Definition of ZooKeeper

ZooKeeper Failover Controller (ZKFC) is the client of a ZooKeeper cluster that monitors the status of HDFS NameNodes. The ZKFC process is deployed only on the node where a NameNode is deployed. It can be deployed on both the active and standby NameNodes.

ZooKeeper Failover Controller (ZKFC) is the client of a ZooKeeper cluster that monitors the status of HDFS NameNodes. The ZKFC process is deployed only on the node where a NameNode is deployed. It can be deployed on both the active and standby NameNodes.

ZooKeeper Failover Controller (ZKFC) is the client of a ZooKeeper cluster that monitors the status of HDFS NameNodes. The ZKFC process is deployed only on the node where a NameNode is deployed. It can be deployed on both the active and standby NameNodes.

Kafka is a distributed, partitioned, and replicated message publishing and subscription system that provides features similar to the Java Message Service (JMS). Kafka features message persistence, high throughput, distribution, multi-client support, and real-time processing, and applies to online and offline message consumption. It is ideal for Internet service data collection scenarios, such as conventional data collection, active website tracing, aggregation of operation data in statistics systems (monitoring data), and log collection.

ZooKeeper is an open-source, distributed application coordination service. It prevents single points of failure and helps create reliable distributed applications.