- Install ZooKeeper. Execute the following command on all the ZooKeeper nodes: - For RHEL/CentOS: - yum upgrade zookeeper* 
- For SLES: - zypper remove zookeeper zypper install zookeeper - Note that the command uninstalls HBase. Execute the following command to re-install HBase: - zypper install hbase ![[Important]](../common/images/admon/important.png) - Important - When removing and installing packages, rename those files under the - /confdirectory that have- .rpmsaveextension to original to retain the customized configs. Or, you can also use the configuration files (under the- /confdirectory) that you backed up before upgrading.
 
- Start ZooKeeper. On all the ZooKeeper host machines, execute the following command: - sudo su -l $ZOOKEEPER_USER -c "source /etc/zookeeper/conf/zookeeper-env.sh; export ZOOCFGDIR=/etc/zookeeper/conf; /usr/lib/zookeeper/bin/zkServer.sh start >> $ZOOKEEPER_LOG_DIR/zoo.out" - where - $ZOOKEEPER_USERis the ZooKeeper Service user. For example,- zookeeper.
- $ZOOKEEPER_LOG_DIRis the directory where ZooKeeper server logs are stored. For example,- /var/log/zookeeper.
 
- Execute the following commands on the HBase Master and the HBase slave nodes (RegionServers): - For RHEL/CentOS: - yum upgrade hbase 
- For SLES: - zypper update hbase 
 
- Start HBase. - Start HBase Master. On the HBase Master host machine, execute the following command: - sudo su -l $HBASE_USER -c "/usr/lib/hbase/bin/hbase-daemon.sh --config /etc/hbase/conf start master" 
- Start all RegionServers. On all the RegionServers, execute the following command: - sudo su -l $HBASE_USER -c "/usr/lib/hbase/bin/hbase-daemon.sh --config /etc/hbase/conf start regionserver" - where - $HBASE_USERis the HBase Service user. For example,- hbase.
 


