examples.md

Examples

Flatcar Linux Update Agent

The following example shows how to configure the maintenance-controller to perform OS patching for Flatcar Linux nodes. The example requires the Flatcar Linux Update Agent is installed in the cluster.

Configuration

intervals:
  requeue: 60s
  notify: 5h
instances:
  notify:
  - type: slack
    name: approval_required
    config:
      hook: Your hook
      channel: Your channel
      message: |
        The node {{ .Node.Name }} requires maintenance. Manual approval is required.
        Approve to drain and reboot this node by running:
        `kubectl annotate node {{ .Node.Name }} cloud.sap/maintenance-approved=true`
    schedule:
      type: periodic
      config:
        interval: 24h
  - type: slack
    name: maintenance_started
    config:
      hook: Your hook
      channel: Your channel
      message: |
        Maintenance for node {{ .Node.Name }} has started.
    schedule:
      type: periodic
      config:
        interval: 24h
  check:
  - type: hasAnnotation
    name: reboot_needed
    config:
      key: flatcar-linux-update.v1.flatcar-linux.net/reboot-needed
      value: "true"
  - type: hasAnnotation
    name: check_approval
    config:
      key: cloud.sap/maintenance-approved
      value: "true"
  trigger:
  - type: alterAnnotation
    name: reboot-ok
    config:
      key: flatcar-linux-update.v1.flatcar-linux.net/reboot-ok
      value: "true"
  - type: alterAnnotation
    name: remove_approval
    config:
      key: cloud.sap/maintenance-approved
      remove: true
  - type: alterAnnotation
    name: remove_reboot_ok
    config:
      key: flatcar-linux-update.v1.flatcar-linux.net/reboot-ok
      remove: true
profiles:
- name: flatcar
  operational:
    transitions:
    - check: reboot_needed
      next: maintenance-required
  maintenance-required:
    notify: approval_required
    transitions:
    - check: check_approval
      trigger: remove_approval && reboot-ok
      next: in-maintenance
  in-maintenance:
    notify: maintenance_started
    transitions:
    - check: "!reboot_needed"
      trigger: remove_reboot_ok
      next: operational

Explanation

Nodes in the flatcar profile transition from operational to maintenance-required if they require a reboot. Administrators are notified that manual approval is required. Then nodes wait for manual approval before transitioning to the in-maintenance state. The approval is given by setting the cloud.sap/maintenance-approved annotation to true. After maintenance is complete, nodes transition back to the operational state.