Dumb-init for containers

dumb-init is a minimal PID 1 wrapper for Linux containers. It forwards signals to the child process and reaps zombie processes. We adopt it when the main process is not designed to run as init (most app images).

Blurb

dumb-init runs as PID 1, acting like a simple init system. It launches a single process and then proxies all received signals to a session rooted at that child process.

Summary

Problem: Docker and Kubernetes start your app as PID 1. Without a proper init, SIGTERM handling and zombie reaping break. Shell wrappers as PID 1 add their own signal quirks.

When to use: production images where the entrypoint is a single binary or script; you need reliable graceful shutdown on docker stop / pod termination.

When to skip: distroless images that already ship a correct init; images using tini or Kubernetes shareProcessNamespace patterns you have standardized on.

Usage sketch: install the static binary in the image and set ENTRYPOINT ["/usr/bin/dumb-init", "--"] with CMD for the app.