Docker Basics, Commands, and Key Concepts

Jan 11. 2022

Docker #

Image #

• A template that can be used to create container services.
• Images are immutable and consist of multiple layers.
• Commonly used base images include ubuntu, alpine, and node.

Container #

• Independently runs one or a group of applications, created from an image.
• A simplified Linux system.
• Containers are lightweight and portable, making them ideal for microservices.

Repository #

• A place to store images.
• Divided into public and private repositories.
• Popular public repositories include Docker Hub and GitHub Container Registry.

Underlying Principles #

How It Works #

• A Client-Server structured system, where Docker’s daemon runs on the host.
• DockerServer receives commands from Docker-Client.
• Docker uses namespaces for isolation and cgroups for resource management.

Key Components #

• Docker Daemon: Runs on the host machine and manages Docker objects.
• Docker CLI: A command-line interface to interact with the Docker Daemon.
• Docker Compose: A tool for defining and running multi-container applications.

Commands #

Container #

docker container my_commandcreate — Create a container from an image. start — Start an existing container. run — Create and start a new container. ls — List running containers. inspect — View detailed information about a container. logs — Print logs. stop — Gracefully stop a running container. kill — Abruptly stop the main process in a container. rm — Remove a stopped container. exec — Run a command inside a running container. cp — Copy files or directories between a container and the host.

Image #

• Use docker image my_commandbuild — Build an image. push — Push an image to a remote registry. pull — Download an image from a remote registry. ls — List images. history — View intermediate image information. inspect — View detailed information about an image, including layers. rm — Remove an image. tag — Tag an image for easier reference.

Network #

• Use docker network my_commandcreate — Create a new network. ls — List all networks. inspect — View detailed information about a network. rm — Remove a network. connect — Connect a container to a network. disconnect — Disconnect a container from a network.

Docker Syntax