Using OCI File Storage (FSS) for persistent volumes

If you are running your Kubernetes cluster on Oracle Container Engine for Kubernetes (commonly known as OKE), and you use OCI File Storage (FSS) for persistent volumes to store the WebLogic domain home, then the file system handling, as demonstrated in the operator persistent volume sample, will require an update to properly initialize the file ownership on the persistent volume when the domain is initially created.

File permission handling on persistent volumes can differ between cloud providers and even with the underlying storage handling on Linux based systems. These instructions provide one option to update file ownership used by the standard Oracle images where UID 1000 and GID 1000 typically represent the oracle or opc user. For more information on persistent volume handling, see Persistent storage.

Failure during domain creation with persistent volume sample

The existing sample for creation of a domain home on persistent volume uses a Kubernetes Job to create the domain. The sample uses an initContainers section to change the file ownership which will fail for OCI FSS created volumes used with an OKE cluster.

The OCI FSS volume contains some files that are not modifiable thus causing the Kubernetes Job to fail. The failure is seen in the description of the Kubernetes Job pod:

$ kubectl describe -n domain1-ns pod domain1-create-weblogic-sample-domain-job-wdkvs
   :
   :
Init Containers:
  fix-pvc-owner:
    Container ID:  docker://7051b6abdc296c76e937246df03d157926f2f7477e63b6af3bf65f6ae1ceddee
    Image:         container-registry.oracle.com/middleware/weblogic:12.2.1.3
    Image ID:      docker-pullable://container-registry.oracle.com/middleware/weblogic@sha256:47dfd4fdf6b56210a6c49021b57dc2a6f2b0d3b3cfcd253af7a75ff6e7421498
    Port:          <none>
    Host Port:     <none>
    Command:
      sh
      -c
      chown -R 1000:0 /shared
    State:          Terminated
      Reason:       Error
      Exit Code:    1
      Started:      Wed, 12 Feb 2020 18:28:53 +0000
      Finished:     Wed, 12 Feb 2020 18:28:53 +0000
    Ready:          False
    Restart Count:  0
    Environment:    <none>

   :

Updating the domain on persistent volume sample

In the following snippet of the create-domain-job-template.yaml, you can see the updated command for the init container:

apiVersion: batch/v1
kind: Job
metadata:
  name: %DOMAIN_UID%-create-weblogic-sample-domain-job
  namespace: %NAMESPACE%
spec:
  template:
    metadata:
  :
  :
    spec:
      restartPolicy: Never
      initContainers:
        - name: fix-pvc-owner
          image: %WEBLOGIC_IMAGE%
          command: ["sh", "-c", "chown 1000:0 %DOMAIN_ROOT_DIR%/. && find %DOMAIN_ROOT_DIR%/. -maxdepth 1 ! -name '.snapshot' ! -name '.' -print0 | xargs -r -0 chown -R 1000:0"]
          volumeMounts:
          - name: weblogic-sample-domain-storage-volume
            mountPath: %DOMAIN_ROOT_DIR%
          securityContext:
            runAsUser: 0
            runAsGroup: 0
      containers:
        - name: create-weblogic-sample-domain-job
          image: %WEBLOGIC_IMAGE%

  :

Use this new command in your copy of this template file. This will result in the ownership being updated for the expected files only, before the WebLogic domain is created on the persistent volume.