What nobody tells you: container image layers accumulate silently. A Docker image that starts at 800MB becomes 2.1GB over six months of "quick build" commits nobody cleans up. Run docker image prune on a schedule.
Secrets management in Docker is not solved by environment variables. ENV instructions in Dockerfiles expose secrets in image history. Use Docker Secrets or AWS Secrets Manager mounted at runtime.
Container health checks are not optional. Without them, a container that is running but not serving requests appears healthy — the orchestrator keeps sending it traffic.
The fundamentals are straightforward. The production discipline is what separates reliable containerised systems from unreliable ones.
— Dick Bassey | DevDick | 2022