Detailed explanation of Docker's most commonly used image commands and container commands

This article lists the most commonly used image commands and container commands in the use of Docker, and teaches you how to operate container data volumes and back up container data. After you have mastered these commands, you can practice some simple application deployment and learn more about Docker image building, backup, recovery, migration, image repository, network, cluster, and more.

Mirror related commands

Official documentation: https://docs.docker.com/reference/

View Mirror

[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest bf756fb1ae65 7 months ago 13.3kB

• REPOSITORY : The name of the image in the repository, referred to as the image name in this article
• TAG : image tag
• IMAGE ID : Image ID
• CREATED : The date the image was created (not the date the image was obtained)
• SIZE : Image size

These images are stored in the /var/lib/docker directory of the Docker host.

Search Mirror

If you need to find the required image from the network, you can search it with the following command.

docker search image name 

• NAME : image name
• DESCRIPTION : Image description
• STARS : User ratings, reflecting the popularity of an image
• OFFICIAL : Whether it is an official build
• AUTOMATED : Automatically built, indicating that the image is created by the Docker Hub automatic build process.

Pull the image

Pulling an image means downloading the image from the central repository to the local computer.

docker pull image name

If I want to pull the centos image to the local computer, if I do not declare the tag image label information, the latest version will be pulled by default. You can also search for the image through: https://hub.docker.com/ to view the supported tag information.

By viewing the tag information, if we want to download the centos7 image.

docker pull centos:7

Deleting an image

Delete an image by its ID.

# Delete a single image docker rmi image ID
# Delete multiple images docker rmi image ID image ID image ID

docker images -q can query the IDs of all images, and all images can be deleted by combining commands.

docker rmi `docker images -q`

Note: If a container is created from an image, the image cannot be deleted.

Solution: Delete the container in the image first, and then delete the image.

Container related commands

View Container

View the running containers.

[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

• CONTAINER ID : Container ID
• IMAGE : the image to which it belongs
• COMMAND :
• CREATED : creation time
• STATUS : container status
• PORTS ：Port
• NAMES : container name

View stopped containers.

docker ps -f status=exited

View all containers (both running and stopped).

docker ps -a

View the last running container.

docker ps -l

Creating and starting a container

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

• -i : means running the container;
• -t : Indicates that the container will enter its command line after it starts. After adding these two parameters, you can log in to the container after it is created. That is, allocate a pseudo terminal;
• --name : Name the created container;
• -v : indicates the directory mapping relationship (the former is the host directory, and the latter is the directory mapped to the host). You can use multiple -v to map multiple directories or files. Note: It is best to do directory mapping, make changes on the host machine, and then share it to the container;
• -d : Add the -d parameter after run to create a guarded container and run it in the background (you will not automatically log in to the container after the container is created. If you only add the -i -t parameters, you will automatically enter the container after the container is created);
• -p : indicates port mapping. The former is the host port, and the latter is the mapping port in the container. You can use multiple -p options to map multiple ports.
• -P : Randomly use the available ports on the host to map to the ports exposed in the container.

Create and enter the container

The following command line means to create a container BB through the image AA, run the container and enter the container's /bin/bash .

docker run -it --name container name image name: tag /bin/bash

Note: A Docker container must have a foreground process to run. If there is no foreground process executing, the container is considered to be in an idle state and will automatically exit.

Exit the current container

exit

Creating containers in a guarded manner

docker run -di --name container name image name: tag

Login guard container mode

docker exec -it container name | container ID /bin/bash

Stopping and starting containers

# Stop the container docker stop container name | container ID
# Start the container docker start container name | container ID

File Copy

If we need to copy files into the container, we can use the cp command.

docker cp The file or directory to be copied Container name: container directory

It is also possible to copy files out of the container.

docker cp container name: the file or directory to be copied in the container directory

Directory mount (container data volume operation)

When creating a container, we can map the host directory to the directory in the container, so that we can affect the container by modifying the files in a directory of the host. This operation is bidirectionally bound, which means that the operation in the container will also affect the host, realizing the backup function.

