Archive for the ‘Tutorial’ Tag

Getting started with HBase

There are quite a few HBase tutorials out there, but the reason I wanted to add another one was for two specific reasons:
1. To document the installation steps (HBase stand-alone mode) for my ready reference in future
2. To highlight the installation issues I faced and how I got around them so that anyone else facing the same can benefit.

Installation Steps

Download and install the latest version of Ubuntu from http://www.ubuntu.com/download

In my case I downloaded and installed Ubuntu 12.04.1 64-bit i.e. ubuntu-12.04.1-desktop-amd64.iso

Download and install Java SDK from http://www.oracle.com/technetwork/java/javase/downloads/index.html

Since Cloudera recommends JDK version 1.6.0_31 (https://ccp.cloudera.com/display/CDH4DOC/Java+Development+Kit+Installation)
I downloaded the same and installed it as follows:

root@ubuntu:~# mkdir /opt/java
root@ubuntu:~# cd /opt/java/
root@ubuntu:/opt/java# chmod +x jdk-6u31-linux-x64.bin 
root@ubuntu:/opt/java# ./jdk-6u31-linux-x64.bin 
... ... ... ...
... ... ... ...
root@ubuntu:/opt/java#
root@ubuntu:/opt/java# ls -lth jdk1.6.0_31/
total 19M
-r--r--r--  1 root root 4.7K Oct  6 14:32 register_zh_CN.html
-r--r--r--  1 root root 5.1K Oct  6 14:32 register.html
-r--r--r--  1 root root 6.5K Oct  6 14:32 register_ja.html
drwxr-xr-x  7 root root 4.0K Oct  6 14:32 jre
drwxr-xr-x  3 root root 4.0K Oct  6 14:32 lib
drwxr-xr-x  7 root root 4.0K Jan 20  2012 db
drwxr-xr-x  3 root root 4.0K Jan 20  2012 include
drwxr-xr-x  9 root root 4.0K Jan 20  2012 sample
drwxr-xr-x 10 root root 4.0K Jan 20  2012 demo
drwxr-xr-x  4 root root 4.0K Jan 20  2012 man
drwxr-xr-x  2 root root 4.0K Jan 20  2012 bin
-r--r--r--  1 root root 3.3K Jan 20  2012 COPYRIGHT
-r--r--r--  1 root root   40 Jan 20  2012 LICENSE
-r--r--r--  1 root root  115 Jan 20  2012 README.html
-r--r--r--  1 root root 165K Jan 20  2012 THIRDPARTYLICENSEREADME.txt
-rw-r--r--  1 root root  19M Jan 20  2012 src.zip
root@ubuntu:/opt/java# 

Set the JAVA_HOME environment variable

root@ubuntu:~# echo $JAVA_HOME
root@ubuntu:~#
root@ubuntu:~# vi .bashrc 

Add the following lines, save and exit:

export JAVA_HOME=/opt/java/jdk1.6.0_31
export PATH=$JAVA_HOME/bin:$PATH

Check

root@ubuntu:~# source .bashrc 
root@ubuntu:~# echo $JAVA_HOME
/opt/java/jdk1.6.0_31

root@ubuntu:~#
root@ubuntu:~# java -version
java version "1.6.0_31"
Java(TM) SE Runtime Environment (build 1.6.0_31-b04)
Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode)
root@ubuntu:~# 

Configure the CDH repositories

root@ubuntu:~# mkdir /opt/hbase
root@ubuntu:~# cd /opt/hbase/

Download http://archive.cloudera.com/cdh4/one-clickinstall/precise/amd64/cdh4-repository_1.0_all.deb into /opt/hbase

root@ubuntu:/opt/hbase# ls -lth
total 4.0K
-rw-r--r-- 1 root root 3.3K Oct  6 14:38 cdh4-repository_1.0_all.deb
root@ubuntu:/opt/hbase# 
root@ubuntu:/opt/hbase# sudo dpkg -i cdh4-repository_1.0_all.deb 
Selecting previously unselected package cdh4-repository.
(Reading database ... 140999 files and directories currently installed.)
Unpacking cdh4-repository (from cdh4-repository_1.0_all.deb) ...
Setting up cdh4-repository (1.0) ...
gpg: keyring `/etc/apt/secring.gpg' created
gpg: keyring `/etc/apt/trusted.gpg.d/cloudera-cdh4.gpg' created
gpg: key 02A818DD: public key "Cloudera Apt Repository" imported
gpg: Total number processed: 1
gpg:               imported: 1
root@ubuntu:/opt/hbase# 

