Docker

Dockerfiles that don't rot, volumes and networks you can explain, and Compose files other people can run. You will shrink a build context, fix permission errors, wire services together with health checks and push an image to a registry. If you skip the checks on ports, secrets and tags, the project runs on your laptop and breaks on the next machine.

Faster builds, safer images, and containers you can run under load without guessing what fails first. You will cut rebuild times with cache mounts and multi-stage builds, run as non-root on a read-only filesystem, set limits and health checks that mean something, keep logs and registry tokens under control, and deploy a new version on one host without dropping requests. Skip this and the containers work fine right up to the day the disk fills, the memory runs out or a deployment drops a customer's request.