How to save container settings in Docker

Docker is an open source application containerization platform that manages applications and services by creating, deploying, and running containers. Using Docker simplifies application deployment, allowing developers to iterate faster and test and deploy in different environments more easily. In Docker, we can save container settings for next time. Next, this article will introduce how to save container settings in Docker.

Container life cycle

In Docker, the life cycle of a container can be summarized into the following steps:

1. Create a container: Create a Docker through a Docker image Container;
2. Start the container: run an already created Docker container;
3. Enter the container: Enter the running Docker container through the command line or other methods;
4. Modify the container: Make modifications inside the container, such as installing software, modifying configurations, etc.;
5. Stop container: stop the running Docker container;
6. Delete container: delete the stopped Docker container.

In the life cycle of the container, it is often necessary to set up the container. For example, configure the network, storage, etc. settings of the container. Next, we’ll dive into how to save container settings in Docker.

Saving and loading containers

Docker provides the commit and save commands to save container settings for next use.

commit command

commit command is used to save the container as a new image. The specific usage is as follows:

docker commit [OPTIONS] CONTAINER [REPOSITORY[:TAG]]

Among them, OPTIONS can specify some parameters, such as the name of the container, the description of the container, etc. CONTAINER is the ID of the container to be saved. You can use the docker ps -a command to find the container ID. REPOSITORY: TAG is the name and tag of the new image, which can be customized.

For example, we need to save a container named mycontainer as a myimage image, execute the following command:

docker commit mycontainer myimage

After the execution is completed, we You can use the docker images command to view saved images. If the myimage image does not exist, the output is empty.

save command

If we need to share the saved image with others, we can use the save command to package the image into a tar file for easy sharing. The specific usage is as follows:

docker save [OPTIONS] IMAGE [IMAGE...]

Among them, OPTIONS can specify some parameters. IMAGE is the name of the image to be saved. Multiple image names can be packaged together.

For example, we need to package and save the myimage image as a myimage.tar file, execute the following command:

docker save -o myimage.tar myimage

After the execution is completed, we You can use the ls command to check whether the myimage.tar file exists in the current directory.

load command

If we need to load the shared image onto other machines, we can use the load command to restore the tar file to an image. The specific usage is as follows:

docker load [OPTIONS] < myimage.tar

For example, we need to restore the myimage.tar file to the myimage mirror, execute the following command:

docker load -i myimage.tar

Execute After completion, we can use the docker images command to view the loaded image.

Summary

In Docker, we can use the commit command and the save command to save the container settings. Among them, the commit command can save the container as a new image, and the save command can package the image into a tar file. If you need to load the shared image onto other machines, we can use the load command to restore the tar file to an image. Mastering these commands will allow us to better put Docker into practice and better back up and share our container setup.

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