Swarm cluster

Swarm cluster

This section explains how to create a multi-host swarm cluster using docker-machine and how to deploy Traefik on it.

The cluster consists of:

2 servers
1 swarm master
2 swarm nodes
1 overlay network (multi-host networking)

Prerequisites

You need to install docker-machine
You need the latest VirtualBox

Cluster provisioning

We first follow this guide to create the cluster.

Create machine mh-keystore

This machine is the service registry of our cluster.

docker-machine create -d virtualbox mh-keystore

Then we install the service registry Consul on this machine:

eval "$(docker-machine env mh-keystore)"
docker run -d \
    -p "8500:8500" \
    -h "consul" \
    progrium/consul -server -bootstrap

Create machine mhs-demo0

This machine is a swarm master and a swarm agent on it.

docker-machine create -d virtualbox \
    --swarm --swarm-master \
    --swarm-discovery="consul://$(docker-machine ip mh-keystore):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip mh-keystore):8500" \
    --engine-opt="cluster-advertise=eth1:2376" \
    mhs-demo0

Create machine mhs-demo1

This machine have a swarm agent on it.

docker-machine create -d virtualbox \
    --swarm \
    --swarm-discovery="consul://$(docker-machine ip mh-keystore):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip mh-keystore):8500" \
    --engine-opt="cluster-advertise=eth1:2376" \
    mhs-demo1

Create the overlay Network

Create the overlay network on the swarm master:

eval $(docker-machine env --swarm mhs-demo0)
docker network create --driver overlay --subnet=10.0.9.0/24 my-net

Deploy Traefik

Deploy Traefik:

docker $(docker-machine config mhs-demo0) run \
    -d \
    -p 80:80 -p 8080:8080 \
    --net=my-net \
    -v /var/lib/boot2docker/:/ssl \
    traefik:<stable version from https://hub.docker.com/_/traefik> \
    -l DEBUG \
    -c /dev/null \
    --docker \
    --docker.domain=traefik \
    --docker.endpoint=tcp://$(docker-machine ip mhs-demo0):2376 \
    --docker.tls \
    --docker.tls.ca=/ssl/ca.pem \
    --docker.tls.cert=/ssl/server.pem \
    --docker.tls.key=/ssl/server-key.pem \
    --docker.tls.insecureSkipVerify \
    --docker.watch \
    --api

Let's explain this command:

Option	Description
`-p 80:80 -p 8080:8080`	we bind ports 80 and 8080
`--net=my-net`	run the container on the network my-net
`-v /var/lib/boot2docker/:/ssl`	mount the ssl keys generated by docker-machine
`-c /dev/null`	empty config file
`--docker`	enable docker provider
`--docker.endpoint=tcp://172.18.0.1:2376`	connect to the swarm master using the docker_gwbridge network
`--docker.tls`	enable TLS using the docker-machine keys
`--api`	activate the webUI on port 8080

Deploy your apps

We can now deploy our app on the cluster, here whoami, a simple web server in GO, on the network my-net:

eval $(docker-machine env --swarm mhs-demo0)
docker run -d --name=whoami0 --net=my-net --env="constraint:node==mhs-demo0" containous/whoami
docker run -d --name=whoami1 --net=my-net --env="constraint:node==mhs-demo1" containous/whoami

Check that everything is started:

docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                                      NAMES
ba2c21488299        containous/whoami   "/whoamI"                8 seconds ago       Up 9 seconds        80/tcp                                                     mhs-demo1/whoami1
8147a7746e7a        containous/whoami   "/whoamI"                19 seconds ago      Up 20 seconds       80/tcp                                                     mhs-demo0/whoami0
8fbc39271b4c        traefik             "/traefik -l DEBUG -c"   36 seconds ago      Up 37 seconds       192.168.99.101:80->80/tcp, 192.168.99.101:8080->8080/tcp   mhs-demo0/serene_bhabha

Access to your apps through Traefik

curl -H Host:whoami0.traefik http://$(docker-machine ip mhs-demo0)

Hostname: 8147a7746e7a
IP: 127.0.0.1
IP: ::1
IP: 10.0.9.3
IP: fe80::42:aff:fe00:903
IP: 172.18.0.3
IP: fe80::42:acff:fe12:3
GET / HTTP/1.1
Host: 10.0.9.3:80
User-Agent: curl/7.35.0
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 192.168.99.1
X-Forwarded-Host: 10.0.9.3:80
X-Forwarded-Proto: http
X-Forwarded-Server: 8fbc39271b4c

curl -H Host:whoami1.traefik http://$(docker-machine ip mhs-demo0)

Hostname: ba2c21488299
IP: 127.0.0.1
IP: ::1
IP: 10.0.9.4
IP: fe80::42:aff:fe00:904
IP: 172.18.0.2
IP: fe80::42:acff:fe12:2
GET / HTTP/1.1
Host: 10.0.9.4:80
User-Agent: curl/7.35.0
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 192.168.99.1
X-Forwarded-Host: 10.0.9.4:80
X-Forwarded-Proto: http
X-Forwarded-Server: 8fbc39271b4c

Swarm Cluster