[CentOS] Network Installation of CentOS disk image via PXE

Sat Feb 9 15:14:00 UTC 2008
David G. Miller <dave at davenjudy.org>

"vincenzo romero" <new2xen at gmail.com> wrote:

> Hello all,
>
> I've deployed new servers - installing new CentOS servers via PXE
> booting using its iso distribution stored on an NFS server.  For
> certain server types;  I'd like to install custom applications into a
> server and then generate an image of that server, and deploy again via
> PXE to another group of servers.
>
> Wanted to find out if anyone can forward any pointers to papers or links on:
>
> 1.  Best and (cheapest) way to create disk image (that can be used for
> over the network installation over PXE) of an existing CentOS server
> with all its custom apps and packages ... would this be dd?  would
> this take a long time?
>
> 2.  Would like to find out if you can point me to a guide or doc -
> that specifically describes this process;  most PXE install notes out
> there describe the PXE config setup and assumes an ISO image (to
> create a new server), as opposed to deploying a "ghosted" image of an
> existing server.
>
> 3.  In a deployment of a "ghosted" image - would the DHCP
> automatically request for a new IP address upon completion of the
> installation on the target machine (since when I ghost the source
> machine, the network information will contain that source's machine IP
> address, MAC, etc. etc.)
Unfortunately, I can't give you full details on this.  We did something 
very similar to what you're asking about in #1 and #2 where I used to 
work.  I used the setup for installing on systems but someone else did 
the initial setup.  You need to look at two things: PXE and custom 
kickstart.  I think Red Hat has some guidance on how to set up both.  If 
not, Google.

The idea is that the system that needs to get an installation is set to 
"boot from LAN" in the BIOS and the PXE server is also setup as a DHCP 
server on the same LAN segment.  The system being installed does a 
normal boot from LAN which contacts the DHCP/PXE server.  The DHCP/PXE 
server provides the boot image using tftp from the first install CD and 
a kickstart file.  The kickstart file controls the installation as to 
which apps get installed.  The setup we used let us pick from several 
different possible kickstart files for different configurations so 
there's room for customizing the process.

Hopefully, that's enough of a start in the right direction that you can 
Google for the details.

As to #3, the idea is to have the source of the ghost image setup for 
DHCP booting and not be bound to a particular network card (HWADDR in 
the ifcfg-ethX file).  The target system gets the ghost image and then 
needs to reboot.  When it boots, it gets a new IP address via DHCP.

Cheers,
Dave

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