Container-Init (PID 1)

sysg init runs systemg as a container's PID 1 on linux-gnu and linux-musl (Alpine is a first-class target), replacing tini/s6/supervisord combinations with one supervisor that already owns lifecycle, logs, and diagnostics.

ENTRYPOINT ["sysg", "init", "--config", "/etc/systemg/systemg.yaml"]

sysg init requires that the process actually is PID 1 and implies system mode. It boots the manifest, reaps adopted orphans, handles shutdown signals, and exits with the teardown verdict.

What PID 1 changes

PID 1 inherits every orphaned process in the container and must reap them; default signal dispositions differ; shutdown means tearing down every service in reverse dependency order and exiting with a meaningful status. All wait statuses route through a centralized broker, so an adopted orphan's exit is never mistaken for a managed service's.

Diagnostics

• SG0711 — container-init unsupported on this platform (e.g. macOS)
• SG0712 — PID 1 prerequisites missing (e.g. /proc not mounted)
• SG0713 — shutdown incomplete: services survived reverse-order teardown
• SG0714 — live supervisor upgrade refused in container-init mode

Known constraint

Live supervisor upgrade is forbidden in container-init mode: a failed exec in PID 1 kills the container and everything in it. Upgrade the image instead.