DRClusterConfig CRD

DRClusterConfig CRD

Overview

The DRClusterConfig custom resource provides cluster-specific disaster recovery configuration on managed clusters. It is a cluster-scoped resource that exists on each managed cluster (not on the hub) and serves two primary purposes:

  1. Configuration Communication: Conveys the cluster identity and desired replication schedules from the hub to the managed cluster
  2. Capability Discovery: Scans the cluster for storage-related classes (StorageClass, VolumeSnapshotClass, VolumeReplicationClass, etc.) that have the required Ramen labels/annotations and reports them in its status. See the Status Fields section below for the specific label/annotation requirements for each class type.

Note: DRClusterConfig does not create these classes. Storage providers or administrators must create and label/annotate the classes appropriately. DRClusterConfig only discovers and reports them in its status.

Lifecycle: Automatically created and managed by Ramen on each managed cluster. Users typically don’t create this resource manually.

Resource Name: The DRClusterConfig resource name matches the name of the managed cluster. For example, if the managed cluster is named “cluster1”, the DRClusterConfig resource will also be named “cluster1”.

API Group and Version

  • API Group: ramendr.openshift.io
  • API Version: v1alpha1
  • Kind: DRClusterConfig
  • Scope: Cluster (on managed clusters)

Spec Fields

Required Fields

clusterID (string)

The unique identifier for this cluster, derived from the kube-system namespace UID.

Source: OCM ManagedCluster claim value for id.k8s.io

Requirements:

  • Required field
  • Immutable after creation
  • Must be globally unique

Example:

clusterID: "a1b2c3d4-e5f6-7890-abcd-ef1234567890"

Purpose: Used to correlate storage resources across clusters and identify the cluster in S3 metadata.

Optional Fields

replicationSchedules ([]string)

List of desired replication schedules that storage providers should support.

Format: <num><m,h,d> where:

  • m = minutes
  • h = hours
  • d = days

Example:

replicationSchedules:
  - "5m"

Status Fields

The DRClusterConfig status is populated by the Ramen DR cluster operator, which scans the cluster for classes with the required labels/annotations and updates the status accordingly.

conditions ([]metav1.Condition)

Standard Kubernetes conditions array.

Condition type:

  • Processed - Indicates whether the DRClusterConfig configuration has been processed

Condition reasons:

  • "Initializing" - Condition is being initialized
  • "Succeeded" - Configuration processed successfully
  • "Failed" - Configuration processing failed

storageClasses ([]string)

List of StorageClass names that have the ramendr.openshift.io/storageid label.

Example:

storageClasses:
  - block-storage
  - file-storage

Purpose: Reports available storage classes to the hub for peer class discovery.

volumeSnapshotClasses ([]string)

List of VolumeSnapshotClass names with the ramendr.openshift.io/storageid label.

Example:

volumeSnapshotClasses:
  - csi-fileplugin-snapclass
  - csi-blockplugin-snapclass

Purpose: Used for sync DR (Metro DR) peer class matching.

volumeGroupSnapshotClasses ([]string)

List of VolumeGroupSnapshotClass names with the ramendr.openshift.io/storageid label.

Example:

volumeGroupSnapshotClasses:
  - csi-vg-snapclass

Purpose: Enables crash-consistent snapshots across multiple PVCs.

volumeReplicationClasses ([]string)

List of VolumeReplicationClass names with the ramendr.openshift.io/replicationid label.

Example:

volumeReplicationClasses:
  - block-replication-1h
  - block-replication-5m

Purpose: Used for async DR (Regional DR) peer class matching.

volumeGroupReplicationClasses ([]string)

List of VolumeGroupReplicationClass names with the ramendr.openshift.io/groupreplicationid label.

Example:

volumeGroupReplicationClasses:
  - block-group-replication

Purpose: Enables consistency group replication for multiple PVCs.

networkFenceClasses ([]string)

List of NetworkFenceClass names with the ramendr.openshift.io/storageid annotation.

Example:

networkFenceClasses:
  - network-fence-class

Purpose: Used by Metro DR for network-based cluster fencing.

Examples

DRClusterConfig with All Class Types

DRClusterConfig on a managed cluster with full storage capabilities:

apiVersion: ramendr.openshift.io/v1alpha1
kind: DRClusterConfig
metadata:
  name: cluster1
spec:
  clusterID: "b2c3d4e5-f6a7-8901-bcde-f12345678901"
  replicationSchedules:
    - "5m"
status:
  conditions:
    - type: Processed
      status: "True"
      reason: "Succeeded"
      message: "Configuration processed and validated"
      observedGeneration: 1
      lastTransitionTime: "2024-01-15T10:00:00Z"
  storageClasses:
    - block-storage
    - file-storage
  volumeSnapshotClasses:
    - csi-blockplugin-snapclass
    - csi-fileplugin-snapclass
  volumeGroupSnapshotClasses:
    - csi-vg-snapclass
  volumeReplicationClasses:
    - block-replication-5m
    - block-replication-30m
    - block-replication-1h
  volumeGroupReplicationClasses:
    - block-group-replication
  networkFenceClasses:
    - network-fence-class

Monitoring

Check Configuration Status

kubectl get drclusterconfig cluster1 -o yaml

Verify Processing

# Check Processed condition
kubectl get drclusterconfig cluster1 -o jsonpath='{.status.conditions[?(@.type=="Processed")].status}'

Monitor Class Discovery

# Watch for new classes being discovered
kubectl get drclusterconfig cluster1 -o jsonpath='{.status}' | jq

Troubleshooting

No Classes Discovered

Symptom: Status shows empty arrays for all class types.

Check:

  1. Verify classes exist in the cluster:

    # Check all class types
kubectl get storageclass
kubectl get volumesnapshotclass
kubectl get volumegroupsnapshotclass
kubectl get volumereplicationclass
kubectl get volumegroupreplicationclass
kubectl get networkfenceclass

  2. Verify classes have required labels/annotations:

    # Check for required labels/annotations on all class types
kubectl get storageclass -o yaml | grep "ramendr.openshift.io"
kubectl get volumesnapshotclass -o yaml | grep "ramendr.openshift.io"
kubectl get volumegroupsnapshotclass -o yaml | grep "ramendr.openshift.io"
kubectl get volumereplicationclass -o yaml | grep "ramendr.openshift.io"
kubectl get volumegroupreplicationclass -o yaml | grep "ramendr.openshift.io"
kubectl get networkfenceclass -o yaml | grep "ramendr.openshift.io"

  3. Verify Ramen DR cluster operator is running:

    kubectl get pods -n ramen-system

  4. Check Ramen DR cluster operator logs:

    kubectl logs -n ramen-system <pod-name> | grep -i "drclusterconfig"

Solution: Ensure classes exist in the cluster and have the required labels/annotations as specified in the Overview section. Classes without the required labels/annotations will not be discovered by DRClusterConfig.