Extend the data volumes

Volume expansion is only available if the underlying StorageClass has the option allowVolumeExpansion set to true. See Expanding Persistent Volumes Claims for more information, including a list of volume types supported.

After StatefulSet objects are created, the only items that can be modified are the number of replicas, the update strategy, and the object template. Attempting to modify any other specifications returns this error:

# * spec: Forbidden: updates to statefulset spec for fields other than ‘replicas’, ‘template’, and ‘updateStrategy’ are forbidden.

Expand the volume without downtime

To expand the volume without downtime:

1. Delete the StatefulSet set without deleting the pods by entering this command:

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   kubectl delete sts <statefulset-name>--cascade=orphan -n <release-namespace>
   

   Note:

   This will cause orphan pods. However, there will not be any downtime.

2. Modify each PVC with the desired size by entering this command:

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   kubectl edit pvc <pvc-name> -n <release-namespace>
   

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   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     annotations:
   ...
     labels:
       app.kubernetes.io/instance: huge-ml
       app.kubernetes.io/name: marklogic
     name: datadir-huge-ml-marklogic-0
     namespace: ml
   spec:
     accessModes:
     - ReadWriteOnce
     resources:
       requests:
         storage: 80Gi (old size 20Gi)
     storageClassName: gp3
   

3. Recreate the StatefulSet with the new storage request. First, modify thevalues.yaml used to deploy the ML-cluster:

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   # Configure persistence using persistent Volume Claim
   # ref: https://kubernetes.io/docs/concepts/storage/persistent-volumes
     /#persistentvolumeclaims
   # The "" storageClass will use the default storage class for your cluster. 
     (gp2 for EKS, standard for Minikube)
   # If set the enabled to false, it will use EmptyDir
   volumepersistence:
     enabled: true
     storageClass: "gp3"
     size: 80Gi<---New size
     annotations: {}
     accessModes:
       - ReadWriteOnce
     mountPath: /var/opt/MarkLogic
   

4. Next, upgrade the Helm Chart by entering this command:

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   helm upgrade <release name> -n <release-namespace> marklogic --version <version> - f <path-to-values-file>