feat: add trigger to restart kube-apiserver when config files change

[hhk7734]

What type of PR is this?

/kind feature

What this PR does / why we need it:

When the kube-apiserver config files change, some users may not realize that they need to manually restart the kube-apiserver because the manifest itself remains unchanged and kubelet does not automatically restart the Pod.

With this PR, even if the manifest is not modified, the kube-apiserver will be restarted whenever related config files change.

For example, if audit_policy_custom_rules is modified and ansible-playbook upgrade-cluster.yml --tags master is run, the kube-apiserver will be automatically restarted to apply the updated audit policies.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

None

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[VannTen]

Are you sure the kube-apiserver isn't reloading changed config file dynamically ? If I recall correctly, I was told that at least for structured authentication.
If not, you should use an handler instead of register + when.

[hhk7734]

Here's how I tested it:

kubernetes_audit: true
audit_policy_custom_rules: |
  - level: Metadata

ansible-playbook -i inventory -b -e "@kubespray_vars.yaml" cluster.yml

After creating a cluster, I confirmed that auditing was working by checking /var/log/kubernetes/audit/kube-apiserver-audit.log.
The log file was created and contained audit records as expected.

kubernetes_audit: true
audit_policy_custom_rules: |
  - level: None

ansible-playbook -i inventory -b -e "@kubespray_vars.yaml" upgrade-cluster.yml --tags master

After applying the changes, I noticed that although the /etc/kubernetes/audit-policy/apiserver-audit-policy.yaml file was updated, the new settings were not applied. Events were still being logged in /var/log/kubernetes/audit/kube-apiserver-audit.log.

After applying this PR, I deleted the contents of /etc/kubernetes/audit-policy/apiserver-audit-policy.yaml and ran the following command again:

ansible-playbook -i inventory -b -e "@kubespray_vars.yaml" upgrade-cluster.yml --tags master

This time, the changes were applied correctly.

[hhk7734]

Should I change it to this?

- name: Write api audit policy yaml
  template:
    src: apiserver-audit-policy.yaml.j2
    dest: "{{ audit_policy_file }}"
    mode: "0640"
  register: apiserver_audit_policy_update
  when: kubernetes_audit | default(false) or kubernetes_audit_webhook | default(false)
  notify: Control plane | Restart apiserver

[VannTen]

Ok, thanks for testing 👍
Yeah looks fine, just unless the apiserver_audit_policy_update is used you can scrap it.

[VannTen]

/ok-to-test
I had forgot about that, sry

[yankay]

/retest-failed

[hhk7734]

/retest

[VannTen]

This looks fine, thanks !
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hhk7734, VannTen

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