However, when the container is deleted, the contents of the host machine will not be deleted because the underlying layer is implemented through copying. If multiple containers mount the same directory and one of the containers is deleted, the contents of other containers will not be affected. Similarly, the underlying layer is implemented by copying.

However, when the container is deleted, the contents of the host are not deleted. If multiple containers mount the same directory and one of the containers is deleted, the contents of the other containers will not be affected.

The data volume between the container and the host is a reference relationship. The data volume is mounted from the outside to the container, so it can exist independently from the container life cycle. Precisely because the life cycle of the data volume is not the same as the life cycle of the container, the data volume will not be affected after the container exits or is deleted. The life cycle of the data volume will continue until no container uses it.

When creating a container, add the -v parameter in the format of宿主機目錄:容器目錄, for example:

docker run -di -v /mydata/docker_centos/data:/usr/local/data --name centos7-01 centos:7
# Multiple directories mount docker run -di -v /host directory:/container directory -v /host directory 2:/container directory 2 image name

The directory mounting operation may prompt that insufficient permissions are required. This is because the security module SELinux in CentOS7 has disabled permissions. When running docker, add permissions to the container by using --privileged=true to solve the problem of no permissions on the mounted directory.

Anonymous Mount

Anonymous mounting only requires writing to the container directory, and the corresponding directory outside the container will be generated in /var/lib/docker/volume .

# Anonymous mount docker run -di -v /usr/local/data --name centos7-02 centos:7
# View volume data volume information docker volume ls 

Named mount

Named mounting is to give the data volume a name, and the corresponding directory outside the container will be generated in /var/lib/docker/volume .

# Anonymous mount docker run -di -v docker_centos_data:/usr/local/data --name centos7-03 centos:7
# View volume data volume information docker volume ls

Specify directory to mount

The method explained to you at the beginning is to mount the specified directory. This method of mounting will not generate content in the /var/lib/docker/volume directory.

docker run -di -v /mydata/docker_centos/data:/usr/local/data --name centos7-01 centos:7
# Multiple directories mount docker run -di -v /host directory:/container directory -v /host directory 2:/container directory 2 image name

View directory mount relationships

You can view the directory address of the host machine corresponding to the data volume by docker volume inspect 數據卷名稱.

[root@localhost ~]# docker volume inspect docker_centos_data
[
 {
 "CreatedAt": "2020-08-13T20:19:51+08:00",
 "Driver": "local",
 "Labels": null,
 "Mountpoint": "/var/lib/docker/volumes/docker_centos_data/_data",
 "Name": "docker_centos_data",
 "Options": null,
 "Scope": "local"
 }
]

You can view detailed data mount information by docker inspect 容器ID或名稱and finding Mounts in the returned JSON node.

Read-only/Read-write

# Read-only. The data management of the container can only be achieved by modifying the host content.
docker run -it -v /host directory:/container directory:ro image name# Read-write, default. The host and the container can operate data in both directions.
docker run -it -v /host directory:/container directory:rw image name

volumes-from (inheritance)

# Container centos7-01 specifies the directory to mount docker run -di -v /mydata/docker_centos/data:/usr/local/data --name centos7-01 centos:7
# Containers centos7-04 and centos7-05 are equivalent to inheriting the mount directory of the centos7-01 container docker run -di --volumes-from centos7-01 --name centos7-04 centos:7
docker run -di --volumes-from centos7-01 --name centos7-05 centos:7

View the container IP address

We can view the container's meta information with the following command.

docker inspect container name | container ID

You can also directly execute the following command to output the IP address directly.

docker inspect --format='{{.NetworkSettings.IPAddress}}' container name | container ID

Deleting a container

# Delete the specified container docker rm container name | container ID
# Delete multiple containers docker rm container name | container ID container name | container ID

I have previously introduced to you the detailed usage of the Docker run command. Friends who are interested can refer to it!

This concludes this article about the most commonly used Docker image commands and container commands. For more relevant Docker image commands and container commands, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope you will support 123WORDPRESS.COM in the future!