Hostname and IP address during kickstart

[Ryan Golhar]

I'm sorry.  I should take my time when writing messages.

My DHCP server has static entries for this group of machines (both name
and IP address).  When I source /etc/sysconfig/network, $HOSTNAME is
set.  I then use host to lookup the IP address (not hostname).  I script
is:

Source /etc/sysconfig/network
IPADDR=`host $HOSTNAME | cut -f 4 -d ' '`
echo ...

Ryan


-----Original Message-----
From: Pete Nesbitt [mailto:pete at linux1.ca] 
Sent: Thursday, July 15, 2004 9:32 AM
To: golharam at umdnj.edu; General Red Hat Linux discussion list
Subject: Re: Hostname and IP address during kickstart


On July 15, 2004 06:07 am, Ryan Golhar wrote:
> Hi Peter,
>
> Yes, that's almost exactly what I have.  It looks like the machine 
> name is set to $HOSTNAME.  I'm retrieving the IP address from 
> /etc/sysconfig/network.  I came up with this.  I need to add the the 
> full name to the list.
>
> Source /etc/sysconfig/network
> IPADDR=`hostname $HOSTNAME | cut -f 4 -d ' '`
> echo "127.0.0.1         localhost.localdomain   localhost" >
/etc/hosts
> echo "$IPADDR           $HOSTNAME.umdnj.edu     $HOSTNAME" >>
/etc/hosts
>
>
> -----
> Ryan Golhar
> Computational Biologist
> The Informatics Institute at
> The University of Medicine & Dentistry of NJ
>
> Phone: 973-972-5034
> Fax: 973-972-7412
> Email: golharam at umdnj.edu


Ryan,
If you want to use $HOSTNAME, look at 'man hostname' it has a -f and -s
option 
for short or long (fqdn) option.

I don't see how "IPADDR=`hostname $HOSTNAME | cut -f 4 -d ' '`" works,
that 
not going to give you an IP address.

Also, how are you getting an IP ftrom /etc/sysconfig/network,if it's
dhcp, 
there should be no IP address in there (nor is it going to be in  
/etc/sysconfig/network-scripts/ifcfg-eth0)

Pete

>
> -----Original Message-----
> From: Pete Nesbitt [mailto:pete at linux1.ca]
> Sent: Wednesday, July 14, 2004 10:54 PM
> To: golharam at umdnj.edu; General Red Hat Linux discussion list
> Subject: Re: Hostname and IP address during kickstart
>
> On July 14, 2004 09:30 am, Ryan Golhar wrote:
> > I have a bunch of machines that I kickstart.  They all use DHCP to 
> > obtain their hostname and IP address.  The names are address are all

> > static (in dhcpd.conf).
> >
> > Currently, in /etc/hosts on these machines, their hostname is set to

> > 127.0.0.1 and this interferes with PVM.  I need to set their host 
> > name
> >
> > to their correct IP address in /etc/hosts.  What is the easiest way 
> > of
> >
> > doing this during %post in kickstart?
> >
> > Ryan
>
> Hi Ryan,
> Here is a little shell script that will overwrite the existing 
> /etc/hosts file with the new IP/hostname (as well as 127...). I have 
> tested it in a dummy
> file. It needs to be run as root.
>
> If you have static entries, you need to add them into the script or 
> you will lose them.
>
>
> #!/bin/bash
> # this ONLY WORKS IF there are no other entries in hosts!!
> # it will overwrite anything in the hosts file!
>
> HOSTS="/etc/hosts"
> TEMP_HOSTS="/tmp/hosts.tmp"
> NIC="eth0"
> IP="`ifconfig $NIC | grep inet | cut -d : -f 2 | cut -d \  -f 1`" 
> FULL_NAME="`uname -n`" SHORT_NAME="`uname -n|cut -d. -f1`"
>
> echo "127.0.0.1 localhost.localdomain   localhost" > $TEMP_HOSTS
> echo "$IP       $FULL_NAME      $SHORT_NAME" >> $TEMP_HOSTS
> # add more static entries if needed like this:
> #echo "xxx.xxx.xxx.xxx	somehost.domain.com	somehost" >>
$TEMP_HOSTS
>
> cat $TEMP_HOSTS > $HOSTS
> #end
>
> Hope that helps
> --
> Pete Nesbitt, rhce

-- 
Pete Nesbitt, rhce