Add the existence check before requeueing node which failed in updateCIDRsAllocation

[Sophichia]

What type of PR is this?
/kind bug

What this PR does / why we need it:
It checks whether the node is still existing before requeueing it into the next round of updateCIDRsAllocation.
If the range_allocator doesn't have this check, it may have a possibility that keeps requeueing updateCIDRsAllocation for a node that is already be removed.

Which issue(s) this PR fixes:
In one scale environment, we hit the issue that one of the control plane nodes almost takes up 100% usage.
The process that eats most CPU is kube-controller-manager

# ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head

....
10336 10318 kube-controller-manager --a  2.6 83.1
....

When checking the log for kube-controller-manager pod deployed on this control plane node, it keeps printing out

E0129 06:45:42.778722       1 range_allocator.go:338] Failed while getting node worker-node-g8wd4 for updating Node.Spec.PodCIDRs: node "worker-node-g8wd4" not found
E0129 06:45:42.778732       1 range_allocator.go:338] Failed while getting node worker-node-g8wd4 for updating Node.Spec.PodCIDRs: node "worker-node-g8wd4" not found
E0129 06:45:42.778744       1 range_allocator.go:338] Failed while getting node worker-node-g8wd4 for updating Node.Spec.PodCIDRs: node "worker-node-g8wd4" not found
E0129 06:45:42.778756       1 range_allocator.go:338] Failed while getting node worker-node-g8wd4 for updating Node.Spec.PodCIDRs: node "worker-node-g8wd4" not found

From the above log, we can find the range_allocator tries to do updateCIDRsAllocation every other 20 microseconds. However, the worker-node-g8wd4 is actually not existing anymore in this cluster now.

The workaround for this issue is just to restart this pod.

Does this PR introduce a user-facing change?:
Nope.

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[k8s-ci-robot]

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[k8s-ci-robot]

Hi @Sophichia. Thanks for your PR.

I'm waiting for a kubernetes 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]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Sophichia
To complete the pull request process, please assign bowei after the PR has been reviewed.
You can assign the PR to them by writing /assign @bowei in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• pkg/controller/nodeipam/ipam/OWNERS

Approvers can indicate their approval by writing /approve in a comment
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[andrewsykim]

/assign

[andrewsykim]

/ok-to-test

[andrewsykim]

Thinking that updateCIDRsAllocation should have a second return value shouldRetry bool as opposed to inspecting the error here. What do you think?

[andrewsykim]

On second thought, I think if node is not found in updateCIDRsAllocation, we should attempt to release the cidr similar to what is done on line 385 - 392:

https://github.com/kubernetes/kubernetes/blob/82738f15cfe22b2aca2de2f1a78ef87f271684fb/pkg/controller/nodeipam/ipam/range_allocator.go#L385-L392

[andrewsykim]

/triage accepted

[k8s-ci-robot]

@Sophichia: The following tests failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
pull-kubernetes-typecheck	5a259a4	link	/test pull-kubernetes-typecheck
pull-kubernetes-e2e-kind	5a259a4	link	/test pull-kubernetes-e2e-kind

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.

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[fejta-bot]

Issues go stale after 90d of inactivity.
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Send feedback to sig-contributor-experience at kubernetes/community.
/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
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Send feedback to sig-contributor-experience at kubernetes/community.
/lifecycle rotten

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Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
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/close

[k8s-ci-robot]

@fejta-bot: Closed this PR.

In response to this:

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/close

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