Configure and Start Apache ZooKeeper
![[Tip]](../common/images/admon/tip.png) | Tip |
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If you are running a highly available HDFS cluster, configure and restart Apache ZooKeeper before you upgrade HDFS. This best practice lets the upgraded ZKFC work with your primary NameNode and your Standby NameNode. |
Replace your configuration after upgrading on all the ZooKeeper nodes. Replace the ZooKeeper template configuration in
/etc/zookeeper/conf.Start ZooKeeper.
On all ZooKeeper server host machines, run the following command to start ZooKeeper and the ZKFC:
su - zookeeper -c "/usr/hdf/current/zookeeper-server/bin/zookeeper-server start"