Migrate to FileStorage (RWX) for Imaging Kubernetes deployments

Overview

This guide describes how to convert the pvc-shared-datadir PVC used by the analysis-node from DiskStorage (ReadWriteOnce/RWO) to FileStorage (ReadWriteMany/RWX) on an existing CAST Imaging deployment on Kubernetes. This conversion is required as part of updating to CAST Imaging 3.6.x-funcrel when your deployment currently uses AnalysisNodeFS.enable=false.

Once complete, continue with the standard Cloud services via Kubernetes update process.

Applicability

This procedure applies only if all of the following are true:

• You are upgdating from CAST Imaging < 3.6.0-funcrel to 3.6.0-funcrel or later
• You currently run a single analysis-node (multiple analysis nodes already use FileStorage - this procedure is not needed)
• Your current deployment uses AnalysisNodeFS.enable=false

It applies whether or not you plan to use multiple analysis nodes in the future.

Important note

During this procedure, the analysis-node will be shut down and no analyses will be able to run. imaging-services, dashboards, and imaging-viewer will remain available throughout.

Prerequisites

• A local machine with the kubectl tool installed and remote access to the Kubernetes cluster running your CAST Imaging instance
• The examples below assume the namespace is castimaging-v3 - replace this with your actual namespace value

Conversion procedure

Step 1 - Prepare the migration

Run helm upgrade with the following values:

prepareMigrationToAnalysisNodeFS: true
AnalysisNodeReplicaCount: 0
AnalysisNodeFS:
  enable: false

This will:

• Scale down the analysis-node
• Create a new pvc-shared-datadir-mig volume (FileStorage)
• Run a job to copy the current volume content to pvc-shared-datadir-mig

Step 2 - Verify the copy job succeeded

Check the status of the save-pvc-data-xxxxx pod - it should show Completed. To find its name:

kubectl get pods -n castimaging-v3

To view the log:

kubectl logs save-pvc-data-xxxxx -n castimaging-v3

If the job failed, follow these recovery steps:

a) Examine the pod status, log file, and cluster events to identify and fix the issue. One possible cause is a File Storage provisioning problem - check cluster events and provisioner logs.

b) Once the issue is resolved, delete the failed job, the migration PVC, and the storage class:

kubectl delete job save-pvc-data -n castimaging-v3
kubectl delete pvc pvc-shared-datadir-mig -n castimaging-v3
kubectl delete sc castimaging-fs

c) Re-run helm upgrade with the same values as Step 1 and repeat from step a) above until the job completes successfully.

Step 3 - Delete the old PVC

Once the job has succeeded, delete the job and the old PVC:

kubectl delete job save-pvc-data -n castimaging-v3
kubectl delete pvc pvc-shared-datadir -n castimaging-v3

Step 4 - Restart the analysis-node

Run helm upgrade with the following values:

prepareMigrationToAnalysisNodeFS: true
AnalysisNodeReplicaCount: 1
AnalysisNodeFS:
  enable: true

This will restart the analysis-node using the new FileStorage PVC and copy the saved data from pvc-shared-datadir-mig to pvc-shared-datadir via an init-container.

Step 5 - Global health check

Check pod statuses, open CAST Imaging, and confirm all services are up.

Step 6 - Cleanup

Run helm upgrade with the following values:

prepareMigrationToAnalysisNodeFS: false
AnalysisNodeReplicaCount: 1
AnalysisNodeFS:
  enable: true

This will delete the pvc-shared-datadir-mig PVC and perform a final restart of the analysis-node.

The FileStorage migration is now complete. Continue with the standard Cloud services via Kubernetes update process to finish updating to the new release.