Overview

This project creates a docker-based Zookeeper container that supports dynamically changing the enemble configuration based on consul service discovery. This allows you to spin up and modify ZK ensembles quickly.

Warning! This is a test of consul-template. Don't use for anything important at this time, as we haven't tested various failure scenarios.

Features

• Uses consul-template to dynamicaly write zoo.cfg and restart Zookeeper
• Supplies environment variables for registrator for service discovery
• Configurable via environment variables passed to container
• Supports docker-assigned ports for client, peer and leaders (you can run multiple zookeepers on the same machine without port conflicts)
• Will generate random ZKIDs if one is not provided
• Supports tagging for use with registrator and consul service discovery

Building

This image is available in the Docker hub as asteris/zookeeper:latest. To build your own use the included Makefile. You can override any of the NAME, REPO or TAG:

cd zookeeper-3.4
NAME=zk make -e
REPO=mycompany NAME=zk TAG=test make -e tag

Pushing to the Docker hub:

REPO=mycompany NAME=zk TAG=test make -e push

Running

From the command line

• Ensure that consul is running. We recommend using the instructions from docker-consul. The container should be named consul

• Ensure that registrator is running:

      -v /var/run/docker.sock:/tmp/docker.sock \
      -h $HOSTNAME progrium/registrator```
  
  

• Optional: configure dnsmasq to use consul for DNS. See http://www.morethanseven.net/2014/04/25/consul/

• Run ./start_container.sh

• If you want to use Consul DNS instead of container linking, replace the --link consul:consul line in the script with a CONSUL_CONNECT pointing to the dns name of the consul system

Environment variables

Variable	Default	Description
CONSUL_CONNECT	consul:8500	DNS name of consul server. If using dnsmasq + consul you can use consul.service.consl instead and pass --dns=127.0.0.1 when starting the container
CONSUL_MINWAIT	20s	Consul template minimum wait
CONSUL_MAXWAIT	60s	Consul template maximum wait
CONSUL_QUERY	${CONSUL_SERVICE} if ${CONSUL_TAG} is defined the default will be ${CONSUL_TAG}.${CONSUL_SERVICE}	Consul template query. For example, set the tag & service name to have consul template look for systems like: cluster1.zookeeper
CONSUL_SERVICE	zookeeper	Consul Service discovery name
CONSUL_TAG	Not defined	Consul Service discovery tag
ZOO_LOG_DIR	${ZK_LOG_DIR}	log4j zookeeper.out file location
ZK_DATA_DIR	/var/lib/zookeeper	location of Zookeeper data
ZK_LOG_DIR	/var/log/zookeeper	location of Zookeeper dataLog
ZK_HOME	/opt/zookeeper	Zookeeper install directory
ZK_ID	1	Zookeeper serverid

##License This software is released under an Apache 2.0 License

Copyright Asteris, LLC 2014