7.4.2.3. Using ZooKeeper for Cluster Coordination
There is an application component that enables dynamic discovery of middleware servers for communication between middleware blocks and for requesting middleware from client blocks. It is based on integration with Apache ZooKeeper - a centralized service for maintaining configuration information. When this component is included in your project, you need to specify only one static address when running your application blocks - the address of ZooKeeper. Middleware servers will advertise themselves by publishing their addresses on the ZooKeeper directory and discovery mechanisms will request ZooKeeper for addresses of available servers. If a middleware server goes down, it will be automatically removed from the directory immediately or after a timeout.