Configuring the ZooKeeper settings

Apache Zookeeper is a centralized service for maintaining configuration information providing distributed synchronization. ZooKeeper is used in Kafka for cluster management and to maintain the topics information synchronized.

Getting ready

With your favorite text editor, open your server.properties file copy.

How to do it…

Adjust the following parameters:

zookeeper.connect=127.0.0.1:2181,192.168.0.32:2181
zookeeper.session.timeout.ms=6000
zookeeper.connection.timeout.ms=6000
zookeeper.sync.time.ms=2000

How it works…

Here is an explanation of these settings:

• zookeeper.connect: Default value: null. This is a comma-separated value in the form of the hostname:port string, indicating the Zookeeper connection. Specifying several connections ensures the Kafka cluster reliability and continuity. When one node fails, Zookeeper uses the chroot path (/chroot/path) to make the data available under that particular path. This enables having the Zookeeper cluster available for multiple Kafka clusters. This path must be created before starting the Kafka cluster, and consumers must use the same string.
• zookeeper.session.timeout.ms: Default value: 6000. Session timeout means that if in this time period a heartbeat from the server is not received, it is considered dead. This parameter is fundamental, since if it is long and if the server is dead the whole system will experience problems. If it is small, a living server could be considered dead.
• zookeeper.connection.timeout.ms: Default value: 6000. This is the maximum time that the client will wait while establishing a connection to Zookeeper.
• zookeeper.sync.time.ms: Default value: 2000. This is the time a Zookeeper follower can be behind its Zookeeper leader.

See also

• From the Kafka perspective, the ZooKeeper parameters are detailed at: http://kafka.apache.org/documentation.html#brokerconfigs
• The Apache ZooKeeper home page is here: https://zookeeper.apache.org/