NOTE: this is out of date - refer to moby/moby#9694
Here is a preview build of two new features we’re working on concurrently: container grouping (docker groups) and stack composition (docker up). Together, they will eventually form a complete replacement for Fig.
- linux/amd64: http://cl.ly/2c3p40251H11/download/docker-1.3.1-dev-linux
- darwin/386: http://cl.ly/0P0s452H3t0x/download/docker-1.3.1-dev-darwin-386
- darwin/amd64: http://cl.ly/1U1A0W2e0Y3u/download/docker-1.3.1-dev-darwin-amd64
Here's how to test it out if you're running boot2docker. First, replace the binary in your VM:
$ boot2docker ssh
docker@boot2docker:~$ sudo -i
root@boot2docker:~# curl -LO http://cl.ly/2c3p40251H11/download/docker-1.3.1-dev-linux
root@boot2docker:~# /etc/init.d/docker stop
root@boot2docker:~# mv /usr/local/bin/docker ./docker-stable
root@boot2docker:~# mv ./docker-1.3.1-dev-linux /usr/local/bin/docker
root@boot2docker:~# chmod +x /usr/local/bin/docker
root@boot2docker:~# /etc/init.d/docker start
root@boot2docker:~# docker version # both "Git commit"s should be 56d8c9e
root@boot2docker:~# exit
docker@boot2docker:~$ exit
Next, replace your client binary:
$ curl -LO http://cl.ly/1U1A0W2e0Y3u/download/docker-1.3.1-dev-darwin-amd64
$ mv /usr/local/bin/docker ./docker-stable
$ mv ./docker-1.3.1-dev-darwin-amd64 /usr/local/bin/docker
$ chmod +x /usr/local/bin/docker
$ docker version # both "Git commit"s should be 56d8c9e
The idea of stack composition is that with a very simple group.yml which describes what containers you want your application to consist of, you can type docker up and Docker will do everything necessary to get it running - including building or pulling any required images.
I demonstrated this functionality a couple of weeks ago in this screencast; this build is similar to that demoed but differs in that the shared-hosts-file approach has been ditched in favour of a Fig-style links keyword. More on that in the proposal discussion.
Here’s a sample app you can try:
app.py:
from flask import Flask
from redis import Redis
app = Flask(__name__)
redis = Redis(host="redis", port=6379)
@app.route('/')
def hello():
redis.incr('hits')
return 'Hello World! I have been seen %s times.' % redis.get('hits')
if __name__ == "__main__":
app.run(host="0.0.0.0", debug=True)requirements.txt:
flask
redis
Dockerfile:
FROM python:2.7
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt
group.yml:
name: counter
containers:
web:
build: .
command: python app.py
ports:
- "5000:5000"
volumes:
- .:/code
links:
- redis
environment:
- PYTHONUNBUFFERED=1
redis:
image: redis:latest
command: redis-server --appendonly yesIf you put those four files in a directory and type docker up, you should see everything start up:
It'll build the web image, pull the redis image, start both containers and stream their aggregated output. If you Ctrl-C, it'll shut them down.
Your app will run in a group, which is a new way of keeping multiple related containers organised. The docker groups command lets you list, create and delete groups, and also bulk start/stop/kill the containers within them. To find out more about that, run docker groups -h.
Groups are created by posting JSON to the daemon with the configuration info for all containers. docker up posts to that endpoint with a JSON payload generated from group.yml, and is responsible for automatically building and pulling images before doing so. To get a feel for the separation, try this:
$ docker up --parse > group.json
$ docker groups create - < group.json
$ docker groups start counter
That's essentially equivalent to docker up -d.
A group has a unique name which exists in the same namespace as containers. This app's group is called counter, as specified in group.yml. Its containers are called counter/web and counter/redis, and you can perform all the normal docker commands on them (e.g. docker inspect counter/web).
You can also start a new container in an existing group with docker run --group, e.g. docker run --group counter busybox echo hello world.
You can list just the containers in a specific group with docker ps GROUPNAME.
Finally, some docker commands have been augmented with an experimental syntax for picking up names from group.yml:
# list containers within the group defined in group.yml
$ docker ps :
# start/stop/kill/remove all containers in the current group
$ docker groups [start|stop|kill|rm] :
# start/stop/kill/remove the web container
$ docker [start|stop|kill|rm] :web
# run a bash shell in the web container
$ docker exec -ti :web bash
# pull the image specified under 'redis' in group.yml, i.e. 'redis:latest'
$ docker pull :redis
# build image for 'web' using the directory specified under 'web' in group.yml, i.e. '.'
$ docker build :web
There are a few things left to do before this constitutes a Fig replacement, including:
- Supporting
volumes_from - An equivalent to
fig run, which runs a one-off container with image and configuration picked up fromgroup.yml. (docker execcovers some of the use cases but not all, and requires a container to already be running) - An equivalent to
fig logs, which streams the logs of already-running containers. docker groups (pause|unpause|restart)- Validation of the YAML file
- Nicer output for
ps(giving more prominence to names over IDs, and perhaps doing away with the long list of names in the default display) - We should think about scaling. I don't think an equivalent to
fig scaleis necessary on day one, but it will eventually be needed as Docker becomes a multi-host platform, so there shouldn't be anything in the design that'll make that difficult to implement later. - Code cleanup
- Tests!
To get hacking, check out the composition branch on my fork:
$ git checkout -b composition master
$ git pull [email protected]:aanand/docker.git composition
Hi:
The docker source tree on my box is updated as of 2014-11-10. Building the docker-1.3.1-dev binary on CentOS 7 does not show the 'group' and 'up' options when i run docker.