add healthz check to agent

[learner0810]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[karmada-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign rainbowmango after the PR has been reviewed.
You can assign the PR to them by writing /assign @rainbowmango 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:

• OWNERS

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

[learner0810]

/retest

[karmada-bot]

@learner0810: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/retest

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.

[RainbowMango]

Sorry, I missed this PR. Please cc me to trigger the test or by another push.

[RainbowMango]

Hi @learner0810
Can you also add the helthz to https://github.com/karmada-io/karmada/blob/master/artifacts/agent/karmada-agent.yaml, so it could be covered by our test?

[learner0810]

Hi @learner0810 Can you also add the helthz to https://github.com/karmada-io/karmada/blob/master/artifacts/agent/karmada-agent.yaml, so it could be covered by our test?

My pr is to solve this problem kubernetes-sigs/controller-runtime#297.

If the agent needs to add a health check, then it needs to bind a port. does karmada have a port plan?

https://github.com/kubernetes-sigs/controller-runtime/blob/4d10a0615b11507451ecb58bfd59f0f6ef313a29/pkg/manager/manager.go#L362

[RainbowMango]

I wonder how to use the HealthzCheck? If we didn't make use of it, then how to know if it works?

[learner0810]

I wonder how to use the HealthzCheck? If we didn't make use of it, then how to know if it works?

There is no way to confirm, if the agent pod does not add HealthzCheck, then this pr is not necessary and I will close this pr

[RainbowMango]

I haven't looked into the code.

controllerManager.AddHealthzCheck("ping", healthz.Ping)

What's this used for? What's the benefit? Can you give a simple description?

[RainbowMango]

@Garrybest Do you think this is needed for karmada-agent?

[Garrybest]

I suppose this check is duplicated, see

karmada/vendor/sigs.k8s.io/controller-runtime/pkg/healthz/healthz.go

Lines 68 to 72 in b4be8be

	// ...default a check if none is present...
	if len(h.Checks) == 0 {
	parts = append(parts, checkStatus{name: "ping", healthy: true})
	}

[RainbowMango]

I suppose this check is duplicated, see

Good to know. Yeah, I agree. So, let's close it. @learner0810 Thanks for doing this all the same.

/close

[karmada-bot]

@RainbowMango: Closed this PR.

In response to this:

I suppose this check is duplicated, see

Good to know. Yeah, I agree. So, let's close it. @learner0810 Thanks for doing this all the same.

/close

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.