kubelet: fix fail to close kubelet->API connections on heartbeat failure

[gaorong]

What type of PR is this?
/kind bug

What this PR does / why we need it:
After #63492, we gain the ability to force close connections on heartbeat failure, when heartbeat failed, we invoke closeAllConns and reestablish new connections. But there is a regression imported by #71174, which assign nil to closeAllConns when bootstrapping or client certificate rotation is disabled. So the broken connection cannot be closed correctly and reused by latter request.
This seems a critical problem because the disconnection to API server can cause cluster-level failure. In an edge case, all nodes turn to NotReady status at the same time.
There are some related issues: kubernetes/client-go#374, #65012.

As discussed in kubernetes/client-go#374, another way to fix this is using http/2.0's ping frame to keep connection alive and identify failed connections. but it seems to be a long-term solution.

Which issue(s) this PR fixes:

Special notes for your reviewer:
the default value of connrotation.NewDialer((&net.Dialer{Timeout: 30 * time.Second, KeepAlive: 30 * time.Second}).DialContext) is 30s. jsut align default value from here and it seems work well for a long time.

related integration test is onging: #77957

Does this PR introduce a user-facing change?:

kubelet: fix fail to close kubelet->API connections on heartbeat failure when bootstrapping or client certificate rotation is disabled

@liggitt @smarterclayton @lavalamp @roycaihw @jfoy @hzxuzhonghu

[k8s-ci-robot]

Hi @gaorong. 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[mattjmcnaughton]

/ok-to-test

[lavalamp]

cc @roycaihw

[gaorong]

the CI is green now

[liggitt]

/kind bug
/priority important-soon
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gaorong, liggitt

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

The pull request process is described here

Needs approval from an approver in each of these files:

• cmd/kubelet/OWNERS [liggitt]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[liggitt]

thanks. once this merges, can you pick it to the release-1.14 branch with hack/cherry_pick_pull.sh?

[tedyu]

In the description:

ping fame -> ping frame

[gaorong]

thanks. once this merges, can you pick it to the release-1.14 branch with hack/cherry_pick_pull.sh?

sure, I'll work on this.

[chestack]

how about kube-proxy which has the name issue. Is there any plan to fix it.