How to optimize Docker build cache usage?

Docker layers are cached based on command and file changes — use .dockerignore, group unchanged commands together, COPY only necessary files before RUN instructions, and leverage --cache-from for multi-machine builds. Each layer that doesn't change is skipped during rebuilds.

Look at your FROM instruction. It's pulling a base image that hasn't been tagged in six months, and then you copy your entire source directory into it before installing dependencies — so every minor code change invalidates every subsequent layer in the build cache because of how Docker works (which I

This has been answered at least four times in this thread already, but I'll summarize it since apparently reading the previous posts is too much to ask: order your Dockerfile by layer size and frequency of change — copy dependency files first with a separate RUN step before copying the rest of your source