Install HBase

root@ubuntu:/opt/hbase# sudo apt-get update
Ign http://archive.cloudera.com precise-cdh4 InRelease                                                          
Ign http://security.ubuntu.com precise-security InRelease                                                       
Ign http://extras.ubuntu.com precise InRelease                                                                  
Get:1 http://archive.cloudera.com precise-cdh4 Release.gpg [198 B]                                  
Ign http://us.archive.ubuntu.com precise InRelease                                               
Ign http://us.archive.ubuntu.com precise-updates InRelease           
Ign http://us.archive.ubuntu.com precise-backports InRelease         
Hit http://extras.ubuntu.com precise Release.gpg                     
Hit http://security.ubuntu.com precise-security Release.gpg          
Get:2 http://archive.cloudera.com precise-cdh4 Release [1,682 B]     
Hit http://us.archive.ubuntu.com precise Release.gpg                                                   
Hit http://extras.ubuntu.com precise Release                                                
Hit http://security.ubuntu.com precise-security Release                                      
Get:3 http://archive.cloudera.com precise-cdh4/contrib Sources [6,382 B]                     
Hit http://us.archive.ubuntu.com precise-updates Release.gpg                                          
Hit http://us.archive.ubuntu.com precise-backports Release.gpg                              
Hit http://extras.ubuntu.com precise/main Sources                                           
Get:4 http://archive.cloudera.com precise-cdh4/contrib amd64 Packages [16.8 kB]             
Hit http://security.ubuntu.com precise-security/main Sources                                          
Hit http://us.archive.ubuntu.com precise Release                                                      
Ign http://archive.cloudera.com precise-cdh4/contrib TranslationIndex                                           
Hit http://extras.ubuntu.com precise/main amd64 Packages                                    
Hit http://extras.ubuntu.com precise/main i386 Packages                                     
Hit http://us.archive.ubuntu.com precise-updates Release                                                        
Ign http://extras.ubuntu.com precise/main TranslationIndex                                                      
Hit http://us.archive.ubuntu.com precise-backports Release                                                      
Ign http://archive.cloudera.com precise-cdh4/contrib Translation-en_US                                          
Ign http://archive.cloudera.com precise-cdh4/contrib Translation-en                         
Ign http://extras.ubuntu.com precise/main Translation-en_US                                                     
Ign http://extras.ubuntu.com precise/main Translation-en                                                        
Hit http://us.archive.ubuntu.com precise/main Sources                                                           
Hit http://us.archive.ubuntu.com precise/restricted Sources                                                     
Hit http://us.archive.ubuntu.com precise/universe Sources                                                       
Hit http://us.archive.ubuntu.com precise/multiverse Sources                                                     
Hit http://us.archive.ubuntu.com precise/main amd64 Packages                                                    
Hit http://security.ubuntu.com precise-security/restricted Sources                                              
Hit http://security.ubuntu.com precise-security/universe Sources                                                
Hit http://us.archive.ubuntu.com precise/restricted amd64 Packages                                              
Hit http://security.ubuntu.com precise-security/multiverse Sources                                              
Hit http://security.ubuntu.com precise-security/main amd64 Packages                                             
Hit http://security.ubuntu.com precise-security/restricted amd64 Packages                                       
Hit http://security.ubuntu.com precise-security/universe amd64 Packages                                         
Hit http://us.archive.ubuntu.com precise/universe amd64 Packages                                                
Hit http://security.ubuntu.com precise-security/multiverse amd64 Packages                                       
Hit http://security.ubuntu.com precise-security/main i386 Packages                                              
Hit http://security.ubuntu.com precise-security/restricted i386 Packages                                        
