When the controller binds a PV to PVC, it saves both objects to etcd.
However, there is still an old version of these objects in the controller
Informer cache. So, when a new PVC comes, the PV is still seen as available
and may get bound to the new PVC. This will be blocked by etcd, still, it
creates unnecessary traffic that slows everything down.
Also, we save bound PV/PVC as two transactions - we save PV/PVC.Spec first
and then .Status. The controller gets "PV/PVC.Spec updated" event from etcd
and tries to fix the Status, as it seems to the controller it's outdated.
This write again fails - there already is a correct version in etcd.
We can't influence the Informer cache, it is read-only to the controller.
To prevent these useless writes to etcd, this patch introduces second cache
in the controller, which holds latest and greatest version on PVs and PVCs.
It gets updated with events from etcd *and* after etcd confirms successful
save of PV/PVC modified by the controller.
The cache stores only *pointers* to PVs/PVCs, so in ideal case it shares the
actual object data with the informer cache. They will diverge only when
the controller modifies something and the informer cache did not get update
events yet.
Automatic merge from submit-queue
AWS: Move enforcement of attached AWS device limit from kubelet to scheduler
Limit of nr. of attached EBS volumes to a node is now enforced by scheduler. It can be adjusted by `KUBE_MAX_PD_VOLS` env. variable there. Therefore we don't need the same check in kubelet. If the system admin wants to attach more, we should allow it.
Kubelet limit is now 650 attached volumes ('ba'..'zz').
Note that the scheduler counts only *pods* assigned to a node. When a pod is deleted and a new pod is scheduled on a node, kubelet start (slowly) detaching the old volume and (slowly) attaching the new volume. Depending on AWS speed **it may happen that more than KUBE_MAX_PD_VOLS volumes are actually attached to a node for some time!** Kubelet will clean it up in few seconds / minutes (both attach/detach is quite slow).
Fixes#22994
Automatic merge from submit-queue
kube-apiserver options should be decoupled from impls
A few months ago we refactored options to keep it independent of the
implementations, so that it could be used in CLI tools to validate
config or to generate config, without pulling in the full dependency
tree of the master. This change restores that by separating
server_run_options.go back to its own package.
Also, options structs should never contain non-serializable types, which
storagebackend.Config was doing with runtime.Codec. Split the codec out.
Fix a typo on the name of the etcd2.go storage backend.
Finally, move DefaultStorageMediaType to server_run_options.
@nikhiljindal as per my comment in #24454, @liggitt because you and I
discussed this last time
Sometimes clients send unintelligible data to the server, provide a bit
more debugging in the returned error to make it easier to pin down where
the problem is from the user side.
Provides fast transformations of int64 scaled values with overflow to
inf.Dec as needed. Attempts to reduce allocations and expensive
operations in the critical path.
Alters the public signature of Quantity to encourage more efficient use
Using volume/claim.UID in the operation name is not really useful, as UIDs
are not logged by rest of the controller. On the other hand, volume.Name and
claim.Namespace/Name is logged pretty often and it would help to log these
also in operation name.
This has been already proven to be very useful in controller debugging.
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
Automatic merge from submit-queue
Make name validators return string slices
Part of the larger validation PR, broken out for easier review and merge. Builds on previous PRs in the series.
This patch adds the --exit-on-lock-contention flag, which must be used
in conjunction with the --lock-file flag. When provided, it causes the
kubelet to wait for inotify events for that lock file. When an 'open'
event is received, the kubelet will exit.
When the IP isn't in the internal map, GetPodNetworkStatus() needs
to call the execer for the 'nsenter' program. That means the execer
needs to be !nil, which it wasn't before.
A few months ago we refactored options to keep it independent of the
implementations, so that it could be used in CLI tools to validate
config or to generate config, without pulling in the full dependency
tree of the master. This change restores that by separating
server_run_options.go back to its own package.
Also, options structs should never contain non-serializable types, which
storagebackend.Config was doing with runtime.Codec. Split the codec out.
Fix a typo on the name of the etcd2.go storage backend.
Finally, move DefaultStorageMediaType to server_run_options.
The key to path mapping allows pod to specify different name (thus location) of each secret.
At the same time refactor the volume plugin to use AtomicWritter to project secrets to files in a volume.
Update e2e Secrets test, the secret file permission has changed from 0444 to 0644
Remove TestPluginIdempotent as the AtomicWritter is responsible for secret creation
Automatic merge from submit-queue
Make IsValidLabelValue return error strings
Part of the larger validation PR, broken out for easier review and merge. Builds on previous PRs in the series.
- remove persistentvolume_ prefix from all files
- split controller.go into controller.go and controller_base.go (to have them
under 1500 lines for github)
