These instructions, and the included redis.conf file, provide a working Redis Cluster running on Docker Swarm. You should be running recent versions of both Redis and Docker; I'm running Redis v3.2.1 and Docker 1.11.2. If you're using Windows or a Mac, I strongly recommend installing Docker using Docker Toolbox.
First, we'll need a swarm discovery token.
token=$(docker run swarm create)
Create the swarm master machine.
docker-machine create -d virtualbox --swarm --swarm-master --swarm-discovery token://$token swarm-master
Create six Redis machines to cluster.
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-1
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-2
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-3
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-4
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-5
docker-machine create -d virtualbox --swarm --swarm-discovery token://$token redis-6
List the machines we've created so far, taking note of their IP addresses.
docker-machine ls
Set docker-machine and the local shell to use the swarm master we created earlier.
docker-machine env --swarm swarm-master
eval $(docker-machine env --swarm swarm-master)
Create the Redis instances to cluster. All paths, including the path to the local copy of the redis.conf file, must be absolute. The --net=host option is necessary for Redis Cluster's discovery to work.
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis1 redis redis-server /usr/local/etc/redis/redis.conf
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis2 redis redis-server /usr/local/etc/redis/redis.conf
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis3 redis redis-server /usr/local/etc/redis/redis.conf
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis4 redis redis-server /usr/local/etc/redis/redis.conf
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis5 redis redis-server /usr/local/etc/redis/redis.conf
docker run -v <PATH_TO>/redis.conf:/usr/local/etc/redis/redis.conf -d --net=host --name redis6 redis redis-server /usr/local/etc/redis/redis.conf
List running instances, making sure all the instances we created in the last step are listed as "Up."
docker ps
redis-trib manages the cluster for us. We'll download it from the Redis GitHub repo.
curl -O https://raw.githubusercontent.com/antirez/redis/unstable/src/redis-trib.rb
We'll also need the Redis Ruby gem.
gem install redis
Now we can create the cluster from the Redis instances we created earlier.
./redis-trib.rb create --replicas 1 <redis1_IP>:6379 <redis2_IP>:6379 <redis3_IP>:6379 <redis4_IP>:6379 <redis5_IP>:6379 <redis6_IP>:6379
Finally, use the Redis CLI client to connect to one of the Redis instances and test the cluster.
redis-cli -c -h <redis1_IP> -p 6379