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

You should replace mtitek:mtitek with your actual user/group names.

• 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