failed to create snapshot in k8s 1.20

[aboje]

We recently upgraded to k8s 1.20. I am having troubles creating volumesnapshots. Here is the error:

spec:
snapshotClassName: pure-snapshotclass
snapshotContentName: ""
source:
apiGroup: null
kind: PersistentVolumeClaim
name: pvc-nginx
status:
creationTime: "2021-04-05T13:22:48Z"
error:
message: 'Failed to create snapshot: selfLink was empty, can''t make reference'
time: "2021-04-05T13:23:11Z"
readyToUse: false
restoreSize: null

I am using snapshot.storage.k8s.io/v1alpha1, which is still included in k8s 1.20.

$ kubectl api-versions | grep snap
snapshot.storage.k8s.io/v1alpha1

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"20", GitVersion:"v1.20.5", GitCommit:"6b1d87acf3c8253c123756b9e61dac642678305f", GitTreeState:"clean", BuildDate:"2021-03-31T15:33:39Z", GoVersion:"go1.15.10", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"20", GitVersion:"v1.20.5", GitCommit:"6b1d87acf3c8253c123756b9e61dac642678305f", GitTreeState:"clean", BuildDate:"2021-03-31T16:42:32Z", GoVersion:"go1.15.10", Compiler:"gc", Platform:"linux/amd64"}

We are using: image: purestorage/k8s:5.2.0

It looks like this issue is referenced here, but I'm not sure how that helps us. Is an upgrade to PSO 6.x required?
kubernetes/kubernetes#94660

[aboje]

If it is true that we need to be on PSO 6.x, does PSO 5.x have any statement that it is incompatible with k8s 1.20?

[sdodsley]

PSO 5.x only supports the k8s alpha snapshot API. This was changed to the beta API from Kubernetes 1.17.
We will add a note to state this

[aboje]

Isn't that still available in k8s 1.20?

$ kubectl api-versions | grep snap
snapshot.storage.k8s.io/v1alpha1

[sdodsley]

That is interesting - Our understanding was that alpha APIs got dropping after n+2 from deprecation.
We have not tested PSO 5.x with k8s 1.20 as we only support this to k8s 1.17.
As noted the issue you see is fixed in the v2+ snapshotter which is used by PSO 6.
The upgrade process for PSO 5.2 to PSO 6.1 is detailed here.

[aboje]

Ok, I will start that process.