Increase Storage for Persistent Volumes

Create or identify a persistent custom resource.

Use an existing database resource or create a new one with persistent storage. Wait until the persistent volume enters the Running state.

1
apiVersion: mongodb.com/v1
2
kind: MongoDB
3
metadata:
4
  name: <my-replica-set>
5
spec:
6
  members: 3
7
  version: "4.4.0"
8
  project: my-project
9
  credentials: my-credentials
10
  type: ReplicaSet
11
  podSpec:
12
    persistence:
13
      single:
14
        storage: "1Gi"

Insert data into the database that the resource serves.

1. Start mongo in the Kubernetes cluster.

   $kubectl exec -it <my-replica-set>-0 \
            /var/lib/mongodb-mms-automation/mongodb-linux-x86_64-4.4.0/bin/mongo

2. Insert data into the test database.

   <my-replica-set>:PRIMARY> use test
   switched to db test
   <my-replica-set>:PRIMARY> db.tmp.insertOne({"foo":"bar"})
   {
     "acknowledged" : true,
     "insertedId" : ObjectId("61128cb4a783c3c57ae5142d")
   }

Update the database resource with a new storage value.

1. Update the disk size. Open your preferred text editor and make changes similar to this example:

   Example

   To update the disk size of the replica set to 2 GB, change the storage value in the database resource specification:

   1
   apiVersion: mongodb.com/v1
   2
   kind: MongoDB
   3
   metadata:
   4
     name: <my-replica-set>
   5
   spec:
   6
     members: 3
   7
     version: "4.4.0"
   8
     project: my-project
   9
     credentials: my-credentials
   10
     type: ReplicaSet
   11
     podSpec:
   12
       persistence:
   13
         single:
   14
           storage: "2Gi"

2. Update the MongoDB custom resource with the new volume size.

   kubectl apply -f my-updated-replica-set-vol.yaml

3. Wait until this StatefulSet achieves the Running state.

Validate that the Persistent Volume Claim has been resized.

If you reuse Persistent Volumes, you can find the data that you inserted in Step 2 on the databases stored in Persistent Volumes:

$ kubectl describe mongodb/<my-replica-set> -n mongodb

The following output indicates that your PVC resize request is being processed.

status:
  clusterStatusList: {}
  lastTransition: "2024-08-21T11:03:52+02:00"
  message: StatefulSet not ready
  observedGeneration: 2
  phase: Pending
  pvc:
    - phase: PVC Resize - STS has been orphaned
      statefulsetName: multi-replica-set-pvc-resize-0
  resourcesNotReady:
    - kind: StatefulSet
      message: 'Not all the Pods are ready (wanted: 2, updated: 1, ready: 1, current:2)'
      name: multi-replica-set-pvc-resize-0
  version: ""

Validate data exists on the updated Persistent Volume Claim.

If you reuse Persistent Volumes, you can find the data that you inserted in Step 2 on the databases stored in Persistent Volumes:

$ kubectl exec -it <my-replica-set>-1 \
          /var/lib/mongodb-mms-automation/mongodb-linux-x86_64-4.4.0/bin/mongo

<my-replica-set>:PRIMARY> use test
switched to db test
<my-replica-set>:PRIMARY> db.tmp.count()
1

Create or identify a persistent custom resource.

Use an existing database resource or create a new one with persistent storage. Wait until the persistent volume gets to the Running state.

1
apiVersion: mongodb.com/v1
2
kind: MongoDB
3
metadata:
4
  name: <my-replica-set>
5
spec:
6
  members: 3
7
  version: "4.4.0"
8
  project: my-project
9
  credentials: my-credentials
10
  type: ReplicaSet
11
  podSpec:
12
    persistence:
13
      single:
14
        storage: "1Gi"

Insert data to the database that the resource serves.

1. Start mongo in the Kubernetes cluster.

   $kubectl exec -it <my-replica-set>-0 \
            /var/lib/mongodb-mms-automation/mongodb-linux-x86_64-4.4.0/bin/mongo

2. Insert data into the test database.

   <my-replica-set>:PRIMARY> use test
   switched to db test
   <my-replica-set>:PRIMARY> db.tmp.insertOne({"foo":"bar"})
   {
     "acknowledged" : true,
     "insertedId" : ObjectId("61128cb4a783c3c57ae5142d")
   }

Patch each persistence volume.

Invoke the following commands for the entire replica set:

kubectl patch pvc/"data-<my-replica-set>-0" -p='{"spec": {"resources": {"requests": {"storage": "2Gi"}}}}'
kubectl patch pvc/"data-<my-replica-set>-1" -p='{"spec": {"resources": {"requests": {"storage": "2Gi"}}}}'
kubectl patch pvc/"data-<my-replica-set>-2" -p='{"spec": {"resources": {"requests": {"storage": "2Gi"}}}}'

Wait until each Persistent Volume Claim gets to the following condition:

- lastProbeTime: null
  lastTransitionTime: "2019-08-01T12:11:39Z"
  message: Waiting for user to (re-)start a pod to finish file
           system resize of volume on node.
  status: "True"
  type: FileSystemResizePending

Stop the Operator.

Update the Kubernetes Operator deployment definition and apply the change to your Kubernetes cluster in order to scale the Kubernetes Operator down to 0 replicas. Scaling the Kubernetes Operator down to 0 replicas allows you to avoid a race condition in which the Kubernetes Operator tries to restore the state of the manually updated resource to align with the resource's original definition.

# Source: enterprise-operator/templates/operator.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongodb-enterprise-operator
  namespace: mongodb
spec:
  replicas: 0

Remove the StatefulSets.

Delete a StatefulSet resource.

kubectl delete sts --cascade=false <my-replica-set>

Update the database resource with a new storage value.

1. Update the disk size. Open your preferred text editor and make changes similar to this example:

   Example

   To update the disk size of the replica set to 2 GB, change the storage value in the database resource specification:

   1
   apiVersion: mongodb.com/v1
   2
   kind: MongoDB
   3
   metadata:
   4
     name: <my-replica-set>
   5
   spec:
   6
     members: 3
   7
     version: "4.4.0"
   8
     project: my-project
   9
     credentials: my-credentials
   10
     type: ReplicaSet
   11
     podSpec:
   12
       persistence:
   13
         single:
   14
           storage: "2Gi"

2. Recreate a StatefulSet resource with the new volume size.

   kubectl apply -f my-replica-set-vol.yaml

3. Wait until the MongoDB custom resource is in a Running state.

Update the pods in a rolling fashion.

Invoke the following command:

kubectl rollout restart sts <my-replica-set>

The new pods mount the resized volume.

Validate data exists on the updated Persistent Volume Claim.

If the Persistent Volumes were reused, the data that you inserted in Step 2 can be found on the databases stored in Persistent Volumes:

$ kubectl exec -it <my-replica-set>-1 \
          /var/lib/mongodb-mms-automation/mongodb-linux-x86_64-4.4.0/bin/mongo

<my-replica-set>:PRIMARY> use test
switched to db test
<my-replica-set>:PRIMARY> db.tmp.count()
1