dokku/docs/advanced-usage/docker-options.md

Docker Container Options

New as of 0.3.17

Pass options to Docker during Dokku's build, deploy and run phases

docker-options <app> [phase(s)]               # Display app's Docker options for all phases (or comma separated phase list)
docker-options:add <app> <phase(s)> OPTION    # Add Docker option to app for phase (comma-separated phase list)
docker-options:remove <app> <phase(s)> OPTION # Remove Docker option from app for phase (comma-separated phase list)

When specifying multiple phases, they must be comma-separated without spaces in between each phase, like so:

dokku docker-options:add myapp deploy,run "-v /home/dokku/logs/myapp:/app/logs"

About Dokku phases

Dokku deploys your application in multiple "phases" and the docker-options plugin allows you to pass arguments to their underlying docker container:

• build: the container that executes the appropriate buildpack
• deploy: the container that executes your running/deployed application
• run: the container that executes any arbitrary command via dokku run myapp

Examples

Add Docker options

Add some options for the deployed/running app and when executing dokku run:

# Mount a host volume in a Docker container: "-v /host/path:/container/path"
dokku docker-options:add myapp deploy "-v /home/dokku/logs/myapp:/app/logs"
dokku docker-options:add myapp run "-v /home/dokku/logs/myapp:/app/logs"

Note: When mounting a host directory in a Dokku app you should first create that directory as user dokku and then mount the directory under /app in the container using docker-options as above. Otherwise the app will lack write permission in the directory.

Output Docker options

dokku docker-options myapp

Deploy options:
   -v /home/dokku/logs/myapp:/app/logs
Run options:
   -v /home/dokku/logs/myapp:/app/logs

Remove a Docker option

dokku docker-options:remove myapp run "-v /home/dokku/logs/myapp:/app/logs"

Advanced usage

In your applications folder /home/dokku/app_name create a file called DOCKER_OPTIONS_RUN (or DOCKER_OPTIONS_BUILD or DOCKER_OPTIONS_DEPLOY).

Inside this file list one Docker option per line. For example:

--link container_name:alias
-v /host/path:/container/path
-v /another/container/path

The above example will result in the following options being passed to Docker during dokku run:

--link container_name:alias -v /host/path:/container/path -v /another/container/path

You may also include comments (lines beginning with a #) and blank lines in the DOCKER_OPTIONS file.

More information on Docker options can be found here: https://docs.docker.com/engine/reference/commandline/run/.