Docker consists of images, containers, and repositories. Images serve as templates for creating immutable containers, which are lightweight and ideal for microservices. Docker operates on a client-server model, utilizing a daemon for management. Key commands include creating, starting, and managing containers and images, as well as handling networks.
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, andnode.
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.