Disaster Recovery (DR)

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In your install configuration, if you have set persistence.enabled value to false, your data is stored only in the container and will be lost if the container restarts.

Note: It is best to back up your data regularly. For more information, see Backing up the CouchDB, in particular the

Recovery Point
Objective

section. Keep in mind, to recover your installation, you need to back up the configuration as well.

Note: In this section, we assume your data is not completely lost and can be accessed by providing a path to it.

Backup

Data

For instructions on how to back up your data, see Backing up the CouchDB. If you used existingClaim in your install, then PVs and PVCs need to be copied over into the new cluster before standing up a new Application Modernization Accelerator instance. You can use the following code to create YAML files for PV and PVCs. Apply them in the new cluster to create the objects.

oc -n <TA_NAME_SPACE> get pvc -o json | jq -Mr '.items[].spec.volumeName' | xargs -I {} -n 1 oc get pv {} -o json | jq -Mrc 'del(.status, .metadata.creationTimestamp, .metadata.uid, .metadata.resourceVersion, .metadata.finalizers, .metadata.annotations, .spec.claimRef)' >> pv.yaml

oc -n <TA_NAME_SPACE> get pvc -o json | jq -Mrc '.items[] | del(.status, .metadata.annotations, .metadata.creationTimestamp, .metadata.finalizers, .metadata.ownerReferences, .metadata.resourceVersion, .metadata.uid)' >> pvc.yaml

Application Modernization Accelerator config

Keep the original configs so that you can look them up while standing up a new Application Modernization Accelerator instance.

oc get transadvs.ta.ibm.com/ta -o yaml -n ta >> ta_instance_config.yaml

There is a good chance you will not be able to apply this YAML in the new cluster — some of the configs might change as they are cluster specific. It is best to create a new instance of Application Modernization Accelerator in the OCP UI (Create TransAdv page) and open the YAML view. Many of the configs will be populated by the pre-install process, and you can adjust them using common sense and by reviewing the original instance’s configuration.

Use existing data

OCP install

If running on OCP, you can install a new Application Modernization Accelerator instance pointing to the PVC you created earlier. This is the configuration section where this can be set.

  persistence:
    couchdb:
      supplementalGroups: []
      accessMode: ReadWriteOnce
      size: 20Gi
      useDynamicProvisioning: true
      existingClaim: '<PVC_NAME>'
      storageClassName: ''
    neo4j:
      supplementalGroups: []
      accessMode: ReadWriteOnce
      size: 5Gi
      useDynamicProvisioning: true
      existingClaim: '<PVC_NAME>'
      storageClassName: ''
    enabled: true

Make sure you preserve the accessMode and size values that you had before, in case you modified them.

Application Modernization Accelerator Local

Provided the data remains on the machine, follow instructions from Backing up the CouchDB in its Restoring data directories section.

Cluster configuration required

Application Modernization Accelerator has no special requirements on the cluster configuration except storage (see Configure Storage). Once Application Modernization Accelerator config and data are backed up, you can use them in the new installation.

Note: There is a limitation on the egress network policy — it is not enabled if the OCP is not using the OpenShift SDN default Container Network Interface (CNI) network provider.

Example config for a Application Modernization Accelerator instance

Application Modernization Accelerator provides two YAML files for Production and Quick Start configuration. They are available in the Create TransAdv page, YAML view, Samples tab.

External services required to be available

None