The “docker load” command is a Docker CLI command used to load Docker images from files or standard input (stdin) into a Docker environment. It allows users to import Docker images that have been previously saved or exported using the “docker save” command.
When using the “docker load” command, users provide the image data as input either from a file or by piping it through standard input. The image data can be in the form of a compressed tarball (with a .tar extension) or a raw image archive.
Here are the main use cases and functionalities of the “docker load” command:
- Loading Images from Files: Users can load Docker images from a saved image file using the “docker load” command followed by the file path. This allows for easy distribution and sharing of Docker images by simply providing the image file to other users or systems.
- Loading Images from Standard Input: The “docker load” command also supports reading image data from standard input (stdin). This allows users to pipe the image data directly into the command, which is useful when working with other tools or scripts that generate the image data dynamically.
- Importing Docker Images: When a Docker image is loaded using “docker load,” it is imported into the local Docker environment and becomes available for use. The imported image retains all its original metadata, layers, and tags, allowing users to run containers based on that image or further modify and extend it as needed.
- Bulk Loading of Images: The “docker load” command supports loading multiple Docker images from a single file. If the input file contains multiple images, all of them will be imported into the Docker environment. This makes it convenient to distribute and load multiple images at once.
It’s important to note that the “docker load” command is used specifically for loading Docker images, not for containers. To load containers, the “docker run” or “docker create” commands are typically used.
docker load Command Examples
1. Load a Docker image from stdin:
# docker load < path/to/image_file.tar
2. Load a Docker image from a specific file:
# docker load --input /path/to/image_file.tar
3. Load a Docker image from a specific file in quiet mode:
# docker load --quiet --input /path/to/image_file.tar
In summary, the "docker load" command is a useful tool for importing Docker images into a Docker environment. Whether loading images from files or standard input, this command allows users to easily distribute, share, and import Docker images into their local environment or Docker clusters.