Increase Replica With Volume of Arbitrary Size With K8s Stateful Set

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Introduction

Once Statefulset is deployed, volumeClaimTemplates etc. cannot be changed. However, there is a way to change the Volume.

As a result, the volume size in volumeClaimTemplates on the code and the size actually used are different. In that state, if you try to Scale, the volume and size that have already been expanded will be different, and the balance will be lost.

Solution

• Create PVC according to the naming convention of pvc generated by Volume size + statefulset
• Scale out

Create PVC

The pvc created from VolumeClaimTemplate is, <volumeClaimTemplateName>-<pod_name>so in this case it was test-storage-4-testing.

...
  volumeClaimTemplates:
  - metadata:
      name: test-storage
      annotations:
        volume.beta.kubernetes.io/storage-class: gp2-topology-aware
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 10Gi

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    volume.beta.kubernetes.io/storage-class: gp2-topology-aware
  name: test-storage-4-testing
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 3Gi

At this time, if volumeBindingMode: WaitForFirstConsumer you are using it, wait until the pod claims and the following message appears

Normal WaitForFirstConsumer 11s (x3 over 20s) persistentvolume-controller waiting for first consumer to be created before binding