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.
Automatic merge from submit-queue
Remove unused WaitForDetach from Detacher interface and plugins
See issue #33128 and PR #33270
We can't rely on the device name provided by OpenStack Cinder, and thus
must perform detection based on the drive serial number (aka It's cinder ID)
on the kubelet itself.
This needs to be removed now, as part of #33128, as the code can't be
updated to attempt device detection and fallback through to the Cinder
provided deviceName, as detection "fails" when the device is gone, and
if cinder has reported a deviceName that another volume has used in
relaity, then this will block forever (or until the other, unreleated,
volume has been detached)
This has been unused since 542f2dc7, and relies on deviceName, which
can no longer be relied upon (see issue #33128).
This needs to be removed now, as part of #33128, as the code can't be
updated to attempt device detection and fallback through to the Cinder
provided deviceName, as detection "fails" when the device is gone, and
if cinder has reported a deviceName that another volume has used in
relaity, then this will block forever (or until the other, unreleated,
volume has been detached)
At master volume reconciler, the information about which volumes are
attached to nodes is cached in actual state of world. However, this
information might be out of date in case that node is terminated (volume
is detached automatically). In this situation, reconciler assume volume
is still attached and will not issue attach operation when node comes
back. Pods created on those nodes will fail to mount.
This PR adds the logic to periodically sync up the truth for attached volumes kept in the actual state cache. If the volume is no longer attached to the node, the actual state will be updated to reflect the truth. In turn, reconciler will take actions if needed.
To avoid issuing many concurrent operations on cloud provider, this PR
tries to add batch operation to check whether a list of volumes are
attached to the node instead of one request per volume.
More details are explained in PR #33760
Gluster provisioner is interested in pvc.Namespace and I don't want to add
at as a new field in VolumeOptions - it would contain almost whole PVC.
Let's pass direct reference to PVC instead and let the provisioner to pick
information it is interested in.
We had another bug where we confused the hostname with the NodeName.
To avoid this happening again, and to make the code more
self-documenting, we use types.NodeName (a typedef alias for string)
whenever we are referring to the Node.Name.
A tedious but mechanical commit therefore, to change all uses of the
node name to use types.NodeName
Also clean up some of the (many) places where the NodeName is referred
to as a hostname (not true on AWS), or an instanceID (not true on GCE),
etc.
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
Automatic merge from submit-queue
Add volume reconstruct/cleanup logic in kubelet volume manager
Currently kubelet volume management works on the concept of desired
and actual world of states. The volume manager periodically compares the
two worlds and perform volume mount/unmount and/or attach/detach
operations. When kubelet restarts, the cache of those two worlds are
gone. Although desired world can be recovered through apiserver, actual
world can not be recovered which may cause some volumes cannot be cleaned
up if their information is deleted by apiserver. This change adds the
reconstruction of the actual world by reading the pod directories from
disk. The reconstructed volume information is added to both desired
world and actual world if it cannot be found in either world. The rest
logic would be as same as before, desired world populator may clean up
the volume entry if it is no longer in apiserver, and then volume
manager should invoke unmount to clean it up.
Fixes https://github.com/kubernetes/kubernetes/issues/27653
Currently kubelet volume management works on the concept of desired
and actual world of states. The volume manager periodically compares the
two worlds and perform volume mount/unmount and/or attach/detach
operations. When kubelet restarts, the cache of those two worlds are
gone. Although desired world can be recovered through apiserver, actual
world can not be recovered which may cause some volumes cannot be cleaned
up if their information is deleted by apiserver. This change adds the
reconstruction of the actual world by reading the pod directories from
disk. The reconstructed volume information is added to both desired
world and actual world if it cannot be found in either world. The rest
logic would be as same as before, desired world populator may clean up
the volume entry if it is no longer in apiserver, and then volume
manager should invoke unmount to clean it up.
Modify attach/detach controller to keep track of volumes to report
attached in Node VolumeToAttach status.
Modify kubelet volume manager to wait for volume to show up in Node
VolumeToAttach status.
Implement exponential backoff for errors in volume manager and attach
detach controller
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.
This PR contains Kubelet changes to enable attach/detach controller control.
* It introduces a new "enable-controller-attach-detach" kubelet flag to
enable control by controller. Default enabled.
* It removes all references "SafeToDetach" annoation from controller.
* It adds the new VolumesInUse field to the Node Status API object.
* It modifies the controller to use VolumesInUse instead of SafeToDetach
annotation to gate detachment.
* There is a bug in node-problem-detector that causes VolumesInUse to
get reset every 30 seconds. Issue https://github.com/kubernetes/node-problem-detector/issues/9
opened to fix that.
Split controller cache into actual and desired state of world.
Controller will only operate on volumes scheduled to nodes that
have the "volumes.kubernetes.io/controller-managed-attach" annotation.
Automatic merge from submit-queue
Add support for PersistentVolumeClaim in Attacher/Detacher interface
The attach detach interface does not support volumes which are referenced through PVCs. This PR adds that support
Automatic merge from submit-queue
volume recycler: Don't start a new recycler pod if one already exists.
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. This is most of the patch and it should be pretty straightforward.
- 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.
There is an unit test to check the behavior + there is an e2e test that checks that regular recycling is not broken (it does not try to run two recycler pods in parallel as the recycler is single-threaded now).
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.
Automatic merge from submit-queue
Refactor persistent volume controller
Here is complete persistent controller as designed in https://github.com/pmorie/pv-haxxz/blob/master/controller.go
It's feature complete and compatible with current binder/recycler/provisioner. No new features, it *should* be much more stable and predictable.
Testing
--
The unit test framework is quite complicated, still it was necessary to reach reasonable coverage (78% in `persistentvolume_controller.go`). The untested part are error cases, which are quite hard to test in reasonable way - sure, I can inject a VersionConflictError on any object update and check the error bubbles up to appropriate places, but the real test would be to run `syncClaim`/`syncVolume` again and check it recovers appropriately from the error in the next periodic sync. That's the hard part.
Organization
---
The PR starts with `rm -rf kubernetes/pkg/controller/persistentvolume`. I find it easier to read when I see only the new controller without old pieces scattered around.
[`types.go` from the old controller is reused to speed up matching a bit, the code looks solid and has 95% unit test coverage].
I tried to split the PR into smaller patches, let me know what you think.
~~TODO~~
--
* ~~Missing: provisioning, recycling~~.
* ~~Fix integration tests~~
* ~~Fix e2e tests~~
@kubernetes/sig-storage
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Fixes#15632
- Expand Attacher/Detacher interfaces to break up work more
explicitly.
- Add arguments to all functions to avoid having implementers store
the data needed for operations.
- Expand unit tests to check that Attach, Detach, WaitForAttach,
WaitForDetach, MountDevice, and UnmountDevice get call where
appropriet.
NickrenREN
