New NodeUnpublish check in the CSI sanity test suite

[Jonathan Dobson]

Hi all,

For CSI driver authors, and other consumers of the csi-sanity test suite:

With the following PR merged, the CSI sanity test now supports validating that TargetPath is cleaned up as part of NodeUnpublish.

https://github.com/kubernetes-csi/csi-test/pull/338

Why? The CSI spec states that the SP MUST delete the file or directory that it created as part of NodeUnpublishVolume. This adds a new scenario to the sanity test to verify that NodeUnpublishVolume removes TargetPath.

Actions needed:

1) If you maintain a driver, please ensure that NodeUnpublishVolume adheres to the spec and removes the TargetPath. Removal of TargetPath by the kubelet will be deprecated starting in Kubernetes 1.22 (see https://github.com/kubernetes/kubernetes/pull/101441) and this should be handled by the driver instead.

2) If you are using using the --csi.createmountpathcmd CLI option with csi-sanity, this test will be skipped until you add the --csi.checkpathcmd CLI option to provide a way to check whether a given path exists. The same is true for consumers using custom callback functions as part of TestConfig (i.e. CreateTargetDir and CheckPath).

Thank you.