Agent Daemon Lifecycle

Enable

sudo systemctl enable --now opensvc-server

🛈 Newly installed daemons are not enabled by default.

Boot

om daemon start

• Executed on server boot.
• After reaching the multi-user target.

Side Effects:

• HA services in down state start a local instance.
• Standby resources of all services are started.

🛈 Administrators can prevent these side effects on boot setting the osvc.freeze option in the kernel boot command line.

Shutdown

om daemon shutdown

• Executed on server shutdown.
• The daemon drains all service instances running on the node.
• The peer nodes are free to takeover a HA service as soon as its local instance is drained.

Stop

om daemon stop

• Announces a maintenance period.
• The service instances running on the node are not stopped.
• Peer nodes wait for node.maintenance_grace_period before taking over, expecting the daemon to restart.

🛈 The mainteance period ends as soon as the daemon restarts.

Restart

om daemon restart

A restart is a simple stop-start sequence:

• Maintenance period is announced
• Peer nodes wait for the daemon to restart without taking over.

Run

om daemon run

• Runs a daemon in foreground
• Logs are printed on the console
• Stacks are printed on the console

🛈 Useful for debugging.

Watchdog

• The daemon sends a periodic probe to systemd.
• If the daemon hangs, the probe flow stops, and systemd kill-restart the daemon.

🛈 The daemon event bus hangs are detected internally and cause the watchdog probe flow to stop.