Hit http://us.archive.ubuntu.com precise/multiverse amd64 Packages                                              
Hit http://security.ubuntu.com precise-security/universe i386 Packages                                          
Hit http://security.ubuntu.com precise-security/multiverse i386 Packages                                        
Hit http://security.ubuntu.com precise-security/main TranslationIndex                                           
Hit http://security.ubuntu.com precise-security/multiverse TranslationIndex                                     
Hit http://security.ubuntu.com precise-security/restricted TranslationIndex                                     
Hit http://security.ubuntu.com precise-security/universe TranslationIndex                                       
Hit http://us.archive.ubuntu.com precise/main i386 Packages                                                     
Hit http://security.ubuntu.com precise-security/main Translation-en                                             
Hit http://security.ubuntu.com precise-security/multiverse Translation-en                                       
Hit http://security.ubuntu.com precise-security/restricted Translation-en                                       
Hit http://us.archive.ubuntu.com precise/restricted i386 Packages                                               
Hit http://security.ubuntu.com precise-security/universe Translation-en                                         
Hit http://us.archive.ubuntu.com precise/universe i386 Packages                                                 
Hit http://us.archive.ubuntu.com precise/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise/main TranslationIndex
Hit http://us.archive.ubuntu.com precise/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/main Sources
Hit http://us.archive.ubuntu.com precise-updates/restricted Sources
Hit http://us.archive.ubuntu.com precise-updates/universe Sources
Hit http://us.archive.ubuntu.com precise-updates/multiverse Sources
Hit http://us.archive.ubuntu.com precise-updates/main amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/universe amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/multiverse amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/main i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/universe i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/main TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/main Sources
Hit http://us.archive.ubuntu.com precise-backports/restricted Sources
Hit http://us.archive.ubuntu.com precise-backports/universe Sources
Hit http://us.archive.ubuntu.com precise-backports/multiverse Sources
Hit http://us.archive.ubuntu.com precise-backports/main amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/universe amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/multiverse amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/main i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/universe i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/main TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise/main Translation-en
Hit http://us.archive.ubuntu.com precise/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise/restricted Translation-en
Hit http://us.archive.ubuntu.com precise/universe Translation-en
Hit http://us.archive.ubuntu.com precise-updates/main Translation-en
Hit http://us.archive.ubuntu.com precise-updates/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-updates/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-updates/universe Translation-en
Hit http://us.archive.ubuntu.com precise-backports/main Translation-en
Hit http://us.archive.ubuntu.com precise-backports/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-backports/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-backports/universe Translation-en
Fetched 25.1 kB in 30s (827 B/s)
Reading package lists... Done
root@ubuntu:/opt/hbase# 
root@ubuntu:/opt/hbase# sudo apt-get install hbase hbase-master
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  bigtop-jsvc bigtop-utils hadoop hadoop-hdfs libopts25 ntp zookeeper
Suggested packages:
  ntp-doc
The following NEW packages will be installed:
  bigtop-jsvc bigtop-utils hadoop hadoop-hdfs hbase hbase-master libopts25 ntp zookeeper
0 upgraded, 9 newly installed, 0 to remove and 119 not upgraded.
Need to get 70.1 MB of archives.
After this operation, 82.3 MB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Get:1 http://us.archive.ubuntu.com/ubuntu/ precise/main libopts25 amd64 1:5.12-0.1ubuntu1 [59.9 kB]
Get:2 http://us.archive.ubuntu.com/ubuntu/ precise-updates/main ntp amd64 1:4.2.6.p3+dfsg-1ubuntu3.1 [612 kB]
