The ZooKeeper Service

Minimum Required Role: Full Administrator

When adding the ZooKeeper service, the Add Service wizard automatically initializes the data directories. If you quit the Add Service wizard or it does not finish successfully, you can initialize the directories outside the wizard by doing these steps:
  1. Go to the ZooKeeper service.
  2. Select Actions > Initialize.
  3. Click Initialize again to confirm.

In a production environment, you should deploy ZooKeeper as an ensemble with an odd number of servers. As long as a majority of the servers in the ensemble are available, the ZooKeeper service will be available. The minimum recommended ensemble size is three ZooKeeper servers, and Cloudera recommends that each server run on a separate machine. In addition, the ZooKeeper server process should have its own dedicated disk storage if possible.

Using Multiple ZooKeeper Services

Cloudera Manager requires dependent services within CDH to use the same ZooKeeper service. If you configure dependent CDH services to use different ZooKeeper services, Cloudera Manager reports the following error:

com.cloudera.cmf.command.CmdExecException:java.lang.RuntimeException: java.lang.IllegalStateException: Assumption violated:
getAllDependencies returned multiple distinct services of the same type
at SeqFlowCmd.java line 120
in com.cloudera.cmf.command.flow.SeqFlowCmd run()

CDH services that are not dependent can use different ZooKeeper services. For example, Kafka does not depend on any services other than ZooKeeper. You might have one ZooKeeper service for Kafka, and one ZooKeeper service for the rest of your CDH services.