Docker Save to TGZ

Docker is a powerful tool for running applications in containers. With Docker, you can easily package an application along with its dependencies into a container image and deploy it to any Docker-enabled host. However, there may be scenarios where you need to save the Docker image as a file for offline storage or distribution. This is where the docker save command comes in handy.

Introduction to Docker Save

The docker save command allows you to save one or more Docker images to a TAR archive. The resulting TAR archive can be loaded into Docker later using the docker load command. The syntax for the docker save command is as follows:

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

The OPTIONS parameter allows you to specify various options for the command, such as the output format or compression algorithm. The IMAGE parameter is a list of one or more Docker image names or IDs that you want to save.

Saving Docker Image to TGZ

To save a Docker image to a TGZ archive, you can use the -o option to specify an output file and the IMAGE parameter to specify the name or ID of the image. For example, to save the official Alpine Linux image to a file called alpine.tar.gz, you can run the following command:

docker save -o alpine.tar.gz alpine:latest

This creates a TGZ archive called alpine.tar.gz in the current directory that contains the Alpine Linux image.

Compression options

By default, Docker saves the image using the gzip compression algorithm. However, you can choose a different compression algorithm using the --compression option. Supported compression algorithms include gzip, bzip2, and zstd. For example, to save the Alpine Linux image using the bzip2 compression algorithm, you can run the following command:

docker save --compression=bzip2 -o alpine.tar.bz2 alpine:latest

This creates a BZIP2 archive called alpine.tar.bz2 in the current directory that contains the Alpine Linux image.

Conclusion

The docker save command is a useful tool for saving Docker images to a file for offline storage or distribution. By using the -o option and choosing an appropriate compression algorithm, you can save Docker images in a variety of formats that are easy to transfer and use later.