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Hi can't seem to change the hostname on my centos 6.5 host. I am following the instructions I found here: http://www.rackspace.com/knowledge_center/article/centos-hostname-change

I set my /etc/hosts like so ...

    [root@mig-dev-006 ~]# cat /etc/hosts
    127.0.0.1   localhost localhost.localdomain 
    192.168.32.128  ost-dev-00.domain.com ost-dev-00
    192.168.32.129  ost-dev-01.domain.com ost-dev-01

... then I make my /etc/sysconfig/network file like so ...

    [root@mig-dev-006 ~]# cat /etc/sysconfig/network
    NETWORKING=yes
    HOSTNAME=ost-dev-00.domain.com
    NTPSERVERARGS=iburst

... then I run hostname like so ...

    [root@mig-dev-006 ~]# hostname ost-dev-00.domain.com

... and then I run bash and all seems well ...

    [root@mig-dev-006 ~]# bash

... but when I restart my network the old hostname comes back:

    [root@ost-dev-00 ~]# /etc/init.d/network restart
    Shutting down interface eth0:  Device state: 3 (disconnected)
                                                               [  OK  ]
    Shutting down loopback interface:                          [  OK  ]
    Bringing up loopback interface:                            [  OK  ]
    Bringing up interface eth0:  Active connection state: activating
    Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/6
    state: activated
    Connection activated
                                                               [  OK  ]
    [root@ost-dev-00 ~]# bash
    [root@mig-dev-006 ~]# 

... I can't figure it out. What am I doing wrong here.

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1  
Have you edited your /etc/hostname file? –  Anthon Jul 17 '14 at 5:54
    
There isn't a /etc/hostname file. [root@smp-mig-dev-006 ~]# ls -l /etc/hostname outputs ls: cannot access /etc/hostname: No such file or directory –  Red Cricket Jul 17 '14 at 5:56
    
Might be a Centos thing. What does your manpage tell you about the permanency of hostname somename, that it has a lasting effect? (if not why do you make that call?) –  Anthon Jul 17 '14 at 5:59
    
I think /etc/hostname is in CentOS 7 but not in CentOS 6. –  Pavel Šimerda Jan 4 at 9:21
    
I realize this is old, but I smell NetworkManager at work, either that or you may have HOSTNAME= set in another file than network (ie, in network-scripts). The /etc/hostname file is not used in CentOS 6 (it's a systemd thing; that means CentOS 7 and up). Check the contents of the /etc/sysconfig/network-scripts/ifcfg-eth0 file; what is in it? Note: If you look at Redhat's if_post script in network-scripts/, you will see that set_hostname simply runs "hostname $HOSTNAME", where HOSTNAME is a shell variable set either in the network file or the ifcfg-eth0 file. –  Mike S Apr 30 at 18:12

5 Answers 5

up vote 21 down vote accepted

to change the hostname permanently, you need to change it in two places:

vi /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=newHostName

and:

vi /etc/hosts
127.0.0.1 newHostName
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

and then rebooting the system

share|improve this answer
1  
At the end of this two changes add hostname newHostName, is not necessary to reboot I think –  Edakos Sep 19 '14 at 21:01
2  
Editing the /etc/hosts file does not seem to be required –  jgritty Dec 12 '14 at 21:09
2  
That's exactly how I arrived at my conclusion :) –  jgritty Dec 13 '14 at 17:43
1  
The answer has been accepted, but first, /etc/hosts change is there only to make the hostname resolvable, not to change it, and /etc/sysconfig/network looks the same as in OP. Can anyone explain what exactly OP needed to change to make it work? –  Pavel Šimerda Jan 4 at 9:24
1  
I think a correct answer should work as an answer to the question. Repeating data from the question is good as long as the answer says the OP configured it correctly but didn't perform actions needed to load the new configuration (e.g. reboot). –  Pavel Šimerda Jan 4 at 12:46

A solution for centOS7 can be found here:

change hostname centOS7

hostnamectl set-hostname <new hostname>
share|improve this answer
1  
I'm liking centos7! –  Red Cricket Feb 3 at 7:02

If changing /etc/sysconfig/network and /etc/hosts does not change your screen name, do the following.

When you login, you see your screen name:

[john@oldhostname ~]

See what the current hostname is: oldhostname.olddomain.com. Then change the hostname to newhostname.newdomain.com. Then logout and login.

hostname

This returns: oldhostname.olddomain.com

hostname newhostname.newdomain.com

You won't see this reflected in your bash terminal. You have to logout and login again.

[john@newhostname ~]
share|improve this answer
    
This won't make a permanent change at all. –  Pavel Šimerda Jan 4 at 9:25
    
Thank you for your reply :) –  Red Cricket Feb 3 at 7:05

You can change your hostname with a single command.

  • Command: hostname - this displays old hostname
  • Command: hostname <new name> -this sets new hostname

Example

$ hostname mynewhost

For video help

share|improve this answer
    
Thank you for your reply :) –  Red Cricket Feb 3 at 7:04

I had to do this for a bunch of machines. Here is a simple python script to help you out. Simply provide the name of the new host as the first argument to the script.

for example: if you name the script changeHost.py then run it as

changeHost.py [NewHostName]

where NewHostName is your desired host name.

Also make sure to run this script as root.



#!/usr/bin/env python
import os

from sys import argv
script, newHostName = argv

print "Modifying network file..."
target = open("/etc/sysconfig/network","w")
target.truncate()
target.write("NETWORKING=yes\n")
target.write("HOSTNAME=")
target.write(newHostName)
target.write("\n")
target.close()

print "Modifying hosts file..."
target = open("/etc/hosts","w")
target.truncate()
target.write("127.0.0.1 ")
target.write(newHostName)
target.write(" localhost.localdomain localhosts\n")
target.close()

print "Set new hostname to %r" % newHostName
os.system('/bin/hostname ' + newHostName)
share|improve this answer
    
Hmm that's an ugly script. I wonder if Puppet would be a better tool for dealing with hostname. –  Red Cricket Jan 4 at 7:32
1  
    
Whoa! What's ansible? Sounds awesome. –  Red Cricket Feb 3 at 7:04
1  
This script is about 3 times as long as it needs to be. Python is the wrong tool for the job. A bash script would be much shorter, more readable, and more maintainable. –  Mike S Apr 30 at 18:59

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