#dockerfile

DevOps & CI/CD Bug Report

docker run arguments replaced the whole command: CMD vs ENTRYPOINT override rules

John Nguyen · Aug 5, 2026 · 8 min read

Passing --workers 4 to docker run crashed the container with exec: "--workers": executable file not found. Arguments after the image name replace CMD entirely; they do not append. We explain the override rules in Docker, Compose and Kubernetes and the image layout that makes extra flags safe.

DevOps & CI/CD

From a 1.1 GB image to 96 MB: multi-stage Docker builds, slim bases and measuring layers

Isabel Ferreira · Jun 7, 2026 · 6 min read

A Node.js API image had grown to 1.1 GB, slowing every deploy and autoscaling event. Step by step, we measured where the size came from, moved to a multi-stage build, chose a base image deliberately and cleaned the build context, ending at 96 MB, with the trade-offs of each step.

DevOps & CI/CD Bug Report

Docker build reinstalls every dependency on each commit: COPY order and cache busting

Daniel Tran · Oct 15, 2024 · 8 min read

Every push to our FastAPI service spent seven minutes reinstalling the same Python packages. COPY . . ran before pip install, and a missing .dockerignore let .git changes bust the cache. Reordering layers and a cache mount cut builds to 50 seconds.