Debugging Kubernetes PVCs

 

While attempting to create a Tekton Pipeline consisting of multiple tasks recently, I was having a terrible time trying to work out what the various directory definitions were between tasks.  These are pre-defined tasks so not ones that I had written myself and hence it can be a bit tricky to try to pick your way through all the various bits of yaml involved.  What I really wanted to do (and what helped me debug the issue with my pipeline) was take a look at the content of the PVC (Persistent Volume Claim) that the pipeline was using.

 

Thanks to a really helpful post, it's quite simple to spin up a little pod that mounts your PVC. You can then exec a shell into the pod and take a look around your PVC. 

 

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: pvc-inspector
spec:
  containers:
  - image: busybox
    name: pvc-inspector
    command: ["tail"]
    args: ["-f", "/dev/null"]
    volumeMounts:
    - mountPath: /pvc
      name: pvc-mount
  volumes:
  - name: pvc-mount
    persistentVolumeClaim:
      claimName: pvc-name
EOF

 

The above will set up a pod that will stay running (thanks to the tail command) and mount your pvc "pvc-name" to /pvc, then all you need to do is start a shell

kubectl exec -it pvc-inspector -- sh

When you're done, you can exit and then delete the pod with

kubectl delete pod pvc-inspector