Get:3 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib bigtop-jsvc amd64 0.4+352-1.cdh4.1.0.p0.29~precise-cdh4.1.0 [53.2 kB]
Get:4 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib bigtop-utils all 0.4+352-1.cdh4.1.0.p0.28~precise-cdh4.1.0 [2,004 B]
Get:5 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib zookeeper all 3.4.3+25-1.cdh4.1.0.p0.28~precise-cdh4.1.0 [4,087 kB]
Get:6 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib hadoop all 2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0 [16.6 MB]
Get:7 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib hadoop-hdfs all 2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0 [12.7 MB]
Get:8 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib hbase all 0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0 [35.9 MB]
Get:9 http://archive.cloudera.com/cdh4/ubuntu/precise/amd64/cdh/ precise-cdh4/contrib hbase-master all 0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0 [19.2 kB]
Fetched 70.1 MB in 8min 41s (134 kB/s)                                                                          
Selecting previously unselected package libopts25.
(Reading database ... 141003 files and directories currently installed.)
Unpacking libopts25 (from .../libopts25_1%3a5.12-0.1ubuntu1_amd64.deb) ...
Selecting previously unselected package ntp.
Unpacking ntp (from .../ntp_1%3a4.2.6.p3+dfsg-1ubuntu3.1_amd64.deb) ...
Selecting previously unselected package bigtop-jsvc.
Unpacking bigtop-jsvc (from .../bigtop-jsvc_0.4+352-1.cdh4.1.0.p0.29~precise-cdh4.1.0_amd64.deb) ...
Selecting previously unselected package bigtop-utils.
Unpacking bigtop-utils (from .../bigtop-utils_0.4+352-1.cdh4.1.0.p0.28~precise-cdh4.1.0_all.deb) ...
Selecting previously unselected package zookeeper.
Unpacking zookeeper (from .../zookeeper_3.4.3+25-1.cdh4.1.0.p0.28~precise-cdh4.1.0_all.deb) ...
Selecting previously unselected package hadoop.
Unpacking hadoop (from .../hadoop_2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0_all.deb) ...
Selecting previously unselected package hadoop-hdfs.
Unpacking hadoop-hdfs (from .../hadoop-hdfs_2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0_all.deb) ...
Selecting previously unselected package hbase.
Unpacking hbase (from .../hbase_0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0_all.deb) ...
Selecting previously unselected package hbase-master.
Unpacking hbase-master (from .../hbase-master_0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0_all.deb) ...
Processing triggers for ureadahead ...
Processing triggers for man-db ...
Setting up libopts25 (1:5.12-0.1ubuntu1) ...
Setting up ntp (1:4.2.6.p3+dfsg-1ubuntu3.1) ...
 * Starting NTP server ntpd                                                                               [ OK ] 
Setting up bigtop-jsvc (0.4+352-1.cdh4.1.0.p0.29~precise-cdh4.1.0) ...
Setting up bigtop-utils (0.4+352-1.cdh4.1.0.p0.28~precise-cdh4.1.0) ...
Setting up zookeeper (3.4.3+25-1.cdh4.1.0.p0.28~precise-cdh4.1.0) ...
update-alternatives: using /etc/zookeeper/conf.dist to provide /etc/zookeeper/conf (zookeeper-conf) in auto mode.
Setting up hadoop (2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0) ...
update-alternatives: using /etc/hadoop/conf.empty to provide /etc/hadoop/conf (hadoop-conf) in auto mode.
Setting up hadoop-hdfs (2.0.0+541-1.cdh4.1.0.p0.27~precise-cdh4.1.0) ...
Setting up hbase (0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0) ...
update-alternatives: using /etc/hbase/conf.dist to provide /etc/hbase/conf (hbase-conf) in auto mode.
Setting up hbase-master (0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0) ...
Starting Hadoop HBase master daemon: +======================================================================+
|      Error: JAVA_HOME is not set and Java could not be found         |
+----------------------------------------------------------------------+
| Please download the latest Sun JDK from the Sun Java web site        |
|       > http://java.sun.com/javase/downloads/ <                      |
|                                                                      |
| HBase requires Java 1.6 or later.                                    |
| NOTE: This script will find Sun Java whether you install using the   |
|       binary or the RPM based installer.                             |
+======================================================================+
invoke-rc.d: initscript hbase-master, action &quot;start&quot; failed.
dpkg: error processing hbase-master (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for libc-bin ...
ldconfig deferred processing now taking place
Errors were encountered while processing:
 hbase-master
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@ubuntu:/opt/hbase# 

