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.
Harry Zhang
