42 posts tagged with "Containers"

You are building Docker images on your laptop and pushing them to production with docker push. It works until it does not — someone forgets to run tests, pushes a debug build, or tags latest over a stable release. CI/CD pipelines eliminate these human errors by making every build reproducible, tested, and traceable to a specific commit.

You hard-coded the database password in the Dockerfile. It worked in development. Then someone pushed the image to a public registry. Now your database password is on the internet forever, baked into an immutable image layer that docker history will happily reveal to anyone. Environment variables done right prevent this entire class of mistakes.

Your app works locally, but the moment you deploy to Kubernetes, the frontend cannot reach the backend. You run curl from inside a pod and get nothing. DNS resolution fails. Network policies silently drop traffic. Kubernetes networking is powerful, but if you do not understand the fundamentals, you will spend hours debugging what should be a five-minute fix.

Your container is "running." The process has PID 1, Docker says status is Up 47 minutes, and everything looks fine. Except the application inside crashed 20 minutes ago, the event loop is deadlocked, or the database connection pool is exhausted. Traffic keeps flowing in. Users keep getting 502 errors. Docker has no idea anything is wrong because "running" and "healthy" are not the same thing.

You've Dockerized your app, and it runs perfectly on your laptop. Now you need to run it in production — with load balancing, auto scaling, rolling deployments, and health checks. AWS gives you three ways to do this: ECS, Fargate, and EKS. Choosing wrong means either over-engineering a simple app or under-engineering a complex one. Let's break down exactly when to use each.

A container is not a security boundary. It shares the host kernel, and a misconfigured container running as root with all capabilities is one exploit away from full host compromise. The good news is that Docker gives you layers of defense — most people just never enable them.