Docker Overview
Docker hit the scene around 2013 and changed everything about how we package applications. Instead of the old “works on my machine” nightmare, Docker lets you bundle your app and all its dependencies into a neat little container that runs the same way everywhere.
Docker didn’t invent containers, but they made them usable by regular developers. Before Docker, working with containers felt like performing surgery with oven mitts on.
What does Docker actually do? It gives you tools to build, run, and share containers. Think of containers as super lightweight, standalone app packages that include everything needed to run your code – from system libraries to configuration files.
Pros of Docker
Docker shines in several ways that made it catch fire in the industry:
First off, the simplicity is a game-changer. I can teach a junior dev Docker basics in an afternoon. Try that with Kubernetes and watch their eyes glaze over.
Docker containers start up in seconds, unlike the painful minutes for traditional VMs. This makes development cycles way faster – change code, rebuild container, test, repeat.
The isolation between containers means your Node app won’t conflict with that weird Python dependency another service needs. Each gets its own little world.
Docker Hub gives you thousands of ready-made images. Need Postgres? One command. Redis? One command. No more spending days configuring databases.
Cons of Docker
Docker isn’t perfect, and its limitations become obvious as you scale:
Docker alone gets messy with lots of containers. I once watched a team with a whiteboard full of sticky notes tracking which container ran where. Not sustainable.
The networking in vanilla Docker is pretty basic. If you need advanced network policies, Docker alone will frustrate you.
When containers die in production (and they will), Docker doesn’t automatically restart them across your infrastructure without additional tooling.
Scaling out means manual work – there’s no built-in load balancing or distribution of containers across multiple servers.