[Feature request]: Support reloading TLS certificates

[kwohlfahrt]

What would you like to be added?

The TLS certificates for the server are loaded only once on startup, see here. This means if the certificate is rotated (e.g. due to expiry), the server will not pick up the new certificate.

Instead, the certificate should be reloaded when the file on disk changes.

Why is this needed?

The kube-apiserver process can't start if the file specified in --authentication-token-webhook-config-file does not exist.

This makes relying on the server to provision certificates a problem during bootstrapping - the apiserver needs the config file to start, and the daemonset needs the apiserver to be up to be deployed.

One way around this is to provision the certificate with some external system, which is then also responsible for rotating the certificate when it is about to expire.

Anything else we need to know?

Certificate reloading functionality is available in the certwatcher package. I'm happy to open a PR integrating this.

[k8s-triage-robot]

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/lifecycle stale

[kwohlfahrt]

/remove-lifecycle stale

[k8s-triage-robot]

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

This bot triages un-triaged 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:

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

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

/lifecycle stale

[k8s-triage-robot]

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

This bot triages un-triaged 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

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/lifecycle rotten

[k8s-triage-robot]

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
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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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