Remove duplicate calculation nodename、hostname、hostnameOverridden when kubelet is initialized

[wawa0210]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Remove the repeated calculation of nodeName and hostname during kubelet startup, these parameters are all calculated in the RunKubelet method

kubernetes/cmd/kubelet/app/server.go

Lines 1053 to 1062 in e951061

	func RunKubelet(kubeServer *options.KubeletServer, kubeDeps *kubelet.Dependencies, runOnce bool) error {
	hostname, err := nodeutil.GetHostname(kubeServer.HostnameOverride)
	if err != nil {
	return err
	}
	// Query the cloud provider for our node name, default to hostname if kubeDeps.Cloud == nil
	nodeName, err := getNodeName(kubeDeps.Cloud, hostname)
	if err != nil {
	return err
	}

kubernetes/cmd/kubelet/app/server.go

Lines 947 to 965 in e951061

	func getNodeName(cloud cloudprovider.Interface, hostname string) (types.NodeName, error) {
	if cloud == nil {
	return types.NodeName(hostname), nil
	}
	instances, ok := cloud.Instances()
	if !ok {
	return "", fmt.Errorf("failed to get instances from cloud provider")
	}
	nodeName, err := instances.CurrentNodeName(context.TODO(), hostname)
	if err != nil {
	return "", fmt.Errorf("error fetching current node name from cloud provider: %v", err)
	}
	klog.V(2).Infof("cloud provider determined current node name to be %s", nodeName)
	return nodeName, nil
	}

So the subsequent process does not need to be repeated

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

/assign @vishh

[mtaufen]

/assign @liggitt

The host/node name logic is rather complex and I've been wrong about how it works before. @liggitt has some history with these fields IIRC - PTAL.

[liggitt]

this looks correct. suggest doing the same plumbing hostname and hostnameOverridden in instead of recomputing

[liggitt]

Suggested change

	kubeServer.HostnameOverride,
	nodeName,
	hostname,
	len(kubeServer.HostnameOverride) > 0,
	nodeName,

[liggitt]

Suggested change

	hostnameOverride string,
	nodeName types.NodeName,
	hostname string,
	hostnameOverridden bool,
	nodeName types.NodeName,

[liggitt]

Suggested change

	hostnameOverride,
	nodeName,
	hostname,
	hostnameOverridden,
	nodeName,

[liggitt]

Suggested change

	hostnameOverride string,
	nodeName types.NodeName,
	hostname string,
	hostnameOverridden string,
	nodeName types.NodeName,

[wawa0210]

Thank you very much, very good advice, so that hostname, nodename, hostnameOverridden can avoid double compute, has been completed

[liggitt]

/lgtm
/approve
/priority backlog

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt, wawa0210

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• cmd/kubelet/OWNERS [liggitt]
• pkg/kubelet/OWNERS [liggitt]

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