diff --git a/experimental/compose_swarm_networking.md b/experimental/compose_swarm_networking.md index b1fb25dc4..905f52f80 100644 --- a/experimental/compose_swarm_networking.md +++ b/experimental/compose_swarm_networking.md @@ -1,183 +1,5 @@ # Experimental: Compose, Swarm and Multi-Host Networking -The [experimental build of Docker](https://github.com/docker/docker/tree/master/experimental) has an entirely new networking system, which enables secure communication between containers on multiple hosts. In combination with Docker Swarm and Docker Compose, you can now run multi-container apps on multi-host clusters with the same tooling and configuration format you use to develop them locally. +Compose now supports multi-host networking as standard. Read more here: -> Note: This functionality is in the experimental stage, and contains some hacks and workarounds which will be removed as it matures. - -## Prerequisites - -Before you start, you’ll need to install the experimental build of Docker, and the latest versions of Machine and Compose. - -- To install the experimental Docker build on a Linux machine, follow the instructions [here](https://github.com/docker/docker/tree/master/experimental#install-docker-experimental). - -- To install the experimental Docker build on a Mac, run these commands: - - $ curl -L https://experimental.docker.com/builds/Darwin/x86_64/docker-latest > /usr/local/bin/docker - $ chmod +x /usr/local/bin/docker - -- To install Machine, follow the instructions [here](https://docs.docker.com/machine/install-machine/). - -- To install Compose, follow the instructions [here](https://docs.docker.com/compose/install/). - -You’ll also need a [Docker Hub](https://hub.docker.com/account/signup/) account and a [Digital Ocean](https://www.digitalocean.com/) account. - -## Set up a swarm with multi-host networking - -Set the `DIGITALOCEAN_ACCESS_TOKEN` environment variable to a valid Digital Ocean API token, which you can generate in the [API panel](https://cloud.digitalocean.com/settings/applications). - - DIGITALOCEAN_ACCESS_TOKEN=abc12345 - -Start a consul server: - - docker-machine create -d digitalocean --engine-install-url https://experimental.docker.com consul - docker $(docker-machine config consul) run -d -p 8500:8500 -h consul progrium/consul -server -bootstrap - -(In a real world setting you’d set up a distributed consul, but that’s beyond the scope of this guide!) - -Create a Swarm token: - - SWARM_TOKEN=$(docker run swarm create) - -Create a Swarm master: - - docker-machine create -d digitalocean --swarm --swarm-master --swarm-discovery=token://$SWARM_TOKEN --engine-install-url="https://experimental.docker.com" --digitalocean-image "ubuntu-14-10-x64" --engine-opt=default-network=overlay:multihost --engine-label=com.docker.network.driver.overlay.bind_interface=eth0 --engine-opt=kv-store=consul:$(docker-machine ip consul):8500 swarm-0 - -Create a Swarm node: - - docker-machine create -d digitalocean --swarm --swarm-discovery=token://$SWARM_TOKEN --engine-install-url="https://experimental.docker.com" --digitalocean-image "ubuntu-14-10-x64" --engine-opt=default-network=overlay:multihost --engine-label=com.docker.network.driver.overlay.bind_interface=eth0 --engine-opt=kv-store=consul:$(docker-machine ip consul):8500 --engine-label com.docker.network.driver.overlay.neighbor_ip=$(docker-machine ip swarm-0) swarm-1 - -You can create more Swarm nodes if you want - it’s best to give them sensible names (swarm-2, swarm-3, etc). - -Finally, point Docker at your swarm: - - eval "$(docker-machine env --swarm swarm-0)" - -## Run containers and get them communicating - -Now that you’ve got a swarm up and running, you can create containers on it just like a single Docker instance: - - $ docker run busybox echo hello world - hello world - -If you run `docker ps -a`, you can see what node that container was started on by looking at its name (here it’s swarm-3): - - $ docker ps -a - CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES - 41f59749737b busybox "echo hello world" 15 seconds ago Exited (0) 13 seconds ago swarm-3/trusting_leakey - -As you start more containers, they’ll be placed on different nodes across the cluster, thanks to Swarm’s