struct hostPathPlugin contains newRecyclerFunc, newDeleterFunc and newProvisionerFunc items that have only one instance, i.e. newRecycler, newDeleter or newProvisioner function.
That's why the newRecyclerFunc, newDeleterFunc and newProvisionerFunc items are removed and the newRecycler, newDeleter or newProvisioner functions are called directly.
In addition, the TestRecycler tests whether NewFakeRecycler function is called and returns nil. This is no longer needed so this particular part of the test is removed. In addition, the no longer used NewFakeRecycler function is removed also.
Similarly for the NFS plugin, struct nfsPlugin contains newRecyclerFunc item that has only one instance, i.e. newRecycler function. That's why the newRecyclerFunc item is removed and the newRecycler function is called directly. In addition, the TestRecycler tests whether newMockRecycler function is called and returns nil. This is no longer needed so this particular part of the test is removed. In addition, the no longer used newMockRecycler function is removed also.
This allows users to diagnose what's wrong with recycler. Recycler pods are
started automatically with a cryptic name and they are deleted immediately
when they finish.
kubectl describe pods will show:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
59m 59m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(5421800e-347b-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
53m 53m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(3c9809e5-347c-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
46m 46m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(250dd2a2-347d-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
40m 40m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(0d84ea33-347e-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
33m 33m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(f5fb63bf-347e-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
27m 27m 1 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Unable to mount volumes for pod "recycler-for-nfs_default(de7128fd-347f-11e6-a79b-3c970e965218)": timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
1h 3m 75 {persistentvolume-controller } Normal RecyclerPod Recycler pod: Successfully assigned recycler-for-nfs to 127.0.0.1
1h 3m 76 {persistentvolume-controller } Normal RecyclerPod Recycler pod: Pod was active on the node longer than specified deadline
1h 1m 12 {persistentvolume-controller } Warning RecyclerPod Recycler pod: Error syncing pod, skipping: timeout expired waiting for volumes to attach/mount for pod "recycler-for-nfs"/"default". list of unattached/unmounted volumes=[vol]
20m 1m 4 {persistentvolume-controller } Warning RecyclerPod (events with common reason combined)
These steps were necessary:
- added event watcher to volume.RecycleVolumeByWatchingPodUntilCompletion
- pass all these events through volume plugins to volume controller
- rework volume.RecycleVolumeByWatchingPodUntilCompletion unit tests to a table
(too much copy-paste)
- fix all unit tests along the way
This commit adds a new volume manager in kubelet that synchronizes
volume mount/unmount (and attach/detach, if attach/detach controller
is not enabled).
This eliminates the race conditions between the pod creation loop
and the orphaned volumes loops. It also removes the unmount/detach
from the `syncPod()` path so volume clean up never blocks the
`syncPod` loop.
Recycling is a long duration process and when the recycler controller is
restarted in the meantime, it should not start a new recycler pod if there is
one already running.
This means that the recycler pod must have deterministic name based on name
of the recycled PV, we then get name conflicts when creating the pod.
Two things need to be changed:
- recycler controller and recycler plugins must pass the PV.Name to place,
where the pod is created.
- create recycler pod with deterministic name and check "already exists" error.
When at it, remove useless 'resourceVersion' argument and make log messages
starting with lowercase.
- Add volume.MetricsProvider function to Volume interface.
- Add volume.MetricsDu for providing metrics via executing "du".
- Add volulme.MetricsNil for unsupported Volumes.
