davidmr001/docker-zookeeper repository overview

⁠docker-zookeeper

The reason why we created this docker image is that we wanted to have a simple way to spin up multi-node ZooKeeper deployments. In particular, we wanted the docker container to create the ZooKeeper myID file autonomously, so that we could spawn ZooKeeper containers in single-line statements.
We are currently not aware of another easy approach to do that. More related resources:

⁠Simple multi-node ensembles

Suppose you wanted a 3-node ZooKeeper ensemble on machines with the hostnames zk1, zk2 and zk3, run the following on every ensemble node:

docker run -d --restart=always \
      -p 2181:2181 \
      -p 2888:2888 \
      -p 3888:3888 \
      -v /var/lib/zookeeper:/var/lib/zookeeper \
      -v /var/log/zookeeper:/var/log/zookeeper  \
      baqend/zookeeper zk1,zk2,zk3 $ID

Obviously, the -p commands expose the ports required by ZooKeeper per default. The two -v commands provide persistence in case of container failure by mapping the directories the ZooKeeper container uses to the corresponding host directories. The comma-separated list of hostnames tells ZooKeeper what servers are in the ensemble. This is the same for every node in the ensemble. The only variable is the ZooKeeper ID ($ID), because it is unique for every container. This means you have to provide every container with its ID (1, 2 and 3, respectively). And that's it.
All ZooKeeper-related data are stored on the host. On start, the ZooKeeper myID file is created anew.

Note: ZooKeeper only accepts IDs between 1 and 255!