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Ansible Role linuxfabrik.lfops.schedule_reboot

This role provides a single, windowed reboot mechanism for a host. A reboot is requested by dropping a file into a spool directory (/run/schedule-reboot/), and one do-reboot actor, triggered by a systemd timer at a configurable maintenance window, performs a single reboot for all pending requests. An ad-hoc schedule-reboot command is available to request a reboot after a manual change.

Other roles reuse this mechanism instead of rebooting themselves: they drop a request file and let this role reboot the host once, at the window. The system_update role works this way.

Available in the next LFOps release.

How the Role Behaves

  • One reboot window. schedule_reboot__reboot_time__* sets a single time of day at which the actor runs. Steer it per inventory group, for example an earlier window for infrastructure hosts so they reboot before the rest. Without an explicit value each host is assigned a deterministic minute within 04:00-04:59 (seeded by its hostname), so a fleet does not reboot in lockstep.
  • Reboots are modelled as state. A pending reboot is a file in /run/schedule-reboot/; the file name is a category and its content is included in the notification mail. Several pending reasons coalesce into a single reboot. The spool lives on tmpfs, so it clears on the reboot itself.
  • Producers order themselves before the actor. A role that runs work at the same window (such as a system update) declares its unit Before=schedule-reboot.service (order-only, no Wants=/Requires=). systemd then runs the reboot only after that work finishes; on a window where no producer runs, the actor runs alone and reboots only if a request is pending.
  • An Icinga downtime is set around the reboot. When schedule_reboot__icinga2_api_user_login is set, the actor schedules a short host downtime before rebooting, so the reboot does not raise alerts. Without it, the reboot happens without a downtime.

To request a reboot from a script or by hand:

schedule-reboot <reason> [detail ...]         # request a reboot at the next window
schedule-reboot --now <reason> [detail ...]   # reboot as soon as any running producer finishes

To request a reboot from another role's deployed script, write a file directly:

printf '%s\n' "kernel updated" > /run/schedule-reboot/my_role

Dependent Roles

Any LFOps playbook that installs this role runs these for you. Optional ones can be disabled via the playbook's skip variables.

Tags

schedule_reboot

  • Deploys the schedule-reboot CLI, the do-reboot actor, the systemd timer/service, and the /run/schedule-reboot spool directory.
  • Triggers: none.

schedule_reboot:state

  • Determines whether the schedule-reboot timer is enabled.
  • Triggers: none.

Optional Role Variables

schedule_reboot__enabled

  • Whether the schedule-reboot timer is enabled at boot, analogous to systemctl enable / disable --now. Disabling it stops scheduled reboots; schedule-reboot --now still works.
  • Type: Bool.
  • Default: true

schedule_reboot__icinga2_api_url

  • The URL of the Icinga2 API (usually on the Icinga2 Master). Used to set a downtime for the host and all its services around the reboot.
  • Type: String.
  • Default: 'https://{{ icinga2_agent__icinga2_master_host | d("") }}:{{ icinga2_agent__icinga2_master_port | d(5665) }}'

schedule_reboot__icinga2_api_user_login

  • The Icinga2 API user used to set the downtime around the reboot. When unset, no downtime is scheduled.
  • Type: Dictionary.
  • Default: unset

  • Subkeys:

    • username:

      • Mandatory. Username.
      • Type: String.

    • password:

      • Mandatory. Password.
      • Type: String.

schedule_reboot__icinga2_hostname

  • The hostname of the Icinga2 host on which the downtime should be set.
  • Type: String.
  • Default: '{{ ansible_facts["nodename"] }}'

schedule_reboot__mail_from

  • The email sender account, used as the "from" address for the reboot notification.
  • Type: String.
  • Default: '{{ mailto_root__from }}'

schedule_reboot__mail_recipients

  • A list of email recipients for the reboot notification.
  • Type: List of strings.
  • Default: '{{ mailto_root__to }}'

schedule_reboot__mail_subject_hostname

  • String used as the hostname in the mail subject. You can use $() to call bash code.
  • Type: String.
  • Default: '$(hostname --short)'

schedule_reboot__mail_subject_prefix

  • A prefix shown in front of the hostname in the mail subject. Can be used to separate servers by environment or customer.
  • Type: String.
  • Default: ''

schedule_reboot__on_calendar

  • When the reboot actor runs. It reboots only if a request is pending in /run/schedule-reboot/. Defaults to daily at the reboot window. Have a look at systemd.time(7) for the format.
  • Type: String.
  • Default: '*-*-* {{ schedule_reboot__reboot_time__combined_var }}'

schedule_reboot__reboot_grace_period

  • The number of seconds to wait after sending the reboot notification before the host actually reboots. This gives the notification mail time to leave the local mail queue (which is persistent, so the mail is never lost, but otherwise the heads-up can arrive after the host is already back). The host keeps serving during the wait. Set to 0 to reboot immediately.
  • Type: Integer.
  • Default: 60

schedule_reboot__reboot_time__host_var / schedule_reboot__reboot_time__group_var

  • The reboot window: the time of day at which the actor (and the producers ordered before it) run. Steer it per inventory group. Have a look at systemd.time(7) for the format.
  • Type: String.
  • Default: a deterministic per-host minute within 04:00-04:59, staggered by hostname so a fleet does not reboot in lockstep. Pin a fixed value to override, e.g. '04:00'.

schedule_reboot__rocketchat_msg_suffix

  • A suffix to the Rocket.Chat notification. This can be used to mention other users.
  • Type: String.
  • Default: ''

schedule_reboot__rocketchat_url

  • The URL to a Rocket.Chat server to send the reboot notification to.
  • Type: String.
  • Default: unset

Example:

# optional
schedule_reboot__enabled: true
schedule_reboot__icinga2_api_url: 'https://icinga.example.com:5665'
schedule_reboot__icinga2_api_user_login:
  username: 'downtime-user'
  password: 'linuxfabrik'
schedule_reboot__icinga2_hostname: 'myhost.example.com'
schedule_reboot__mail_from: 'noreply@example.com'
schedule_reboot__mail_recipients:
  - 'info@example.com'
  - 'support@example.com'
schedule_reboot__mail_subject_prefix: '001-'
schedule_reboot__reboot_grace_period: 60
schedule_reboot__reboot_time__group_var: '19:00'
schedule_reboot__rocketchat_msg_suffix: '@administrator'
schedule_reboot__rocketchat_url: 'https://chat.example.com/hooks/abcd1234'

License

The Unlicense

Author Information

Linuxfabrik GmbH, Zurich