Change:
defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.CSIMigrationGCE, tc.csiMigration)() defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.InTreePluginGCEUnregister, tc.csiMigration)() <del> plugins = gcepd.ProbeVolumePlugins() </del> <ins> // if InTreePluginGCEUnregister is enabled, only the CSI plugin is registered but not the in-tree one </ins> plugins = append(plugins, csi.ProbeVolumePlugins()...) } else { plugins = controllervolumetesting.CreateTestPlugin()

Discussion:
<!-- Please use this template while reporting a bug and provide as much info as possible. Not doing so may result in your bug not being addressed in a timely manner. Thanks! If the matter is security related, please disclose it privately via --Context: When a cluster has dangling s caused by restarts of kube-controller-manager (like described in ), the attach/detach controller tries to clean them up on startup (ref ). For this, it iterates over all s and finds the responsible volume plugin for retrieving the unique volume name. Problem: However, if the volume was provisioned by an in-tree plugin, then later migrated to CSI and now the / feature gate is set, the volume is skipped during , so the will stay in the system and the volume will not be detached from the undesired node and potentially block a new attach operation to a different node. Analysis: The / feature gate causes the respective in-tree volume plugins not to be registered: The spec only contains the in-tree fields (e.g or ), but not the fields: This causes the call in to find no responsible volume plugin for the , which will skip the cleanup: That's why we see a lot of logs like this on startup of kube-controller-manager and dangling s on our clusters: The attach/detach controller should cleanup dangling s for migrated in-tree plugins with unregistered in-tree plugins as well. ref , addresses a similar issue. Though, the fix doesn't come into effect, if the respective / feature gate is enabled. Kubernetes version (use ): / Cloud provider or hardware configuration: AWS, GCP
/sig storage cc
Hey, thanks for reporting this bug!! I will try to come up with a fix. BTW, wondering what's the symptom you observed except for the log. Is there any volume operation(attaching/detaching/mounting/unmounting/creation/deletion) not working? This, to my understanding, will only make dangling attachment not working properly but I guess normal operation should work, is it?
The consequence of the leftover s in our case is that volumes are not detached on infrastructure provider side when moving pods with volumes between nodes, e.g.

because of rolling updates/eviction/etc.. This in turn causes the new s on the new nodes to fail with logs similar to this one: (we observe the same for GCP) I can also work on a fix tomorrow, if you want. I think, we should be able to reuse the fix from and additionally determine the from or similar, instead of only relying on .
That would be nice! Really appreciate it. Yep, sounds like a good idea. If you could also help to verify the fix in your environment that would be awesome
Ok, great. Will try to come up with a fix. /assign Definitely! I'll try my best and let you know if I need some help :)
Yep, we observed this after experiencing the bug. We ended up manually creating a cleanup script to check EC2 <-K8s VA if it was actually attached or not, otherwise delete VA. My understanding is with fixed we will no longer have this issue, but it would be nice to have the garbage collection logic work for migrated/non-migrated volumes regardless
/triage accepted