In `scripts/s6/docker/run`, `s6-notifyoncheck` runs without the `-d` flag:
```bash
exec s6-notifyoncheck -n 0 dockerd-entrypoint.sh
```
Without `-d`, `s6-notifyoncheck` performs a single fork to execute the background checking process. The parent immediately replaces itself via `exec` with `dockerd-entrypoint.sh` (which calls `exec rootlesskit` on `dind-rootless`).
Because only a single fork occurred, the background checking child remains parented to `rootlesskit`. When the check passes and the process terminates:
1. `rootlesskit` did not spawn this process and never reaps it via `waitpid()`.
2. Under standard Linux process semantics, `s6-svscan` (PID 1) cannot adopt or reap the child because its parent (`rootlesskit`) is still running.
3. The terminated process remains as a permanent zombie (`[s6-notifyoncheck] <defunct>`) for the container's entire lifespan.
Adding `-d` instructs `s6-notifyoncheck` to double-fork, detaching the background check so it is immediately adopted by `s6-svscan` (PID 1) and cleanly reaped upon exit.
---------
Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1364
Reviewed-by: silverwind <[email protected]>
Co-authored-by: adamaru <[email protected]>
Fixes https://gitea.com/gitea/runner/issues/1263
- Wait for dockerd without a check limit. s6 readiness gave up after 7 checks, so the runner never started on slow hosts, also seen in https://gitea.com/gitea/runner/issues/712, https://gitea.com/gitea/runner/issues/652 and https://gitea.com/gitea/runner/issues/758.
- Let the runner run the docker service's readiness check itself instead of reading s6 status, which can be missing at startup or stale after an unclean stop.
- Exit the container with the first failing service's exit code instead of always 0, so `restart: on-failure` works. A requested stop still exits 0.
- Stop the runner before dockerd, so running jobs can finish within `shutdown_timeout`. The stop grace period has to cover that drain.
- Check the supervision exit codes in `make test-dind`.
---------
Co-authored-by: bircni <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1265
Reviewed-by: bircni <[email protected]>
- `basic`: Only the runner process in the container; users need to mount the Docker socket to it.
- `dind`: A Docker daemon will be started in the container with the root user.
- `dind-rootless`: A Docker daemon will be started in the container with a rootless user.
Use s6 instead of supervisord to start processes.
Reviewed-on: https://gitea.com/gitea/act_runner/pulls/619
Reviewed-by: Zettat123 <[email protected]>
Reviewed-by: Lunny Xiao <[email protected]>
Co-authored-by: Jason Song <[email protected]>
Co-committed-by: Jason Song <[email protected]>
adamaruandsilverwind
Jason Song