Dockerfile FROM: base images, tags, and multi-stage builds

FROM initializes a new build stage and sets the base image.

The FROM instruction defines the base OS image. It is mandatory as the first uncommented instruction in every Dockerfile. All subsequent instructions build on top of the specified image in the form IMAGE:TAG (e.g., debian:wheezy). If the tag is omitted, Docker defaults to latest — always specify a version tag explicitly to avoid surprises.

open_in_new Official docs on the FROM instruction .