30 posts tagged with "Docker"

Anyone can write a Dockerfile that works. FROM ubuntu, RUN apt-get install everything, COPY . ., done. It builds. It runs. And it is a 1.8 GB security nightmare that takes 10 minutes to deploy. Here are 12 rules that separate a working Dockerfile from a production-ready one.

You have a web app that needs Postgres, Redis, and Nginx. Running four separate docker run commands with all their flags is painful. Forgetting one flag breaks everything. Docker Compose lets you define your entire application stack in a single YAML file and manage it with one command.

Two containers are running on the same machine. One is your API server, the other is your database. They need to talk to each other. But how? They are isolated processes — they do not share localhost. Understanding Docker networking is the difference between containers that communicate effortlessly and hours of debugging "connection refused" errors.

You spin up a Postgres container, create tables, load data, and everything works. Then you run docker rm and all your data vanishes. This is not a bug — it is by design. Containers are ephemeral. But your data should not be.

You ran docker build and it finished in 0.2 seconds. Then you changed one line of code and suddenly it takes 4 minutes. What happened? The answer lies in how Docker images are built — layer by layer — and understanding this will save you hours of wasted build time.

Docker has revolutionized how we build, ship, and run applications. This practical guide will get you started with Docker containers and help you understand why they're essential for modern development.