Docker Image vs Container: A Practical Guide
A Docker image is like a recipe or template for your application. It contains your app’s code and everything needed to run it (dependencies, libraries, settings). It doesn't run by itself, it is just a snapshot, ready to be used.
A Docker container is a running instance of a Docker image. When you start an image, you get a container—it's like a fully functional mini-computer isolated from your system. Containers can be started, stopped, or moved anywhere easily.
Think of images as blueprints and containers as the houses built from those blueprints.
Quick Definitions
| Term | What It Is | Real-World Analogy |
|---|---|---|
| Docker Image | Read-only snapshot with code, libraries & config | Architectural blueprint |
| Docker Container | Live, writable instance of an image running a process | Finished house you can live in |
Key Takeaways
- Images = static, versionable, shareable files.
- Containers = runtime instances with their own filesystem & PID space.
- You can launch multiple containers from a single image—just like building many identical houses from one set of plans.