default “spread” scheduling strategy. - -Every container started on this swarm will use the “overlay:multihost” network by default, meaning they can all intercommunicate. Each container gets an IP address on that network, and an `/etc/hosts` file which will be updated on-the-fly with every other container’s IP address and name. That means that if you have a running container named ‘foo’, other containers can access it at the hostname ‘foo’. - -Let’s verify that multi-host networking is functioning. Start a long-running container: - - $ docker run -d --name long-running busybox top - - -If you start a new container and inspect its /etc/hosts file, you’ll see the long-running container in there: - - $ docker run busybox cat /etc/hosts - ... - 172.21.0.6 long-running - -Verify that connectivity works between containers: - - $ docker run busybox ping long-running - PING long-running (172.21.0.6): 56 data bytes - 64 bytes from 172.21.0.6: seq=0 ttl=64 time=7.975 ms - 64 bytes from 172.21.0.6: seq=1 ttl=64 time=1.378 ms - 64 bytes from 172.21.0.6: seq=2 ttl=64 time=1.348 ms - ^C - --- long-running ping statistics --- - 3 packets transmitted, 3 packets received, 0% packet loss - round-trip min/avg/max = 1.140/2.099/7.975 ms - -## Run a Compose application - -Here’s an example of a simple Python + Redis app using multi-host networking on a swarm. - -Create a directory for the app: - - $ mkdir composetest - $ cd composetest - -Inside this directory, create 2 files. - -First, create `app.py` - a simple web app that uses the Flask framework and increments a value in Redis: - - from flask import Flask - from redis import Redis - import os - app = Flask(__name__) - redis = Redis(host='composetest_redis_1', 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) - -Note that we’re connecting to a host called `composetest_redis_1` - this is the name of the Redis container that Compose will start. - -Second, create a Dockerfile for the app container: - - FROM python:2.7 - RUN pip install flask redis - ADD . /code - WORKDIR /code - CMD ["python", "app.py"] - -Build the Docker image and push it to the Hub (you’ll need a Hub account). Replace `` with your Docker Hub username: - - $ docker build -t /counter . - $ docker push /counter - -Next, create a `docker-compose.yml`, which defines the configuration for the web and redis containers. Once again, replace `` with your Hub username: - - web: - image: /counter - ports: - - "80:5000" - redis: - image: redis - -Now start the app: - - $ docker-compose up -d - Pulling web (username/counter:latest)... - swarm-0: Pulling username/counter:latest... : downloaded - swarm-2: Pulling username/counter:latest... : downloaded - swarm-1: Pulling username/counter:latest... : downloaded - swarm-3: Pulling username/counter:latest... : downloaded - swarm-4: Pulling username/counter:latest... : downloaded - Creating composetest_web_1... - Pulling redis (redis:latest)... - swarm-2: Pulling redis:latest... : downloaded - swarm-1: Pulling redis:latest... : downloaded - swarm-3: Pulling redis:latest... : downloaded - swarm-4: Pulling redis:latest... : downloaded - swarm-0: Pulling redis:latest... : downloaded - Creating composetest_redis_1... - -Swarm has created containers for both web and redis, and placed them on different nodes, which you can check with `docker ps`: - - $ docker ps - CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES - 92faad2135c9 redis "/entrypoint.sh redi 43 seconds ago Up 42 seconds swarm-2/composetest_redis_1 - adb809e5cdac username/counter "/bin/sh -c 'python 55 seconds ago Up 54 seconds 45.67.8.9:80->5000/tcp swarm-1/composetest_web_1 - -You can also see that the web container has exposed port 80 on its swarm node. If you curl that IP, you’ll get a response from the container: - - $ curl http://45.67.8.9 - Hello World! I have been seen 1 times. - -If you hit it repeatedly, the counter will increment, demonstrating that the web and redis container are communicating: - - $ curl http://45.67.8.9 - Hello World! I have been seen 2 times. - $ curl http://45.67.8.9 - Hello World! I have been seen 3 times. - $ curl http://45.67.8.9 - Hello World! I have been seen 4 times. +https://docs.docker.com/compose/networking