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🐛 prevent leader election when shutting down a non-elected manager #2724

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merged 1 commit into from Apr 2, 2024
Merged

🐛 prevent leader election when shutting down a non-elected manager #2724

merged 1 commit into from Apr 2, 2024

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alexandremahdhaoui
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@alexandremahdhaoui alexandremahdhaoui commented Mar 23, 2024 •
edited

Context

This PR should address a bug where the runnable group for Leader Election would start while shutting down the manager: #2719

What's happening?

However when leader election is enabled, a non-leader manager will never start the LeaderElection runnable group. Thus, the sync.Once allow starting a new election during shutdown. The change in this PR ensures Start is ineffective during shutdown.

Changes

  • On shutdown, perform a noop call to the sync.Once func associated with the LeaderElection runnableGroup to prevent it from starting a new leader election.

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linux-foundation-easycla bot commented Mar 23, 2024 •
edited

CLA Signed

The committers listed above are authorized under a signed CLA.

  • ✅ login: alexandremahdhaoui / name: Alexandre Mahdhaoui (d0c20b4)

@k8s-ci-robot k8s-ci-robot added the cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. label Mar 23, 2024
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Welcome @alexandremahdhaoui!

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Hi @alexandremahdhaoui. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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@k8s-ci-robot k8s-ci-robot added needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. and removed cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. labels Mar 23, 2024
@alexandremahdhaoui alexandremahdhaoui changed the title 🐛 prevent new leader election when a non-elected manager is shutting down #2719 🐛 prevent new leader election when a non-elected manager is shutting down Mar 23, 2024
@alexandremahdhaoui alexandremahdhaoui changed the title 🐛 prevent new leader election when a non-elected manager is shutting down 🐛 prevent leader election when shutting down a non-elected manager Mar 23, 2024
@alexandremahdhaoui alexandremahdhaoui force-pushed the fix-non-elected-shutdown branch 2 times, most recently from 4ef9863 to 49681ff Compare March 23, 2024 17:32
alvaroaleman
alvaroaleman reviewed Mar 24, 2024
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/ok-to-test

pkg/manager/internal.go
@@ -518,6 +518,8 @@ func (cm *controllerManager) engageStopProcedure(stopComplete <-chan struct{}) e

// Stop all the leader election runnables, which includes reconcilers.
cm.logger.Info("Stopping and waiting for leader election runnables")
// Prevent leader election when shutting down a non-elected manager
cm.runnables.LeaderElection.startOnce.Do(func() {})
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Could you add a test, please?

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Added the test in 06d575d.

@k8s-ci-robot k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Mar 24, 2024
@k8s-ci-robot k8s-ci-robot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. and removed size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. labels Mar 24, 2024
inteon
inteon reviewed Mar 25, 2024
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pkg/manager/manager_test.go

Expect(m1.Add(RunnableFunc(func(ctx context.Context) error {
defer GinkgoRecover()
return nil
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Can you simulate a Runnable that blocks until the context is canceled?

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& make sure it is stopped before manager.Start returns?

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[Edit] Done

@alexandremahdhaoui
🐛 prevent leader election when shutting down a non-elected manager
d0c20b4 
When leader election is enabled, a non-leader manager would never start the LeaderElection runnable group.
Thus, as the shutdown process calls the sync.Once Start func of the runnableGroup; it will start a new election.
This change ensures `Start` is ineffective during shutdown.

The test ensures the LeaderElection runnableGroup is not started during shutdown.

Signed-off-by: Alexandre Mahdhaoui <alexandre.mahdhaoui@gmail.com>
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vincepri commented Apr 2, 2024

/lgtm

@k8s-ci-robot k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Apr 2, 2024
alvaroaleman
alvaroaleman approved these changes Apr 2, 2024
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/cherrypick release-0.17

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alexandremahdhaoui, alvaroaleman

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@k8s-ci-robot k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Apr 2, 2024
@k8s-ci-robot k8s-ci-robot merged commit a2a90a8 into kubernetes-sigs:main Apr 2, 2024
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/cherrypick release-0.17

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@alvaroaleman: new pull request created: #2752

In response to this:

/cherrypick release-0.17

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@k8s-infra-cherrypick-robot k8s-infra-cherrypick-robot mentioned this pull request Apr 2, 2024
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@alvaroaleman alvaroaleman alvaroaleman approved these changes

@varshaprasad96 varshaprasad96 Awaiting requested review from varshaprasad96

@inteon inteon Awaiting requested review from inteon

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