microinit

Lightweight PID 1 init system and service supervisor designed for BigFred OS. Works in embedded systems based on Linux as well as in containers.

In supervise mode it can also act as a supervisord replacement: the same process watches a declarative JSON service list, restarts daemons, and exposes start/stop/logs over a Unix socket — without early-boot, getty, or console TTYs.

Features

• Declarative services in /data/etc/microinit.json (override root with DATA_DIR)
• Drop-ins under $DATA_DIR/etc/microinit.d/services/**/*.json (lexicographic later-wins)
• inotify hot-reload of JSON config (no polling)
• microinit supervise — container / host supervisor (supervisord-like)
• Thread-per-service supervision with optional restart + backoff
• Unix socket IPC (start / stop / restart / enable / disable / list / logs)
• Optional OpenTelemetry metrics (on by default; disable with --no-default-features) → Grafana Alloy when openTelemetry.enable is true
• Mixed service logs on a dedicated TTY (default /dev/tty2); init logs on /dev/tty3
• Early boot via /etc/microinit/early-boot.sh (or $DATA_DIR/etc/microinit/early-boot.sh); embedded portable script if neither exists

Build

export RUSTUP_TOOLCHAIN=stable
make build
make release
cargo build --release                        # includes OpenTelemetry exporter
cargo build --release --no-default-features  # without OpenTelemetry
make release-musl   # aarch64-unknown-linux-musl static
make test
make man

Tests

cargo test
cargo test --no-default-features

Local test harness

./examples/local-test/run.sh

Uses examples/local-test/data as DATA_DIR, skips early-boot, and opens two xterms for service / init logs.

OpenTelemetry → Grafana Alloy

Default builds include the OTLP exporter. Enable it at runtime in config:

"openTelemetry": {
  "enable": true,
  "endpoint": "http://127.0.0.1:4318",
  "protocol": "http",
  "serviceName": "microinit",
  "exportIntervalSecs": 15
}

See grafana/alloy/microinit.alloy and grafana/dashboards/microinit.json.

CI / distribution

• ORAS (arm64 + early-boot): ghcr.io/dcc-bigfred/microinit-linux-arm64
• Container (distroless multiarch, supervise): ghcr.io/dcc-bigfred/microinit

docker run --rm -v "$PWD/data:/data" ghcr.io/dcc-bigfred/microinit:main
# ENTRYPOINT /microinit  CMD supervise
oras pull ghcr.io/dcc-bigfred/microinit-linux-arm64:latest-release -o ./out

CLI

microinit [--socket PATH] init …
microinit [--socket PATH] supervise [--config PATH] [--log-to-files]
microinit start|stop|restart|enable|disable <name>
microinit start --force <name>   # ignore unmet dependsOn
microinit list
microinit logs [name] [--follow] [--lines N]

See man/man8/microinit.8.mdoc and man/man5/microinit.json.5.mdoc.

License

MIT

Documentation

See docs/README.md for the full index.

• Operator guide — manage services, write config, dependencies, boot
• Control socket API — Unix socket protocol for integrations
• Architecture — design overview (init / supervise, reload, OTel)