Handle namespace deletion more gracefully in built-in controllers #84123
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
k8s-ci-robot
added
do-not-merge/work-in-progress
smarterclayton
force-pushed
the
terminating_cause
branch
from
524fc6a to
cffe4b6
Compare
k8s-ci-robot
added
area/apiserver
sig/api-machinery
smarterclayton
force-pushed
the
terminating_cause
branch
from
cffe4b6 to
f7d6c67
Compare
k8s-ci-robot
added
kind/api-change
smarterclayton
changed the title
k8s-ci-robot
added
size/L
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: smarterclayton The full list of commands accepted by this bot can be found here. The pull request process is described here
Needs approval from an approver in each of these files:
Approvers can indicate their approval by writing |
smarterclayton
force-pushed
the
terminating_cause
branch
from
d619699 to
ec9fdc4
Compare
|
This PR may require API review. If so, when the changes are ready, complete the pre-review checklist and request an API review. Status of requested reviews is tracked in the API Review project. |
…ting Clients should be able to identify when a namespace is being terminated and take special action such as backing off or giving up. Add a helper for getting the cause of an error and then add a special cause to the forbidden error that namespace lifecycle admission returns. We can't change the forbidden reason without potentially breaking older clients and so cause is the appropriate tool. Add `StatusCause` and `HasStatusCause` to the errors package to make checking for causes simpler. Add `NamespaceTerminatingCause` to the v1 API as a constant.
Avoid sending an event to the namespace that is being terminated, since it will be rejected.
In some scenarios the service account and token controllers can race with namespace deletion, causing a burst of errors as they attempt to recreate secrets being deleted. Instead, detect these errors and do not retry.
Instead of reporting an event or displaying an error, simply exit when the namespace is being terminated. This reduces the amount of controller churn on namespace shutdown. While we could technically exit the entire processing loop early for very large replica sets, we should wait for more evidence that is an issue before changing that logic substantially.
Instead of reporting an event or displaying an error, simply exit when the namespace is being terminated. This reduces the amount of controller churn on namespace shutdown. While we could technically exit the entire processing loop early for very large daemon sets, we should wait for more evidence that is an issue before changing that logic substantially.
Instead of reporting an event or displaying an error, simply exit when the namespace is being terminated. This reduces the amount of controller churn on namespace shutdown. While we could technically exit the entire processing loop early for very large jobs, we should wait for more evidence that is an issue before changing that logic substantially.
…sets Instead of reporting an event or displaying an error, simply exit when the namespace is being terminated. This reduces the amount of controller churn on namespace shutdown. Unlike other controllers, we drop the replica set create error very late (in the queue handleErr) in order to avoid changing the structure of the controller substantially.
smarterclayton
force-pushed
the
terminating_cause
branch
from
ec9fdc4 to
bd92607
Compare
|
/retest |
|
/test pull-kubernetes-e2e-gce |
|
/test pull-kubernetes-e2e-gce |
|
/retest |
|
/test pull-kubernetes-e2e-gce |
soltysh
approved these changes
Nov 4, 2019
| @@ -213,7 +213,10 @@ func (c *ServiceAccountsController) syncNamespace(key string) error { | |||
| sa.Namespace = ns.Name | |||
|
|
|||
| if _, err := c.client.CoreV1().ServiceAccounts(ns.Name).Create(&sa); err != nil && !apierrs.IsAlreadyExists(err) { | |||
| createFailures = append(createFailures, err) | |||
| // we can safely ignore terminating namespace errors | |||
| if !apierrs.HasStatusCause(err, v1.NamespaceTerminatingCause) { | |||
There was a problem hiding this comment.
Nit: this could be placed next to !apierrs.IsAlreadyExists(err)
| // pod when the expectation expires. | ||
| return nil | ||
| if err != nil { | ||
| if errors.HasStatusCause(err, v1.NamespaceTerminatingCause) { |
There was a problem hiding this comment.
Nit: not sure why you need to have two ifs if both return the same, comment for both handled in one should be sufficient.
k8s-ci-robot
added
do-not-merge/hold
tnozicka
approved these changes
Nov 4, 2019
| @@ -475,7 +475,7 @@ func (dc *DeploymentController) processNextWorkItem() bool { | |||
| } | |||
|
|
|||
| func (dc *DeploymentController) handleErr(err error, key interface{}) { | |||
| if err == nil { | |||
| if err == nil || errors.HasStatusCause(err, v1.NamespaceTerminatingCause) { | |||
There was a problem hiding this comment.
Will work only for unwrapped errors, but we might make it better when we get golang 1.13
I don't see the calls there wrapping the errors with context so this should be good for now
|
/hold cancel |
k8s-ci-robot
removed
the
do-not-merge/hold
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Kubernetes workload controllers deal poorly with namespaces being terminated and often go into tight backoff loops during shutdown. Since namespace termination cannot be reversed, for the majority of controllers when we detect this scenario we should eat / drop / exit the loop we are in and wait for more events. A more sophisticated mechanism could remember that a namespace was being terminated and dequeue all events that impact that namespace, but that also has to contend with races for a new namespace of the same name and is more invasive. In general, detect the namespace terminating error and exit fast, avoiding spawning other events or errors (since event creation is another example of a failure).
To make this possible, clients should be able to identify when a namespace is being terminated and
take special action such as backing off or giving up. Add a helper for getting the cause of an error and then add a special cause to the forbidden error that namespace lifecycle admission returns. We can't change the forbidden reason without potentially breaking older clients and so cause is the
appropriate tool.
This shows up in a lot of controllers during e2e runs. In theory this should take a ton of CPU pressure off the apiserver during e2e and speed up e2e runs.
/kind bug