Linux change hostame

Check the hostname:

[root@node1 ~]# hostname
node1


As we can see in our case the hostname is node1.

We want to change it to node1.oracle.com

Open the file /etc/sysconfig/network and change the value of  HOSTNAME parameter:

[root@node1 ~]# gedit /etc/sysconfig/network

NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=node1.oracle.com
GATEWAY=192.165.2.105

Finally open the /etc/hosts file and make the proper changes

[root@node1 ~]# gedit /etc/hosts

The initial values

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1        node1 localhost.localdomain localhost
::1        localhost6.localdomain6 localhost6

The new values

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1    localhost.localdomain localhost
::1        localhost6.localdomain6 localhost6
192.165.2.105    node1.oracle.com    node1

Save the file and restart you system.

Check the hostname again:

root@node1 ~]# hostname
node1.oracle.com