Apache Hadoop

INSTALLING HADOOP ON RHEL FEDORA CEntOS
-single node problem

Prerequisites:
#gedit /etc/hostname

change hostname to localhost

1. Installing  JAVA JDK check ver by

#yum provides java (or) rpm -qa | grep -e "JAVA"

2. Adding a dedicated Hadoop system user: You will need a user for hadoop system you will install.

To create a new user "huser" in a group called "supergroup", run the following commands in your
terminal:
from root
#sudo groupadd supergroup
#sudo adduser -G supergroup huser
#usermod -g wheel huser

3.Configuring SSH: install SSH server before, you can run the following command in your terminal:

By this command, you will have installed ssh server on your machine, the port is 22 by default.

#sudo yum install openssh* -y
-->We have installed SSH because Hadoop requires access to localhost (in case single node cluster) or communicates with remote nodes (in case multi-node cluster).<---

After this step, you will need to generate SSH key for huser (and the users you need to administer Hadoop if any) by running the following commands, but you need first to switch to huser:
#su huser
#ssh-keygen -t rsa -P ""

To be sure that SSH installation is went well, you can open a new terminal and try to create ssh session using huser
by the following command:

#ssh localhost


Disable IPv6: You will need to disable IP version 6 because Fedora is using 0.0.0.0 IP for different

SYSTEM CONFIGURATION

 -You will need to run the following commands using a root account:

#sudo gedit /etc/sysctl.conf

This command will open sysctl.conf in text editor, you can copy the following lines at the end of the
file:
#disable ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

check by

#sudo sysctl -p

To make sure that IPV6 is disabled, you can run the following command:
#cat /proc/sys/net/ipv6/conf/all/disdisable_ipv6

The printed value should be 1, which means that is disabled.