Download Apache ZooKeeper "3.8.1" (choose a mirror site for your download): http://zookeeper.apache.org/releases.html

• Extract the file "apache-zookeeper-3.8.1-bin.tar.gz" in the folder you want to install ZooKeeper: /opt/apache-zookeeper-3.8.1-bin
  $ tar -xf apache-zookeeper-3.8.1-bin.tar.gz -C /opt/
  Create a symbolic link of the ZooKeeper installation folder:
  $ ln -s /opt/apache-zookeeper-3.8.1-bin/ /opt/zookeeper
  
• You need to create and configure multiple ZooKeeper configuration folders for each instance.
  
  
  • Create the data folders for each instance ("data_1", "data_2", "data_3"): $ mkdir /opt/zookeeper/data_1 $ mkdir /opt/zookeeper/data_2 $ mkdir /opt/zookeeper/data_3
    
  • Create the data log folders for each instance ("data-log_1", "data-log_2", "data-log_3"): $ mkdir /opt/zookeeper/data-log_1 $ mkdir /opt/zookeeper/data-log_2 $ mkdir /opt/zookeeper/data-log_3
    
  • Create the ZooKeeper logs folders for each instance ("logs_1", "logs_2", "logs_3"): $ mkdir /opt/zookeeper/logs_1 $ mkdir /opt/zookeeper/logs_2 $ mkdir /opt/zookeeper/logs_3
    
  • Create ZooKeeper configuration folders for each instance ("conf_1", "conf_2", "conf_3"):
    $ mkdir /opt/zookeeper/conf_1 $ mkdir /opt/zookeeper/conf_2 $ mkdir /opt/zookeeper/conf_3
    
  • Copy the content of the "conf/" folder to each configuration folder:
    $ cp /opt/zookeeper/conf/*.* /opt/zookeeper/conf_1 $ cp /opt/zookeeper/conf/*.* /opt/zookeeper/conf_2 $ cp /opt/zookeeper/conf/*.* /opt/zookeeper/conf_3
    
  • Create the configuration file "zoo.cfg" for each configuration folder:
    $ cp /opt/zookeeper/conf/zoo_sample.cfg /opt/zookeeper/conf_1/zoo.cfg $ cp /opt/zookeeper/conf/zoo_sample.cfg /opt/zookeeper/conf_2/zoo.cfg $ cp /opt/zookeeper/conf/zoo_sample.cfg /opt/zookeeper/conf_3/zoo.cfg
    
  • Initialize the server id for each ZooKeeper instance:
    $ echo "1" > /opt/zookeeper/data_1/myid $ echo "2" > /opt/zookeeper/data_2/myid $ echo "3" > /opt/zookeeper/data_3/myid
    
• For each of the configuration files ("conf_1/zoo.cfg", "conf_2/zoo.cfg", "conf_3/zoo.cfg"), you need to do the following:
  
  
  • Modify the properties "dataDir" and "dataLogDir":
    
    
    • First instance (conf_1/zoo.cfg):
      dataDir=/opt/zookeeper/data_1 dataLogDir=/opt/zookeeper/data-log_1
      
    • Second instance (conf_2/zoo.cfg):
      dataDir=/opt/zookeeper/data_2 dataLogDir=/opt/zookeeper/data-log_2
      
    • Third instance (conf_3/zoo.cfg):
      dataDir=/opt/zookeeper/data_3 dataLogDir=/opt/zookeeper/data-log_3
      
  • Add a static configuration for each ZooKeeper instance:
    server.1=localhost:2888:3888:participant;0.0.0.0:2181 server.2=localhost:2889:3889:participant;0.0.0.0:2182 server.3=localhost:2890:3890:participant;0.0.0.0:2183
    
  • Remove the properties "clientPort" and "clientPortAddress".
    You should not include these parameters in the ZooKeeper configuration "conf/zoo.cfg" file. They should be part of the ZooKeeper instances configuration (see above).
    
    
  • Because the default port is 8080 for the Jetty embedded server, You need to add the property "admin.serverPort" to override the default value. This allow each instance to have its unique port for AdminServer http interface.
    Reminder: this step is needed because we are configuring multiple ZooKeeper instances on the same host.
    
