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.

image

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

build

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

command

Override the default command.

command: bundle exec thin -p 3000

links

Link to containers in another service. Either specify both the service name and the link alias (SERVICE:ALIAS), or just the service name (which will also be used for the alias).

links:
 - db
 - db:database
 - redis

An entry with the alias' name will be created in /etc/hosts inside containers for this service, e.g:

172.17.2.186  db
172.17.2.186  database
172.17.2.187  redis

Environment variables will also be created - see the environment variable reference for details.

ports

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 HOST:CONTAINER format, you may experience erroneous results when using a container port lower than 60, because YAML will parse numbers in the format xx:yy as sexagesimal (base 60). For this reason, we recommend always explicitly specifying your port mappings as strings.

ports:
 - "3000"
 - "8000:8000"
 - "49100:22"
 - "127.0.0.1:8001:8001"

expose

Expose ports without publishing them to the host machine - they'll only be accessible to linked services. Only the internal port can be specified.

expose:
 - "3000"
 - "8000"

volumes

Mount paths as volumes, optionally specifying a path on the host machine (HOST:CONTAINER), or an access mode (HOST:CONTAINER:ro).

volumes:
 - /var/lib/mysql
 - cache/:/tmp/cache
 - ~/configs:/etc/configs/:ro

volumes_from

Mount all of the volumes from another service or container.

volumes_from:
 - service_name
 - container_name

environment

Add environment variables. You can use either an array or a dictionary.

Environment variables with only a key are resolved to their values on the machine Fig is running on, which can be helpful for secret or host-specific values.

environment:
  RACK_ENV: development
  SESSION_SECRET:

environment:
  - RACK_ENV=development
  - SESSION_SECRET

net

Networking mode. Use the same values as the docker client --net parameter.

net: "bridge"
net: "none"
net: "container:[name or id]"
net: "host"

dns

Custom DNS servers. Can be a single value or a list.

dns: 8.8.8.8
dns:
  - 8.8.8.8
  - 9.9.9.9

working_dir, entrypoint, user, hostname, domainname, mem_limit, privileged

Each of these is a single value, analogous to its docker run counterpart.

working_dir: /code
entrypoint: /code/entrypoint.sh
user: postgresql

hostname: foo
domainname: foo.com

mem_limit: 1000000000
privileged: true