How to check whether docker is using domestic or mirror

Docker is an open source application containerization platform often used to package, ship and run applications. Normally, Docker downloads images faster on international networks, but sometimes due to network problems, we need to use domestic images. So, how to check whether Docker is using domestic or mirroring? This article will introduce you to the specific steps.

1. Check the installed Docker version

First check the installed Docker version. The specific command is as follows:

docker --version

If Docker has been installed, the system will return Docker version information, as shown in the figure below:

2. Check the currently used Docker Registry

Docker Registry is where Docker stores images. It can be the official Docker Hub or a domestic Registry. To view the currently used Docker Registry, you can use the following command:

docker info

After executing the command, the system will return detailed Docker information, including a paragraph It is the address of the currently used Docker Registry, as shown in the following figure:

As can be seen from the above information, the currently used Docker Registry is Alibaba Cloud's Registry.

3. View the currently used Docker images

Execute the following command to view the list of Docker images installed in the current system:

docker images

After executing this command, the system will return all installed Docker image information, as shown in the following figure:

As can be seen from the above figure, the downloaded Neo4j and Hello-World images are official images, and no domestic images are used.

If we want to use domestic images, we can modify the default Docker Registry. The specific method is as follows:

4. Modify the Docker configuration file

In the Linux system, the currently logged in The user's Docker configuration file is stored in the ~/.docker/config.json file. Therefore, modifying this file can modify Docker's default Registry. The specific method is as follows:

1. Enter the .config folder

Enter the following command in the terminal to enter the .config folder of the current user:

cd ~/.docker

2. Open the config.json file

Enter the following command to open the config.json file:

vim config.json

After entering the vim editor, press the "i" key to enter the editing mode, find the "registry-mirrors" configuration item, and change its content to the address of the local Registry. For example, change the Registry address to "https://registry.docker-cn.com", and the edited config.json file is as shown below:

Editing completed Finally, press the "ESC" key to return to the command mode, then enter the ":wq" command to save and exit the editor.

3. Restart the Docker service

Enter the following command to restart the Docker service:

systemctl restart docker

After the restart is complete, use the docker images command again to view the downloaded image. You can see that Docker has used the domestic image.

Summary

The above is the method to check whether Docker is using a domestic image. You can determine whether a domestic image is used by checking the installed Docker version, the currently used Docker Registry, and the downloaded Docker image list. If you want to switch to a domestic image, you only need to modify the Docker configuration file.

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