How to install Zookeeper

How to install Zookeeper

Download Zookeeper

Go to http://www.apache.org/dyn/closer.cgi/zookeeper/ and select a mirror. Go to stable folder and download the tar.gz file.

Here I am using wget to download the tar.gz file

wget http://apache.cs.utah.edu/zookeeper/stable/zookeeper-3.4.8.tar.gz

tar -xvzf zookeeper-3.4.8.tar.gz

ln -s zookeeper-3.4.8 zk

export ZK_HOME=/scratch/softwares/zk

Create config file: 

Zookeeper  ships a sample config file. Make a copy of the file and edit dataDir parameters.

cd zk/conf
 cp zoo_sample.cfg zoo.cfg

By default dataDir points to dataDir=/tmp/zookeeper, change it to something like /scratch/softwares/zookeeper

eg:
dataDir=/scratch/softwares/zookeeper

Install JDK

Make sure java is installed and JAVA_HOME env variable is set.

java -version
echo $JAVA_HOME
/scratch//softwares/jdk1.7.0_04

Add zookeeper bin folder to PATH, so that zookeeper commands can be executed without navigating to the zk/bin folder.

 cd ../bin
 export PATH=$PATH:/scratch/softwares/zk/bin

Start zookeeper

zkServer.sh start

 ZooKeeper JMX enabled by default
Using config: /scratch//softwares/zk/conf/zoo.cfg
Starting zookeeper ... STARTED

 Stop Zookeeper

zkServer.sh stop

ZooKeeper JMX enabled by default
Using config: /scratch//softwares/zk/conf/zoo.cfg
Stopping zookeeper ... STOPPED

 zkServer.sh status

ZooKeeper JMX enabled by default
Using config: /scratch//softwares/zk/conf/zoo.cfg
Mode: standalone


By default zookeeper is started in background. To start zookeeper in fore-ground use below command:

 zkServer.sh start-foreground

 This options helps to see what is going on with the server.

Start Zookeeper Client

export PATH=$PATH:/scratch/softwares/zk/bin

bash-3.2$ zkCli.sh

Connecting to localhost:2181
2016-06-18 23:06:25,928 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.8--1, built on 02/06/2016 03:18 GMT
2016-06-18 23:06:25,931

....

2016-06-18 23:06:25,935 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@291fffa9
2016-06-18 23:06:25,964 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost.localdomain/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
Welcome to ZooKeeper!
2016-06-18 23:06:25,969 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@876] - Socket connection established to localhost.localdomain/127.0.0.1:2181, initiating session
JLine support is enabled
2016-06-18 23:06:26,012 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@1299] - Session establishment complete on server localhost.localdomain/127.0.0.1:2181, sessionid = 0x1556495578b0000, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0]

 

create /testnode ""
Created /testnode

[zk: localhost:2181(CONNECTED) 5] ls /
[testnode, zookeeper]

 [zk: localhost:2181(CONNECTED) 6]  stat /testnode

cZxid = 0x2

ctime = Sat Jun 18 23:09:11 IST 2016

mZxid = 0x2

mtime = Sat Jun 18 23:09:11 IST 2016

pZxid = 0x2

cversion = 0

dataVersion = 0

aclVersion = 0

ephemeralOwner = 0x0

dataLength = 0

numChildren = 0