This project is about leader election using zookeeper in which each jvm process will be leader or followers or observer. There can be only one leader at time and when that leader goes down then any of follower should became leader. Observer should not take participate in election but they need a leader too and without leader they should complain.

Requirement:

1. Java-1.7

2. Maven-3.x.x(To build project)

3. Zookeeper-3.4.6

mvn clean package

This will create target directory with executable jar file(leader-election-1.0-jar-with-dependencies.jar).

You can read about zookeeper from here. From its getting started page you can bring up zookeeper server. By default zookeeper should be started on 2181 port and ip address will be host address of zookeeper.

You can start node by following command. Replace zookeeper host and zookeeper port.

java -jar leader-election-1.0-jar-with-dependencies.jar Ironman zookeeper_host:zookeeper_port   # Ironman node
java -jar leader-election-1.0-jar-with-dependencies.jar Hulk zookeeper_host:zookeeper_port   # Hulk node

Same name will not effect functionality but it is advised to choose unique name so that it will easy to distinguish which is leader now. By starting above node in order, Ironman will became leader and Hulk will became follower and when Ironman will be down then Hulk will became new leader and so on.

java -jar leader-election-1.0-jar-with-dependencies.jar Batman zookeeper_host:zookeeper_port observer     # Batman observer