Docker
Package it once, run it anywhere, the same way every time
What it is
About Docker
Docker solves the classic 'works on my machine' problem by bundling an application with everything it needs to run into a lightweight, portable container. It underpins modern CI/CD pipelines, microservices architectures, and cloud deployment workflows, and is one of the most fundamental tools in a modern developer's or DevOps engineer's toolkit.
What you can do with it
Capabilities
Package an application and its dependencies into a container image
Run consistent environments across dev, test and production
Orchestrate multi-container applications with Docker Compose
Integrate containerised builds into CI/CD pipelines
Deploy containers to cloud platforms or Kubernetes clusters
How to learn it
Learning Resources
Docker's official 'Get Started' documentation
freeCodeCamp's Docker courses on YouTube
Docker Labs / Play with Docker for hands-on browser practice
Practise by containerising a small personal project end-to-end
Pro Tip
Write a proper .dockerignore file from the start — without it, builds silently balloon in size and slow down as you copy in node_modules, .git and other junk you never intended to ship.
Skills that use this tool
Roles that use this tool