    
    • First instance ("conf_1/zoo.cfg"):
      admin.serverPort=8081
      
    • Second instance ("conf_2/zoo.cfg"):
      admin.serverPort=8082
      
    • Third instance ("conf_3/zoo.cfg"):
      admin.serverPort=8083
      
• For each instance, you will need to create the file "zookeeper-env.sh" to initialize the environment variables "ZOOCFGDIR" and "ZOO_LOG_DIR".
  
  
  • "/opt/zookeeper/conf_1/zookeeper-env.sh":
    $ echo "ZOOCFGDIR=/opt/zookeeper/conf_1" > /opt/zookeeper/conf_1/zookeeper-env.sh $ echo "ZOO_LOG_DIR=/opt/zookeeper/logs_1" >> /opt/zookeeper/conf_1/zookeeper-env.sh
    
  • "/opt/zookeeper/conf_2/zookeeper-env.sh":
    $ echo "ZOOCFGDIR=/opt/zookeeper/conf_2" > /opt/zookeeper/conf_2/zookeeper-env.sh $ echo "ZOO_LOG_DIR=/opt/zookeeper/logs_2" >> /opt/zookeeper/conf_2/zookeeper-env.sh
    
  • "/opt/zookeeper/conf_3/zookeeper-env.sh":
    $ echo "ZOOCFGDIR=/opt/zookeeper/conf_3" > /opt/zookeeper/conf_3/zookeeper-env.sh $ echo "ZOO_LOG_DIR=/opt/zookeeper/logs_3" >> /opt/zookeeper/conf_3/zookeeper-env.sh
    
• (On windows) I needed to modify the "%ZK_HOME%\bin\zkServer.cmd" file.
  I had to delete the "%ZOOCFG%" parameter from the line command.
  This way I was able to specify different ZooKeeper configuration files.
  Here's how it looks:
  call "%JAVA%" "-Dzookeeper.log.dir=%ZOO_LOG_DIR%" "-Dzookeeper.root.logger=%ZOO_LOG4J_PROP%" "-Dzookeeper.log.file=%ZOO_LOG_FILE%" "-XX:+HeapDumpOnOutOfMemoryError" "-XX:OnOutOfMemoryError=cmd /c taskkill /pid %%%%p /t /f" -cp "%CLASSPATH%" %ZOOMAIN% %*
  

Example: ZooKeeper configuration file "zoo.cfg":

/opt/zookeeper/conf_1/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 directory where the snapshot data is stored. dataDir=/opt/zookeeper/data_1 # The directory the transaction log of updates is stored. dataLogDir=/opt/zookeeper/data-log_1 # the port at which the clients will connect: 2181, 2182, 2183 # the port address at which the clients will connect: 0.0.0.0 server.1=localhost:2888:3888:participant;0.0.0.0:2181 server.2=localhost:2889:3889:participant;0.0.0.0:2182 server.3=localhost:2890:3890:participant;0.0.0.0:2183 # Jetty AdminServer http port admin.serverPort=8081
/opt/zookeeper/conf_2/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 directory where the snapshot data is stored. dataDir=/opt/zookeeper/data_2 # The directory the transaction log of updates is stored. dataLogDir=/opt/zookeeper/data-log_2 # the port at which the clients will connect: 2181, 2182, 2183 # the port address at which the clients will connect: 0.0.0.0 server.1=localhost:2888:3888:participant;0.0.0.0:2181 server.2=localhost:2889:3889:participant;0.0.0.0:2182 server.3=localhost:2890:3890:participant;0.0.0.0:2183 # Jetty AdminServer http port admin.serverPort=8082
/opt/zookeeper/conf_3/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 directory where the snapshot data is stored. dataDir=/opt/zookeeper/data_3 # The directory the transaction log of updates is stored. dataLogDir=/opt/zookeeper/data-log_3 # the port at which the clients will connect: 2181, 2182, 2183 # the port address at which the clients will connect: 0.0.0.0 server.1=localhost:2888:3888:participant;0.0.0.0:2181 server.2=localhost:2889:3889:participant;0.0.0.0:2182 server.3=localhost:2890:3890:participant;0.0.0.0:2183 # Jetty AdminServer http port admin.serverPort=8083

To start ZooKeeper instances:
$ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_1" start $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_2" start $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_3" start
To stop ZooKeeper instances:
$ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_1" stop $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_2" stop $ /opt/zookeeper/bin/zkServer.sh --config "/opt/zookeeper/conf_3" stop