multi-stage builds

Today I learned that recursively changing the owner of a directory tree in a Dockerfile can result in some serious increase in image size. 🚛 The issue You may remember how in a previous post we used a small example to discuss layers and final image size. Well, here’s our example again, slightly modified. # Dockerfile FROM ubuntu WORKDIR /app RUN fallocate -l 100M example RUN chown 33:33 example Given that the base image weighs ~75MB, we could expect the final image to weigh ~175MB (~75 from the base image + ~100 from the big file we generated)....

In previous posts we talked about poetry and Docker images layers and I promised I would write about Docker multi-stage builds, so here we go! Note I will explain the basics of Docker multi-stage builds required to understand the post, but I won’t repeat the documentation (see further reading). ⚙️ Multi-stage builds Basically a multi-stage build allows you to sequentially use multiple images in one Dockerfile and pass data between them....