--- description: Develop and use a plugin with the managed plugin system keywords: "API, Usage, plugins, documentation, developer" title: Managed plugin system --- <!-- This file is maintained within the docker/docker Github repository at https://github.com/docker/docker/. Make all pull requests against that repo. If you see this file in another repository, consider it read-only there, as it will periodically be overwritten by the definitive file. Pull requests which include edits to this file in other repositories will be rejected. --> # Docker Engine managed plugin system * [Installing and using a plugin](index.md#installing-and-using-a-plugin) * [Developing a plugin](index.md#developing-a-plugin) Docker Engine's plugins system allows you to install, start, stop, and remove plugins using Docker Engine. This mechanism is currently only available for volume drivers, but more plugin driver types will be available in future releases. For information about the legacy plugin system available in Docker Engine 1.12 and earlier, see [Understand legacy Docker Engine plugins](legacy_plugins.md). > **Note**: Docker Engine managed plugins are currently not supported on Windows daemons. ## Installing and using a plugin Plugins are distributed as Docker images and can be hosted on Docker Hub or on a private registry. To install a plugin, use the `docker plugin install` command, which pulls the plugin from Docker hub or your private registry, prompts you to grant permissions or capabilities if necessary, and enables the plugin. To check the status of installed plugins, use the `docker plugin ls` command. Plugins that start successfully are listed as enabled in the output. After a plugin is installed, you can use it as an option for another Docker operation, such as creating a volume. In the following example, you install the `sshfs` plugin, verify that it is enabled, and use it to create a volume. 1. Install the `sshfs` plugin. ```bash $ docker plugin install vieux/sshfs Plugin "vieux/sshfs" is requesting the following privileges: - network: [host] - capabilities: [CAP_SYS_ADMIN] Do you grant the above permissions? [y/N] y vieux/sshfs ``` The plugin requests 2 privileges: - It needs access to the `host` network. - It needs the `CAP_SYS_ADMIN` capability, which allows the plugin to run the `mount` command. 2. Check that the plugin is enabled in the output of `docker plugin ls`. ```bash $ docker plugin ls NAME TAG ENABLED vieux/sshfs latest true ``` 3. Create a volume using the plugin. This example mounts the `/remote` directory on host `1.2.3.4` into a volume named `sshvolume`. This volume can now be mounted into containers. ```bash $ docker volume create \ -d vieux/sshfs \ --name sshvolume \ -o sshcmd=user@1.2.3.4:/remote sshvolume ``` 4. Verify that the volume was created successfully. ```bash $ docker volume ls DRIVER NAME vieux/sshfs sshvolume ``` 5. Start a container that uses the volume `sshvolume`. ```bash $ docker run -v sshvolume:/data busybox ls /data <content of /remote on machine 1.2.3.4> ``` To disable a plugin, use the `docker plugin disable` command. To completely remove it, use the `docker plugin remove` command. For other available commands and options, see the [command line reference](../reference/commandline/index.md). ## Developing a plugin #### The rootfs directory The `rootfs` directory represents the root filesystem of the plugin. In this example, it was created from a Dockerfile: >**Note:** The `/run/docker/plugins` directory is mandatory inside of the plugin's filesystem for docker to communicate with the plugin. ```bash $ git clone https://github.com/vieux/docker-volume-sshfs $ cd docker-volume-sshfs $ docker build -t rootfsimage . $ id=$(docker create rootfsimage true) # id was cd851ce43a403 when the image was created $ sudo mkdir -p myplugin/rootfs $ sudo docker export "$id" | sudo tar -x -C myplugin/rootfs $ docker rm -vf "$id" $ docker rmi rootfsimage ``` #### The config.json file The `config.json` file describes the plugin. See the [plugins config reference](config.md). Consider the following `config.json` file. ```json { "description": "sshFS plugin for Docker", "documentation": "https://docs.docker.com/engine/extend/plugins/", "entrypoint": ["/go/bin/docker-volume-sshfs"], "network": { "type": "host" }, "interface" : { "types": ["docker.volumedriver/1.0"], "socket": "sshfs.sock" }, "capabilities": ["CAP_SYS_ADMIN"] } ``` This plugin is a volume driver. It requires a `host` network and the `CAP_SYS_ADMIN` capability. It depends upon the `/go/bin/docker-volume-sshfs` entrypoint and uses the `/run/docker/plugins/sshfs.sock` socket to communicate with Docker Engine. This plugin has no runtime parameters. ### Creating the plugin A new plugin can be created by running `docker plugin create <plugin-name> ./path/to/plugin/data` where the plugin data contains a plugin configuration file `config.json` and a root filesystem in subdirectory `rootfs`. After that the plugin `<plugin-name>` will show up in `docker plugin ls`. Plugins can be pushed to remote registries with `docker plugin push <plugin-name>`.