Step two: Build and install

Once you have set up your directory correctly, you can build your extension for single or multiple architectures.

Build the extension for a single architecture

To build the extension, run:

docker build -t <name-of-your-extension> .

Validate your extension

The Extensions CLI lets you validate your extension before installing and running it locally.

The validation checks if the extension’s Dockerfile specifies all the required labels and if the metadata file is valid against the JSON schema file.

To validate, run:

docker extension validate <name-of-your-extension>

If your extension is valid, the message below displays:

The extension image "name-of-your-extension" is valid.

Before the image is built, it is also possible to validate only the metadata.json file:

$ docker extension validate /path/to/metadata.json

The JSON schema used to validate the metadata.json file against can be found under the releases page.

Install the extension

To install the extension in Docker Desktop, run:

docker extension install <name-of-your-extension>


Extensions can install binaries, invoke commands and access files on your machine. Make sure you trust extensions before installing them on your machine.

To list all your installed extensions, run:

$ docker extension ls

ID                              PROVIDER            VERSION             UI                   VM                  HOST
docker/hub-explorer-extension   Docker Inc.         0.0.2               1 tab(Explore Hub)   Running(1)          1 binarie(s)

What’s next?

Learn how to test and debug your extension.

Docker, Extensions, sdk, validate, install