raynix 筆記

How to Mount an Existing Google Persistent Disk to a Pod in GKE

TL; DR: Below are steps to mount an existing Google Persistent Disk to a pod in a GKE cluster in the same region.

Most of the time I’d prefer to run stateless pods in Kubernetes clusters – they come, they go, as if nothing happened. When there are things to be persisted, a Persistent Volume will be handy. But what if I ran some app in a VM, with its data in a Persistent Disk, and now I want to migrate the app into GKE with its existing data? To my surprise, the solution is already there and up for grabs.

First, imagine the Persistent Disk is called my-pd-01, I can create a Persistent Volume resource as following, referring to the existing PD.

apiVersion: v1
kind: PersistentVolume
metadata:
  labels:
    name: my-pd-01
  name: my-pd-01
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 50Gi
  claimRef:
    name: my-pd-01
    namespace: my-namespace
  csi:
    driver: pd.csi.storage.gke.io
    # the format is projects/<project name>/zones/<zone of pd>/disks/<pd name>
    volumeHandle: projects/my-gcp-project-name/zones/australia-southeast1-c/disks/my-pd-01
  persistentVolumeReclaimPolicy: Retain
  storageClassName: ssd
  volumeMode: Filesystem

Then this PV can be claimed by the PVC mentioned above

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pd-01
  namespace: my-namespace
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 50Gi
  storageClassName: ssd
  volumeMode: Filesystem
  volumeName: my-pd-01

Finally the PVC can be mounted as a disk in a pod

...
spec:  
  containers:
    name: my-test
    image: ubuntu
    volumeMounts:
    - mountPath: /var/lib/test
      name: data-mount
...
  volumes:
  - name: data-mount
    persistentVolumeClaim:
      claimName: my-pd-01

🙂

admin

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