Working with Docker Plugins

1. Installing Volume Plugins

Plugin Type	Description	Installation Method	Notes
volume	Enables Docker to use external storage systems as volumes	`docker plugin install`	Must be installed on the host machine where Docker runs

Example: Installing a Volume Plugin

docker plugin install --alias local-persist local/persist

Note: The --alias flag allows you to give a custom name to the plugin for easier reference in volume creation.

2. Listing Plugins

Command	Description	Options
docker plugin ls	List all installed plugins	`--format`, `--filter`
docker plugin ls --format json	Output in JSON format
docker plugin ls --filter name=plugin-name	Filter plugins by name

Example: Listing Plugins

docker plugin ls

Example: Listing Plugins with JSON Format

docker plugin ls --format json

Example: Filtering Plugins by Name

docker plugin ls --filter name=local-plugin

3. Inspecting Plugins

Command	Description	Example
docker plugin ls	List all installed plugins	`docker plugin ls`
docker plugin inspect <plugin-name>	Inspect a specific plugin's configuration and details	`docker plugin inspect example/plugin`

Example: Inspecting a Plugin

docker plugin inspect example/plugin

Note: The inspect command returns a JSON object containing plugin metadata, settings, and capabilities.

4. Enabling Plugins

Plugin	Enable Command	Description
docker-volume-local	`docker plugin enable local`	Enables the local volume driver plugin
docker-volume-aws	`docker plugin enable amazon/ec2`	Enables the AWS EBS volume driver plugin
docker-network-overlay	`docker plugin enable overlay`	Enables the overlay network driver plugin

Example: Enabling a Plugin

docker plugin enable local

Note: Plugins must be installed before they can be enabled.

5. Disabling Plugins

Plugin	Status	Command	Notes
example-plugin	DEPRECATED	`docker plugin disable example-plugin`	Plugin is deprecated as of Docker 25.0
volume-plugin	NEW	`docker plugin disable volume-plugin`	Available in Docker 26.0+

Example: Disabling a Plugin

docker plugin disable example-plugin

Note: Disabling a plugin does not remove it from the system. It can be re-enabled later using docker plugin enable.

6. Configuring Plugin Options

Option	Description	Default Value	Notes
--config	Path to the plugin configuration file	`null`	Used to specify a custom config file for plugin settings
--env	Set environment variables for the plugin	`null`	Can be used to pass runtime configuration to the plugin
--volume	Mount a volume into the plugin container	`null`	Allows access to host filesystem from within the plugin

Example: Setting Plugin Configuration

docker plugin install --config /etc/plugin-config.json my-plugin

Example: Setting Environment Variables

docker plugin install --env MY_VAR=value my-plugin

Note: Plugin configuration options are defined by the plugin developer and may vary depending on the plugin type.

7. Using Network Plugins

Plugin	Description	Usage	Notes
bridge	Default network driver for containers	`docker run --network bridge <image>`	Isolated network namespace per container
host	Shares host network namespace	`docker run --network host <image>`	Bypasses Docker networking
none	No network access for container	`docker run --network none <image>`	Container has no network interface
overlay	Connects multiple Docker daemons	`docker network create --driver overlay <name>`	Used in swarm mode for multi-host networks

Example: Creating an Overlay Network

docker network create --driver overlay --subnet=10.0.9.0/24 my-overlay-network

Note: Overlay networks require a key-value store like Consul, Etcd, or ZooKeeper to manage the network configuration across multiple Docker daemons.

Example: Attaching a Service to an Overlay Network

docker service create --name my-service --network my-overlay-network nginx

Warning: Ensure that the key-value store is properly configured before creating overlay networks in swarm mode.

8. Using Storage Plugins

Property	Value	Description
driver	`local`	Default storage driver for Docker volumes
driver	`overlay2`	Recommended for production environments
driver	`btrfs`	For systems with Btrfs filesystem support
driver	`zfs`	For systems with ZFS filesystem support

Example: Configure Storage Driver

{
  "storage-driver": "overlay2"
}

Note: The storage driver must be set at Docker daemon startup and cannot be changed without reconfiguring the daemon.

Warning: Changing storage drivers after data has been written can lead to data loss or corruption.

Driver	Supported OS	Features	Notes
`local`	All	Basic volume management	Simple and lightweight, not suitable for multi-host setups
`overlay2`	Linux	Multi-layered, efficient	Default in modern Docker versions
`btrfs`	Linux	Snapshot support, compression	Requires Btrfs filesystem
`zfs`	Linux, FreeBSD	Snapshotting, compression, encryption	Requires ZFS filesystem

9. Upgrading Plugins

Command	Description	Notes
docker plugin upgrade <plugin>	Upgrades a Docker plugin to the latest version	Requires plugin to be disabled first
docker plugin upgrade --grant-all-permissions <plugin>	Upgrades plugin and grants all permissions	Useful for plugins requiring extensive access

Example: Upgrading a Plugin

# Disable plugin before upgrade
docker plugin disable example/plugin:latest

# Upgrade plugin to latest version
docker plugin upgrade example/plugin:latest

# Re-enable plugin after upgrade
docker plugin enable example/plugin:latest

Note: Plugin upgrades may require disabling and re-enabling the plugin to take effect.

Warning: Ensure compatibility with current Docker version before upgrading plugins.

10. Creating Custom Plugins

Creating custom Docker plugins allows you to extend Docker's functionality with your own logic and features. Plugins are built as separate executables that communicate with the Docker daemon via a defined API.

Component	Description	Details
Plugin Structure	Directory layout of a plugin	`my-plugin/ ├── plugin.json └── my-plugin-binary`
plugin.json	Plugin manifest file	Defines plugin metadata, capabilities, and configuration.

Example: plugin.json

{
  "name": "my-plugin",
  "description": "A custom Docker plugin",
  "version": "1.0.0",
  "capabilities": [
    "volume"
  ],
  "apiVersion": "1.0"
}

Note: The plugin binary must be executable and placed in the same directory as plugin.json.

Workflow: Creating a Custom Plugin

Create a directory for your plugin.
Write the plugin binary in any language that supports command-line interfaces (e.g., Go, Python).
Define the plugin metadata in plugin.json.
Ensure the binary is executable and placed in the plugin directory.
Install the plugin using docker plugin install.

Plugin Types

Volume Plugins: Extend storage capabilities.
Network Plugins: Manage network connectivity and routing.
Log Plugins: Handle logging output from containers.

11. Managing Plugin Permissions

Permission	Description	Default Scope	Notes
docker plugin install --grant-all-permissions	Installs a plugin and grants all permissions	All permissions	Use with caution as it grants full access to the Docker daemon
docker plugin install --grant-permission	Installs a plugin and grants specific permissions	Selected permissions	Allows fine-grained control over plugin access
docker plugin ls --filter capability=	Lists plugins with specific capabilities	Filtered by capability	Useful for auditing plugin permissions

Example: Installing a Plugin with Specific Permissions

docker plugin install --grant-permission network --grant-permission volume example/plugin

Note: Plugin permissions are managed at the Docker daemon level and can be configured via the daemon.json file.

Warning: Granting all permissions to a plugin can pose security risks. Always review the plugin's capabilities before granting permissions.

12. Removing Plugins

Command	Description	Notes
docker plugin rm <plugin-name>	Remove a plugin	Plugin must be disabled before removal
docker plugin rm <plugin-name> --force	Force remove a plugin	Removes plugin even if it's enabled

Example: Removing a Plugin

docker plugin disable my-plugin
docker plugin rm my-plugin

Note: Ensure the plugin is not in use before removal to avoid unexpected behavior.