Docker-Hub

A custom image that only exists on your laptop is not shipped; it is a local experiment. The moment a teammate or a server needs to run it, the image has to live in a registry. Docker Hub is the one most people start with, and the push workflow is the same shape you will later use against Azure Container Registry or Amazon ECR, so it is worth doing once by hand before automating it. This post walks through that manual path with a small nginx-based image.

In the previous article I built a custom nginx image and pushed it to Docker Hub by hand: build, tag, login, push. That works exactly once. The second time you forget the tag, the third time a teammate pushes from a laptop with a stale base image, and soon nobody can say which commit produced the image running in production. The fix is boring and reliable: let GitHub Actions do the build and push on every commit to master.