.

4. Click Delete application.

   When the Delete application is selected a new screen will appear asking if the application related resources should also be deleted.

5. Select Remove application related resources checkbox to delete the Subscription and PlacementRule.
6. Click Delete. This will delete the busybox application on the Primary managed cluster (or whatever cluster the application was running on).

7. In addition to the resources deleted using the RHACM console, the DRPlacementControl must also be deleted after deleting the busybox application.

   1. Login to the OpenShift Web console for the Hub cluster and navigate to Installed Operators for the project busybox-sample.
   2. Click OpenShift DR Hub Operator and then click DRPlacementControl tab.
   3. Click the Action Menu (⋮) next to the busybox application DRPlacementControl that you want to delete.
   4. Click Delete DRPlacementControl.
   5. Click Delete.

Procedure

1. On the Hub cluster, navigate to Installed Operators and then click Openshift DR Hub Operator.

2. Click DRPlacementControl tab.

   Note

   Make sure to be in the busybox-sample namespace.

3. Click DRPC busybox-placement-1-drpc and then the YAML view.

4. Add the action and failoverCluster details as shown in the screenshot below.

   DRPlacementControl add action Failover

   

   The failoverCluster should be the RHACM cluster name for the Secondary managed cluster.

5. Click Save.

6. Verify that the CURRENTSTATE of DRPlacementControl or DRPC in the busybox-sample namespace on the Hub cluster is FailedOver.

   $ oc get drpc -n busybox-sample

   Example output:

   NAME                       AGE     PREFERREDCLUSTER   FAILOVERCLUSTER   DESIREDSTATE   CURRENTSTATE
   busybox-placement-1-drpc   6m59s   ocp4bos1           ocp4bos2          Failover       FailedOver

7. Verify that for the failover cluster ocp4bos2 as specified in the YAML file, the application busybox is now running in the Secondary managed cluster.

   $ oc get pods,pvc -n busybox-sample

   Example output:

   NAME          READY   STATUS    RESTARTS   AGE
   pod/busybox   1/1     Running   0          35s
   
   NAME                                STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                  AGE
   persistentvolumeclaim/busybox-pvc   Bound    pvc-79f2a74d-6e2c-48fb-9ed9-666b74cfa1bb   5Gi        RWO            ocs-storagecluster-ceph-rbd   35s

8. Verify if busybox is running in the Primary managed cluster. The busybox application should no longer be running on this managed cluster.

   $ oc get pods,pvc -n busybox-sample

   Example output:

   No resources found in busybox-sample namespace.

9. Verify if the DNS routes for the application are configured correctly. If the external routes are not configured, you can use either Global Traffic Manager (GTM) or Global Server Load Balancing (GLSB) service to reconfigure the routes.

Procedure

1. On the Hub cluster, navigate to Installed Operators and then click Openshift DR Hub Operator.
2. Click DRPlacementControl tab.
3. Click DRPC busybox-placement-1-drpc and then the YAML view.

4. Modify action to Relocate.

   DRPlacementControl modify action to Relocate

   

5. Click Save.

6. Verify that the CURRENTSTATE of DRPlacementControl or DRPC in the busybox-sample namespace on the Hub cluster is Relocated.

   $ oc get drpc -n busybox-sample

   Example output:

   NAME                       AGE     PREFERREDCLUSTER   FAILOVERCLUSTER   DESIREDSTATE   CURRENTSTATE
   busybox-placement-1-drpc   6m59s   ocp4bos1           ocp4bos2          Relocate       Relocated

7. Verify if the application busybox is now running in the Primary managed cluster. The relocate is to the preferredCluster ocp4bos1 as specified in the YAML file, which is where the application was running before the failover operation.

   $ oc get pods,pvc -n busybox-sample

   Example output:

   NAME          READY   STATUS    RESTARTS   AGE
   pod/busybox   1/1     Running   0          60s
   
   NAME                                STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                  AGE
   persistentvolumeclaim/busybox-pvc   Bound    pvc-79f2a74d-6e2c-48fb-9ed9-666b74cfa1bb   5Gi        RWO            ocs-storagecluster-ceph-rbd   61s

8. Verify if busybox is running in the Secondary managed cluster. The busybox application should no longer be running on this managed cluster.

   $ oc get pods,pvc -n busybox-sample

   Example output:

   No resources found in busybox-sample namespace.

9. Verify if the DNS routes for the application are configured correctly. If the external routes are not configured, you can use either Global Traffic Manager (GTM) or Global Server Load Balancing (GLSB) service to reconfigure the routes.