Hi there, This blog is to help you for Apache Zookeeper installation on your local Ubuntu machine.

Apache Zookeeper is used to develop and maintain an open-source server which provides highly reliable distributed coordination. 

Follow these links to learn more about Apache Zookeeper.

• https://zookeeper.apache.org/
• https://zookeeper.apache.org/doc/trunk/
• https://zookeeper.apache.org/doc/trunk/zookeeperOver.html
• https://zookeeper.apache.org/doc/trunk/zookeeperStarted.html
• http://www.tutorialspoint.com/zookeeper/

Zookeeper was originally built by Yahoo and widely used by Apache Hadoop, Apache HBase,  Apache Solr and many more.

Java version greater then or equal to 1.6 is required for Zookeeper.

Steps to install Zookeeper
 

• Download a stable version of zookeeper from Apache mirrors
   
• Open terminal and go to that directory. (Suppose downloaded in Downloads)

cd ~/Downloads

• Extract the tar file

sudo tar -zxvf zookeeper-3.4.8.tar.gz

• Move the extracted package to /usr/local/zookeeper 

sudo mv ~/zookeeper-3.4.8 /usr/local/zookeeper

• Open your .bashrc. 

gedit ~/.bashrc

• Append the following code into it.

#zookeper variables
export ZOOKEEPER_HOME=/usr/local/zookeeper
export PATH=$ZOOKEEPER_HOME/bin:$PATH

• Save the .bashrc file
   
• Execute the source command to .bashrc.

source ~/.bashrc

• Go to Zookeeper's conf directory

cd /usr/local/zookeeper/conf

• Make a copy of zoo_sample.cfg with file name zoo.cfg

sudo cp zoo_sample.cfg zoo.cfg

• Open zoo.cfg

sudo gedit zoo.cfg

• Edit value for dataDir

dataDir=/home/avish/zookeeper/data

• Save the file.
   
• You need to manually create the location for dataDir, execute the below line for it.

mkdir ~/zookeeper/data

• now create an empty file inside it, and put a value 1 inside it.

touch ~/zookeeper/data/myid

sudo gedit ~/zookeeper/data/myid

• Again open your zoo.cfg file, and append the following line to it.

server.1=localhost:2888:3888

Now the Installation part is over you can start your Zookeeper server.
 

cd

zkServer.sh start

The response of above would be

ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

To use it in Command line mode 

zkCli.sh

And the response will be

Connecting to localhost:2181
2016-05-23 19:02:27,157 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.8--1, built on 02/06/2016 03:18 GMT
2016-05-23 19:02:27,160 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=localhost
2016-05-23 19:02:27,160 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.7.0_80
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Oracle Corporation
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=/usr/lib/jvm/java-7-oracle/jre
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=/usr/local/zookeeper/bin/../build/classes:/usr/local/zookeeper/bin/../build/lib/*.jar:/usr/local/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/usr/local/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/usr/local/zookeeper/bin/../lib/netty-3.7.0.Final.jar:/usr/local/zookeeper/bin/../lib/log4j-1.2.16.jar:/usr/local/zookeeper/bin/../lib/jline-0.9.94.jar:/usr/local/zookeeper/bin/../zookeeper-3.4.8.jar:/usr/local/zookeeper/bin/../src/java/lib/*.jar:/usr/local/zookeeper/bin/../conf:
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=/tmp
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Linux
2016-05-23 19:02:27,162 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=amd64
2016-05-23 19:02:27,163 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=3.13.0-58-generic
2016-05-23 19:02:27,163 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=abhishek
2016-05-23 19:02:27,163 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/home/abhishek
2016-05-23 19:02:27,163 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/home/abhishek
2016-05-23 19:02:27,164 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@6da13047
Welcome to ZooKeeper!
2016-05-23 19:02:27,195 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2016-05-23 19:02:27,199 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@876] - Socket connection established to localhost/127.0.0.1:2181, initiating session
JLine support is enabled
[zk: localhost:2181(CONNECTING) 0] 2016-05-23 19:02:27,306 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1299] - Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x154ddd08ab80000, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null

To know about the status of server

zkServer.sh status

And the response will be

ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/bin/../conf/zoo.cfg
Mode: standalone

To Stop the Zookeeper server

zkServer.sh stop

And the response would be

ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED