add leader elect args

[gujingit]

What type of PR is this?

/kind feature

What this PR does / why we need it

Which issue(s) this PR fixes

Fixes #19

Special notes for your reviewer

Does this PR introduce a user-facing change?

[k8s-ci-robot]

Hi @gujingit. 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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[kerthcet]

/ok-to-test

[liurupeng]

Were you able to test manually to verify the leader election functionality work as expected? @gujingit

[gujingit]

Were you able to test manually to verify the leader election functionality work as expected? @gujingit

Test 1: deploy lws-controller-manager with 2 replicas

1. Deploy lws-controller-manager with 2 replicas

NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
lws-controller-manager   2/2     2            2           28m

2. Deploy a simple lws application

kubectl apply -f docs/examples/sample/lws.yaml 

outputs

NAME                         READY   STATUS    RESTARTS   AGE
leaderworkerset-sample-0     1/1     Running   0          9s
leaderworkerset-sample-0-1   1/1     Running   0          9s
leaderworkerset-sample-0-2   1/1     Running   0          9s
leaderworkerset-sample-0-3   1/1     Running   0          9s
leaderworkerset-sample-1     1/1     Running   0          9s
leaderworkerset-sample-1-1   1/1     Running   0          9s
leaderworkerset-sample-1-2   1/1     Running   0          9s
leaderworkerset-sample-1-3   1/1     Running   0          9s
leaderworkerset-sample-2     1/1     Running   0          9s
leaderworkerset-sample-2-1   1/1     Running   0          9s
leaderworkerset-sample-2-2   1/1     Running   0          9s
leaderworkerset-sample-2-3   1/1     Running   0          9s

Test 2: Leader election lost

1. Get the current leader

NAME                                      READY   STATUS    RESTARTS   AGE
lws-controller-manager-77489f74b8-74mwv   2/2     Running   0          8m19s
lws-controller-manager-77489f74b8-qs288   2/2     Running   0          8m40s

leader

kubectl -n lws-system get lease b8b2488c.x-k8s.io
####
NAME                HOLDER                                                                         AGE
b8b2488c.x-k8s.io   lws-controller-manager-77489f74b8-qs288_7f45752d-2de4-4da8-ab31-7313dc04f1ff   29m

2. Kill the leader pod

kubectl  -n lws-system delete po lws-controller-manager-77489f74b8-qs288

The leader was changed to the other pod automatically

kubectl -n lws-system get lease b8b2488c.x-k8s.io
####
NAME                HOLDER                                                                         AGE
b8b2488c.x-k8s.io   lws-controller-manager-77489f74b8-74mwv_2d1b2863-e787-42e6-af13-71eb2a9aae9f   31m

[liurupeng]

/lgtm
/approve

[kerthcet]

/hold

Should we make this the default behavior?

[liurupeng]

/hold

Should we make this the default behavior?

I think so, but do you know what might be the downside for that?

[kerthcet]

Nothing special
/hold cancel

[liurupeng]

/lgtm
/approve

Thanks @gujingit

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gujingit, liurupeng

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