Add etcd WithRequireLeader option to API watches #89881
Merged
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
release-note-none
k8s-ci-robot
added
the
lgtm
wojtek-t
reviewed
Apr 6, 2020
k8s-ci-robot
added
do-not-merge/hold
|
/priority important-soon |
k8s-ci-robot
added
priority/important-soon
|
/assign @wojtek-t |
k8s-ci-robot
added
the
lgtm
Watches against etcd in the API server can hang forever if the etcd cluster loses quorum, e.g. the majority of nodes crashes. This fix improves responsiveness (detection and reaction time) of API server watches against etcd in some rare (but still possible) edge cases so that watches are terminated with `"etcdserver: no leader" (ErrNoLeader)`. Implementation behavior described by jingyih: ``` The etcd server waits until it cannot find a leader for 3 election timeouts to cancel existing streams. 3 is currently a hard coded constant. The election timeout defaults to 1000ms. If the cluster is healthy, when the leader is stopped, the leadership transfer should be smooth. (leader transfers its leadership before stopping). If leader is hard killed, other servers will take an election timeout to realize leader lost and start campaign. ``` For further details, discussion and validation see #89488 (comment) and etcd-io/etcd#8980. Closes: #89488 Signed-off-by: Michael Gasch <mgasch@vmware.com>
k8s-ci-robot
added
size/S
|
/hold cancel |
k8s-ci-robot
added
lgtm
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: dims, embano1, wojtek-t 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 |
k8s-ci-robot
added
the
approved
|
@embano1: The following test failed, say
Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR. Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here. |
|
/retest Review the full test history for this PR. Silence the bot with an |
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.
What type of PR is this?
/kind feature
What this PR does / why we need it:
Watches against etcd in the API server can hang forever if the etcd
cluster loses quorum, e.g. the majority of nodes crashes. This fix
improves responsiveness (detection and reaction time) of API server
watches against etcd in some rare (but still possible) edge cases so
that watches are terminated with
"etcdserver: no leader" (ErrNoLeader).Implementation behavior described by @jingyih:
For further details, discussion and validation see
#89488 (comment)
and etcd-io/etcd#8980.
Signed-off-by: Michael Gasch mgasch@vmware.com
Which issue(s) this PR fixes:
Fixes #89488
Does this PR introduce a user-facing change?:
/sig api-machinery
cc/ @dims @jingyih