This image is the zookeeper dynamic conf for rancher. It comes from rawmind/rancher-tools.
docker build -t rawmind/rancher-zk:<version> .
This image has to be run as a sidekick of rawmind/alpine-zk, and makes available /opt/tools volume. It scans from rancher-metadata, for a zookeeper stack and generates /opt/zk/conf/zoo.cfg and /opt/zk/conf/myid dynamicly.