Introduction to Docker, including 3 basic concepts#
1.1 Docker consists mainly of images and containers#
Image: A Docker image is like a template, similar to a file system
Container: Containers are created using images. Images and containers are like classes and instances in object-oriented programming. Containers can be created, started, stopped, and deleted, etc.
Repository: A repository is a place to store images, divided into private repositories and public repositories. Similar to Git
1.2 Docker's operating principle#
Docker is a Client-Server system, with the Docker daemon running on the host and accessed from the client through a socket. When the Docker server receives instructions from the Docker client, it executes the command.
I. Installing Docker on Mac#
1.1 Homebrew's cask should support Docker for Mac, so you can directly install it with brew cask install docker
1.2 You can also download it directly from the official website: https://download.docker.com/mac/stable/Docker.dmg
1.3 Docker's reference documentation: https://docs.docker.com
1.4 Docker Hub for finding image sources: https://hub.docker.com
II. Using Docker#
1.1 Check the version#
docker --version
docker-compose --version
docker-machine --version
1.2 Check Docker system information, including the number of images and containers, etc.#
docker info
1.3 Help command#
docker help
1.4 Check CPU usage#
docker stats
III. Basic Docker commands#
Commands related to images:
1.1 Check available versions of an image (using nginx as an example)#
docker search nginx
1.2 Download an image#
docker pull nginx:latest #(followed by the image version)
1.3 Run an nginx server#
docker run -d -p 81:80 --name webserver nginx
Options:
#--name webserver: Container name for distinguishing containers
#-p 81:80: Port mapping, mapping the local port 81 to the internal port 80 of the container
#-v ~/nginx/html:/usr/share/nginx/html: Data volume mounting ro/rw, mounting the directory in the host project to the directory in the container. By default, rw can only be changed outside the host, and cannot be changed inside the container.
#-d: Run the container in the background
#-it: Run interactively, enter the container to view the content
#-P: Random port
#-e: Environment configuration settings
Note: To start in the background, there must be a foreground process. If Docker does not find an application, it will automatically stop.
Key point: Data volume mounting can achieve data sharing, container persistence, and synchronization operations. You can use docker volume to view the status of volumes, and use volumes-from to achieve data sharing between multiple containers.
1.4 Stop the nginx service#
docker stop webserver(container ID)
1.5 Delete the nginx service#
docker rm webserver
1.6 Start/restart the nginx service#
docker start/restart webserver
1.7 List all images (the list includes repository name, tag, image ID, creation time, and space occupied)#
docker images ls
Explanation:
REPOSITORY: Repository source of the image
TAG: Tag of the image
IMAGE ID: ID of the image
CREATED: Creation time of the image
SIZE: Size of the image
Options:
-a: List all images
-q: Only display the image ID
Note: The image ID is a unique identifier. One image can have multiple tags.
1.8 Check the space occupied by images, containers, and volumes#
docker system df
1.9 Delete an image#
Specify the image:
docker rmi [image name/image short ID/image long ID/image digest]
Multiple images:
docker rmi image ID image ID image ID
All images:
docker rmi $(docker images -aq)
2.0 Delete all images with the repository name "redis" using the docker images ls command#
docker rmi $(docker images ls -q redis)
2.1 View the running history of an image#
docker history image ID
Commands related to containers
1.1 List containers#
docker ps
Options:
-a: Show all containers, including those not running
-l: Show the most recently created container
-n: List the n most recently created containers
-q: Only display the container ID
1.2 Enter a container#
docker exec -it [container name] /bin/bash
docker attach container ID
Difference: docker exec opens a new terminal after entering the container, allowing operations inside; docker attach enters the terminal currently running in the container without starting a new process.
1.3 Exit a container#
Stop the container and return to the host:
exit
Exit the container without stopping it:
ctrl+p+q
1.4 Delete a container#
Specify the container:
docker rm [container ID]
Multiple containers:
docker rm container ID container ID container ID
All containers:
docker rm $(docker ps -aq)
docker ps -a -q | xargs docker rm
Note: You cannot delete a running container. To delete a running container, you need to add the -f parameter: docker rm -f container ID
1.5 Start/restart a container#
docker start/restart container ID
1.6 Stop/force stop a container#
docker stop/kill container ID
1.7 View container logs#
docker logs -f -t --tail 100 container ID
#--tail must be followed by the number of lines
1.8 View process information in a container#
docker top container ID
1.9 View metadata of a container (important command)#
docker inspect container ID
2.0 Copy data from a container to the host#
docker cp container ID:container path host path
IV. Dockerfile instructions
FROM: Base image, everything starts from here
MAINTAINER: Author of the image, Name <Email>
RUN: Commands to be run during image build
ADD: Step, add content
WORKDIR: Working directory of the image
VOLUME: Mounted directory
EXPOSE: Port configuration
CMD: Specifies the command to run when the container starts. Only the last one will take effect and can be replaced.
ENTRYPOINT: Specifies the command to run when the container starts, additional commands can be appended
ONBUILD: Runs when building an inherited Dockerfile
COPY: Similar to ADD, copies files to the image
ENV: Sets environment variables during the build process