I got the above error the first time so I checked if JAVA_HOME is set properly.

root@ubuntu:/opt/hbase# echo $JAVA_HOME
/opt/java/jdk1.6.0_31

Since it seems ok, I decided to directly set JAVA_HOME in the hbase-master script

root@ubuntu:/opt/hbase# vi /etc/init.d/hbase-master

# Add this
export JAVA_HOME=/opt/java/jdk1.6.0_31

Lets try installing again

root@ubuntu:/opt/hbase# sudo apt-get install hbase hbase-master
Reading package lists... Done
Building dependency tree       
Reading state information... Done
hbase is already the newest version.
hbase-master is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 119 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? Y
Setting up hbase-master (0.92.1+154-1.cdh4.1.0.p0.23~precise-cdh4.1.0) ...
Starting Hadoop HBase master daemon: starting master, logging to /var/log/hbase/hbase-hbase-master-ubuntu.out
hbase-master.
root@ubuntu:/opt/hbase# 

This time everything went well.
View the list of HBase configuration files.

root@ubuntu:/opt/hbase# ls -lth /etc/hbase/conf/
total 28K
-rw-r--r-- 1 root root 1.1K Oct 30 12:06 hbase-site.xml
-rw-r--r-- 1 root root 2.3K Sep 29 11:54 hadoop-metrics.properties
-rw-r--r-- 1 root root 4.2K Sep 29 11:54 hbase-env.sh
-rw-r--r-- 1 root root 2.2K Sep 29 11:54 hbase-policy.xml
-rw-r--r-- 1 root root 2.5K Sep 29 11:54 log4j.properties
-rw-r--r-- 1 root root   10 Sep 29 11:54 regionservers
root@ubuntu:/opt/hbase# cat /etc/hbase/conf/regionservers
localhost
root@ubuntu:/opt/hbase#

Lets invoke the HBase shell and test.

root@ubuntu:/opt/hbase# hbase shell
12/10/06 15:07:20 WARN conf.Configuration: hadoop.native.lib is deprecated. Instead, use io.native.lib.available
HBase Shell; enter 'help' for list of supported commands.
Type "exit" to leave the HBase Shell
Version 0.92.1-cdh4.1.0, rUnknown, Sat Sep 29 11:55:59 PDT 2012

hbase(main):001:0> status
1 servers, 0 dead, 3.0000 average load

hbase(main):001:0> list
TABLE                                                                                                            
0 row(s) in 0.6370 seconds

hbase(main):002:0> 

hbase(main):002:0> create 'table1','cf1'


^Croot@ubuntu:/opt/hbase# 
root@ubuntu:/opt/hbase# 

Here I encountered the second issue. For some reason the HBase shell would hang.
After googling around for quite some time I found a fix.

Update the /etc/hosts file and ensure that there is no 127.0.1.1 that points to localhost and ubuntu
and comment out the ipv6 lines

root@ubuntu:/opt/hbase# vi /etc/hosts

192.168.38.137  hbase2

127.0.0.1       localhost ubuntu

# The following lines are desirable for IPv6 capable hosts
#::1     ip6-localhost ip6-loopback
#fe00::0 ip6-localnet
#ff00::0 ip6-mcastprefix
#ff02::1 ip6-allnodes
#ff02::2 ip6-allrouters

Also disable ipv6 as follows:

root@ubuntu:~# vi /etc/sysctl.conf 

and add the following lines to the end of it:

# Abhi: Disable ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

Now restart the system

root@ubuntu:/opt/hbase# /etc/init.d/hbase-master restart
Restarting Hadoop HBase master daemon: stopping master...
Starting Hadoop HBase master daemon: starting master, logging to /var/log/hbase/hbase-hbase-master-ubuntu.out
hbase-master.
root@ubuntu:/opt/hbase# 

Check if its running

root@ubuntu:/opt/hbase# jps
16353 Jps
15654 HMaster

Open the Hbase shell and lets play around with few commands

root@ubuntu:/opt/hbase# 
root@ubuntu:/opt/hbase# hbase shell
12/10/06 15:35:18 WARN conf.Configuration: hadoop.native.lib is deprecated. Instead, use io.native.lib.available
HBase Shell; enter 'help' for list of supported commands.
Type "exit" to leave the HBase Shell
Version 0.92.1-cdh4.1.0, rUnknown, Sat Sep 29 11:55:59 PDT 2012

hbase(main):007:0* list
TABLE                                                                                                            
0 row(s) in 0.0040 seconds

hbase(main):008:0> create 'table1','cf1'
0 row(s) in 1.0880 seconds

hbase(main):009:0> list
TABLE                                                                                                            
table1                                                                                                           
1 row(s) in 0.0160 seconds

hbase(main):010:0> scan 'table1'
ROW                           COLUMN+CELL                                                                        
0 row(s) in 0.0200 seconds

