compose/docs/yml.md

layout	title
default	fig.yml reference

fig.yml reference

Each service defined in fig.yml must specify exactly one of image or build. Other keys are optional, and are analogous to their docker run command-line counterparts.

As with docker run, options specified in the Dockerfile (e.g. CMD, EXPOSE, VOLUME, ENV) are respected by default - you don't need to specify them again in fig.yml.

-- Tag or partial image ID. Can be local or remote - Fig will attempt to pull if it doesn't exist locally.
image: ubuntu
image: orchardup/postgresql
image: a4bc65fd

-- Path to a directory containing a Dockerfile. Fig will build and tag it with a generated name, and use that image thereafter.
build: /path/to/build/dir

-- Override the default command.
command: bundle exec thin -p 3000

-- Link to containers in another service (see "Communicating between containers").
links:
 - db
 - redis

-- Expose ports. Either specify both ports (HOST:CONTAINER), or just the container port (a random host port will be chosen).
-- Note When mapping ports in the format HOST:CONTAINER you may experience erroneous results when using a container port lower than 60. This is due to YAML parsing numbers in the format "xx:yy" as sexagesimal (base 60) for this reason it is recommended to define your port mappings as strings.
ports:
 - "3000"
 - "8000:8000"
 - "49100:22"

-- Map volumes from the host machine (HOST:CONTAINER).
volumes:
 - cache/:/tmp/cache

-- Add environment variables.
environment:
  RACK_ENV: development