sleep before shutdown

[wuzhuoquan]

What this PR does / why we need it:

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] CVE Report (Scanner found CVE and adding report)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation only

Which issue/s this PR fixes

How Has This Been Tested?

The ingress-controller deploy in k8s cluster,when deleting the ingress-controller pod, k8s controller will remove this pod from endpoint list, and then the container execute waitshutdown to sent SIGTERM to the nginx-ingress-controller process according the preStop setting.

After remove the pod from endpoint list, kube-proxy listwatch the change of endpoint and update the iptables rule to remove the pod IP.

But sometimes kube-proxy and iptables remote the pod and ip not as fast as executing waitshutdown, so if at this time,a new connection request may be send to the deleting pod but waitshutdown is executed,will return connection refused to client.

So I think before sent SIGTERM to the nginx-ingress-controller process, it should sleep for a while to avoid this problem and make it more smooth.

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I've read the CONTRIBUTION guide
• [ ] I have added unit and/or e2e tests to cover my changes.
• [ ] All new and existing tests passed.

[k8s-ci-robot]

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[k8s-ci-robot]

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[k8s-ci-robot]

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[netlify[bot]]

✅ Deploy Preview for kubernetes-ingress-nginx canceled.

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[Gacko]

We recently had a discussion about this for a different reason (AWS NLB) and came to the conclusion that a wait, at least such a static value, is not a good way to solve this and the actual value might vary from use-case to use-case.

You can read more here: https://github.com/kubernetes/ingress-nginx/issues/11890.

I therefore close this PR and ask you to implement this on your own in the according chart value.