About dockerfile generator
A Dockerfile describes how to build a container image for your app. Good Dockerfiles are small, fast to build and safe.
Best practices
- Use a small, official base image with a specific version tag.
- Copy dependency files first and install, so Docker can cache that layer.
- Use multi-stage builds to keep build tools out of the final image.
- Run as a non-root user.
A worked example
For a Node.js app: start from node:20-alpine, set the working directory, copy package.json and run npm ci before copying the rest, so installs are cached. Expose port 3000, switch to the non-root node user and set CMD ["node", "server.js"]. A multi-stage build keeps compilers and dev packages out of the final image.
Checks before shipping
- Pin base image versions instead of using latest.
- Add a .dockerignore so the image stays small.
- Scan the image for known vulnerabilities.
