Download Apache ZooKeeper "3.9.3": http://zookeeper.apache.org/releases.html

Extract the file "apache-zookeeper-3.9.3-bin.tar.gz" in the folder you want to install ZooKeeper:
► /opt/apache-zookeeper-3.9.3-bin

$ tar -xf apache-zookeeper-3.9.3-bin.tar.gz -C /opt/
Optional: Create a symbolic link of the ZooKeeper installation folder:
$ ln -s /opt/apache-zookeeper-3.9.3-bin/ /opt/zookeeper
Change the folders permissions (if needed):
$ chmod -R 755 /opt/apache-zookeeper-3.9.3-bin/ $ sudo chown -R mtitek:mtitek /opt/apache-zookeeper-3.9.3-bin/ $ sudo chown -R mtitek:mtitek /opt/zookeeper

• Create the folder "data": "/opt/zookeeper/data"
  $ mkdir /opt/zookeeper/data
  
• Create the folder "data-log": "/opt/zookeeper/data-log"
  $ mkdir /opt/zookeeper/data-log
  
• Create the log folder: "/opt/zookeeper/logs"
  $ mkdir /opt/zookeeper/logs
  
• Copy the file "/opt/zookeeper/conf/zoo_sample.cfg" to "/opt/zookeeper/conf/zoo.cfg"
  $ cp /opt/zookeeper/conf/zoo_sample.cfg /opt/zookeeper/conf/zoo.cfg
  
• Define the property "dataDir" in the file "/opt/zookeeper/conf/zoo.cfg": dataDir=/opt/zookeeper/data
  
  
• Define the property "dataLogDir" in the file "/opt/zookeeper/conf/zoo.cfg": dataLogDir=/opt/zookeeper/data-log
  
  

Make sure that the directories and the files are created and updated using the user that will run ZooKeeper (you can also use: sudo -u mtitek mkdir data).

Example: ZooKeeper configuration file "zoo.cfg"
# The number of milliseconds of each tick. tickTime=2000 # The number of ticks that the initial synchronization phase can take. initLimit=10 # The number of ticks that can pass between sending a request and getting an acknowledgement. syncLimit=5 # The port at which the clients will connect. clientPort=2181 # The port address at which the clients will connect. clientPortAddress=0.0.0.0 # The directory where the snapshot data is stored. dataDir=/opt/zookeeper/data # The directory the transaction log of updates is stored. dataLogDir=/opt/zookeeper/data-log
Notes:

• If you run ZooKeeper in a cluster mode, the clientPort and clientPortAddress configuration parameters should be part of the ZooKeeper instances configuration (see Installation - ZooKeeper Cluster).
  
  
• (On Windows) if not already the case, you have to double-quote the path "%JAVA_HOME%"\bin\java.exe in the file "%ZK_HOME%\bin\zkEnv.cmd"
  
  
• (On Windows) if not already the case, you have to double-quote the path "%JAVA%" in the file "%ZK_HOME%\bin\zkServer.cmd"
  

Other configuration you might want to setup in file "zoo.cfg"
# The maximum number of client connections. Increase this if you need to handle more clients. maxClientCnxns=60 # The number of snapshots to retain in dataDir. autopurge.snapRetainCount=3 # Purge task interval in hours. Set to "0" to disable auto purge feature. autopurge.purgeInterval=1
You can optionally configure the JAVA_HOME environment variable:
$ vi /opt/zookeeper/conf/java.env export JAVA_HOME=/opt/jdk-23.0.2

Start ZooKeeper:
$ /opt/zookeeper/bin/zkServer.sh start
Stop ZooKeeper:
$ /opt/zookeeper/bin/zkServer.sh stop
Notes:

• By default ZooKeeper will try to use the configuration file found in "/opt/zookeeper/conf/zoo.cfg"
  
  
• You can specify a custom configuration file by posting its path after the "start" and "stop" parameters:
  $ /opt/zookeeper/bin/zkServer.sh start "/opt/zookeeper/conf/zoo_custom.cfg" $ /opt/zookeeper/bin/zkServer.sh stop "/opt/zookeeper/conf/zoo_custom.cfg"
  
• You can specify a custom configuration folder by using the option "--config" before the "start" and "stop" parameters:
  $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_custom" start $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_custom" stop