Fundamental Docker Concepts and Common Commands

Docker enables “build once, run anywhere”, ensuring consistent environments, isolation, and rapid service deployment.

1. After writing code locally, you build an image using the docker build command, with the build rules defined in a Dockerfile.

2. An image is a static, read‑only file; you can differentiate images by applying tags with the docker tag command.

3. Images are stored in a repository; you push them to a repository using docker push, and a repository can hold many images.

4. A registry is the server that hosts repositories; installing a private registry on your own machine lets you run a private image store.

5. To run a service, you pull an image from the registry with docker pull and start a container using docker run; a container is the runtime instance of an image, acting like an isolated lightweight server.

6. Data persistence is handled with volumes; a docker volume mounts host‑machine storage into a container, and a dedicated volume container can share data among multiple containers.

7. You can export an image to a compressed file with docker save and import it back with docker load.

8. Containers can be exported with docker export, producing a snapshot file without history; they can be imported with docker import, which creates a new image rather than a running container.

The article concludes by noting that these basic Docker concepts and commands will be expanded in future posts, including how to use Docker with Node.js.