Scribbles for my memory

A machine can have normal network connectivity while GitHub Actions sees its self-hosted runner as offline. The runner listener is a separate process, and GitHub may delete a registration after it has been disconnected for a long time. The local .runner file and systemd unit can still remain, which makes the failure easy to miss.

Make ordinary crashes and reboots self-healing with a systemd drop-in:

[Unit]
StartLimitIntervalSec=0

[Service]
Restart=always
RestartSec=10s

Then reload systemd and restart the runner. Check both systemctl is-active locally and the runner status in GitHub. If the log says the registration was deleted or asks you to re-configure, a restart is not enough: obtain a fresh registration token and run config.sh --replace before enabling the service again.