Add Etcd client support: stop traffic to in-defragmentation-server

[Yiqing-Liu]

What would you like to be added?

Etcd defragmentation is the workflow to prevent etcd from running out of disk space.
It is expected that defragmentation will result in timeouts and latency to requests that happen to be connected to the node being defragmented.

There is a proposal to stop traffic sending to being-defragmented-etcd-node.
etcd-io/etcd#16278

The Etcd server's implementation has been merged in etcd-io/etcd#17914, which is guarded by a feature flag.

Propose client side make the corresponding change (which can be guarded by feature flag as well) to complete the implementation.

Why is this needed?

This work will largely mitigate the Etcd defrag impact, decreasing the 5xx error rate.
to address the reported issue: #93280

[k8s-ci-robot]

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[pranav-pandey0804]

/sig api-machinery

[cici37]

/sig etcd
/remove-sig api-machinery

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/lifecycle stale

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/lifecycle rotten

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/close not-planned

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue, marking it as "Not Planned".

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Reopen this issue with /reopen
• Mark this issue as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/close not-planned

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