How to delete a persistent volume claim using a resource template?

[plopezgarcia]

Hi, I came across this problem: #3657 which is basically that the standard garbage collection doesn't work for persistent volume claims created at template level, so they remain there even when the workflow pod that instantiated the template has finished and has been removed using the podGC directive.

The OP claimed to have a solution Found a way to do it by creating a new resource template to delete the PVCs. but the code was never posted there and after a lot of tried failures here I am asking for help. In the issue above are my attempts. Can anyone please give a hand? Essentially I would just need the equivalent of this an argo template: "kubectl delete pvc pvc-my-volume -n argo" (works perfectly from the command line) but I can't seem to figure it out. I thought this would work but doesn't:

     - name: delete-volume
        inputs:
          parameters:
            - name: pvc-name
        resource:
          action: delete
          setOwnerReference: true
          manifest: |
            apiVersion: v1
            kind: PersistentVolumeClaim
            metadata:
              namespace: "argo"
              name: "'{{inputs.parameters.pvc-name}}'"`

Thanks a lot in advance!

[wesleyscholl]

@plopezgarcia

This is a basic functional workflow that uses the resource template to create a PersistentVolumeClaim, delete the PersistentVolumeClaim, and validate deletion.

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: pvc-resource-deletion-example-
  namespace: argo
spec:
  templates:
    - name: pvc-lifecycle
      inputs: {}
      outputs: {}
      metadata: {}
      dag:
        tasks:
          - name: create-pvc
            template: create-pvc
            arguments: {}
          - name: delete-pvc
            template: delete-pvc
            arguments:
              parameters:
                - name: pvc-name
                  value: pvc-test
            dependencies:
              - create-pvc
          - name: validate-pvc-deletion
            template: validate-pvc-deletion
            arguments:
              parameters:
                - name: pvc-name
                  value: pvc-test
            dependencies:
              - delete-pvc
    - name: create-pvc
      inputs: {}
      outputs: {}
      metadata: {}
      resource:
        action: create
        manifest: |
          apiVersion: v1
          kind: PersistentVolumeClaim
          metadata:
            name: pvc-test
            namespace: argo
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 1Gi
    - name: delete-pvc
      inputs:
        parameters:
          - name: pvc-name
      outputs: {}
      metadata: {}
      resource:
        action: delete
        manifest: |
          apiVersion: v1
          kind: PersistentVolumeClaim
          metadata:
            name: "{{inputs.parameters.pvc-name}}"
            namespace: "argo"
    - name: validate-pvc-deletion
      inputs:
        parameters:
          - name: pvc-name
      outputs: {}
      metadata: {}
      script:
        name: ""
        image: alpine:latest
        command:
          - sh
          - "-c"
        resources: {}
        source: >
          if kubectl get pvc "{{inputs.parameters.pvc-name}}" -n argo >
          /dev/null 2>&1; then
            echo "PVC '{{inputs.parameters.pvc-name}}' still exists."
            exit 1
          else
            echo "PVC '{{inputs.parameters.pvc-name}}' has been successfully deleted."
            exit 0 
          fi
  entrypoint: pvc-lifecycle
  arguments: {}

Resources

• https://argo-workflows.readthedocs.io/en/latest/walk-through/kubernetes-resources/
• https://github.com/argoproj/argo-workflows/blob/main/docs/workflow-concepts.md#resource
• https://argo-workflows.readthedocs.io/en/latest/walk-through/volumes/
• https://github.com/argoproj/argo-workflows/blob/main/examples/volumes-pvc.yaml
• https://argo-workflows.readthedocs.io/en/latest/fields/#persistentvolumeclaim