Based on:
https://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html#sc_systemReq
https://zookeeper.apache.org/doc/trunk/zookeeperStarted.html
The image building includes md5sum verification of the installation file.
Download or clone the repository and from inside the repository's directory execute:
docker build . -t docker-openwrt-zookeeper:3.4.10
To run a Zookeeper server listening on port 2181 execute:
docker run -p 2181:2181 docker-openwrt-zookeeper:3.4.10