hbase(main):012:0> put 'table1','row1','cf1:greeting','Hello'
0 row(s) in 0.0590 seconds

hbase(main):013:0> put 'table1','row1','cf1:name','World'
0 row(s) in 0.0110 seconds

hbase(main):014:0> scan 'table1'
ROW                           COLUMN+CELL                                                                        
 row1                         column=cf1:greeting, timestamp=1349563833359, value=Hello                          
 row1                         column=cf1:name, timestamp=1349563858582, value=World                              
1 row(s) in 0.0350 seconds

hbase(main):016:0> get 'table1','row1'
COLUMN                        CELL                                                                               
 cf1:greeting                 timestamp=1349563833359, value=Hello                                               
 cf1:name                     timestamp=1349563858582, value=World                                               
2 row(s) in 0.0300 seconds

hbase(main):017:0> put 'table1','row2','cf1:greeting','Hi'
0 row(s) in 0.0140 seconds

hbase(main):018:0> put 'table1','row2','cf1:name','Abhi'
0 row(s) in 0.0080 seconds

hbase(main):019:0> scan 'table1'
ROW                           COLUMN+CELL                                                                        
 row1                         column=cf1:greeting, timestamp=1349563833359, value=Hello                          
 row1                         column=cf1:name, timestamp=1349563858582, value=World                              
 row2                         column=cf1:greeting, timestamp=1349563961204, value=Hi                             
 row2                         column=cf1:name, timestamp=1349563973437, value=Abhi                               
2 row(s) in 0.0730 seconds

hbase(main):020:0> get 'table1','row2'
COLUMN                        CELL                                                                               
 cf1:greeting                 timestamp=1349563961204, value=Hi                                                  
 cf1:name                     timestamp=1349563973437, value=Abhi                                                
2 row(s) in 0.0080 seconds

hbase(main):021:0> 

You can open a browser and go to http://localhost:60010/ to access the HBase monitoring WebUI

HBase WebUI

Updated on October 31, 2012
Note: I have changed the hostname of my system from ‘ubuntu’ to ‘hbase2’

Set the HBase Root Directory

Although we are able to play around with HBase – create tables, put and get data etc. the data will get deleted once we restart the system as it is transient. In the stand-alone mode everything is executed within a single Java process and the data/files get stored under /tmp by default. Most OS clear /tmp on reboot thereby removing all the data. To make the data persistent we need to edit the hbase-site.xml file and set the root directory.

abhi@hbase2:~$ sudo mkdir /opt/hbase/data/
abhi@hbase2:~$ sudo chown -cRvf hbase:users /opt/hbase/data/
abhi@hbase2:~$ ls -lth /opt/hbase/
total 8.0K
drwxr-xr-x 7 hbase users 4.0K Oct 30 12:47 data
abhi@hbase2:~$
abhi@hbase2:~$ sudo vi /etc/hbase/conf/hbase-site.xml

<configuration>
    <property>
        <name>hbase.rootdir</name>
        <value>file:///opt/hbase/data</value>
    </property>
</configuration>

Restart hbase-master.

abhi@hbase2:~$ sudo /etc/init.d/hbase-master restart

Now when you create tables and enter data, the data will persist even after system restart.
Lets create a table and enter data.

hbase(main):005:0> create 'users','info'
0 row(s) in 1.1180 seconds

hbase(main):006:0> list
TABLE
users
1 row(s) in 0.0090 seconds

hbase(main):007:0> put 'users','abhi','info:name','abhishek'
0 row(s) in 0.0660 seconds

hbase(main):008:0> put 'users','abhi','info:age','30'
0 row(s) in 0.0110 seconds

hbase(main):009:0> scan 'users'
ROW                                         COLUMN+CELL
 abhi                                       column=info:age, timestamp=1351626512340, value=30
 abhi                                       column=info:name, timestamp=1351626501011, value=abhishek
1 row(s) in 0.0350 seconds

hbase(main):010:0> flush 'users'
0 row(s) in 0.0750 seconds

hbase(main):011:0>

Note: Always do a flush on your tables so that the data gets written as files in your filesystem.

In my next post we’ll see how HBase persists the data physically on the filesystem as files and directories.