Syslinux - Aug 2015 - Looking for ways to save space - AKA how to boot multiple machines from the same root

Because everything I searched on for a PXELinux mailing list pointed me to here.
And because PXELinux is a derivative of SYSLinux. If there is a better mailing
list for my questions, please let me know.

 

Since you say its possible, care to enlighten me on how to do so?

 

Marc

 

From: Don Cupp [mailto:doncuppjr at yahoo.com] 
Sent: Tuesday, August 25, 2015 10:58 AM
To: Marc Tousignant <myrdhn at gmail.com>; syslinux at zytor.com
Subject: Re: [syslinux] Looking for ways to save space - AKA how to boot
multiple machines from the same root

 

Yes it is possible. Not sure why you posted this to syslinux though.

 

 

On Monday, August 24, 2015 10:46 PM, Marc Tousignant via Syslinux <syslinux
at zytor.com <mailto:syslinux at zytor.com> > wrote:

 

I have several machines, same hardware and config, but one tiny little
change.. the hostname. Each one of these diskless machines needs its own
hostname.

Presently my pxelinux.cfg is setup like:

prompt 1

default Gentoo

timeout 10



label Gentoo

kernel boot/kernel-3.16.5-gentoo

APPEND root=/dev/nfs rw ip=dhcp
nfsroot=192.168.1.10:/RAID/diskless/XXXXX-mythtv-0.27-fixes,tcp,rsize=131072
,wsize=131072,nfsvers=3

Where the XXXXX is the hostname. Because I have 3 of these machines I am
using up 3 times the disk space.

I am wondering if there is a way all 3 of them can run from the same
nfsroot, but somehow have different hostnames/machine-ids.

Presently the hostname comes from /RAID/diskless/XXXXX
-mythtv-0.27-fixes/etc/conf.d/hostname and the machine-id from
/RAID/diskless/XXXXX -mythtv-0.27-fixes/etc/machine-id and these are the
only 2 differing files from machine to machine.



Marc

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So while you maybe using pxelinux, and more generally the pxe protocol for
booting, your real challange is in the linux init process. That hostname file is
only really used during startup to set a system wide hostname variable. Your
chosen distro just happens to use a file with a static entry to do this. Other
distro's use network files compared against mac address's. There are a
bunch of ways to go about setting the hostname if your willing to dig into init.
You could even use pxelinux to pass a variable via the kernel cmd_line, but you
will likely need to alter your distro's init scripts to look for and utilize
that variable.
 


     On Tuesday, August 25, 2015 5:51 PM, Marc Tousignant <myrdhn at
gmail.com> wrote:
   

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{}#yiv8083307410 Because everything I searched on for a PXELinux mailing list
pointed me to here. And because PXELinux is a derivative of SYSLinux. If there
is a better mailing list for my questions, please let me know. ?Since you say
its possible, care to enlighten me on how to do so? ?Marc ?From: Don Cupp
[mailto:doncuppjr at yahoo.com]
Sent: Tuesday, August 25, 2015 10:58 AM
To: Marc Tousignant <myrdhn at gmail.com>; syslinux at zytor.com
Subject: Re: [syslinux] Looking for ways to save space - AKA how to boot
multiple machines from the same root ?Yes it is possible. Not sure why you
posted this to syslinux though. ? ?On Monday, August 24, 2015 10:46 PM, Marc
Tousignant via Syslinux <syslinux at zytor.com> wrote: ?I have several
machines, same hardware and config, but one tiny little
change.. the hostname. Each one of these diskless machines needs its own
hostname.

Presently my pxelinux.cfg is setup like:

prompt 1

default Gentoo

timeout 10



label Gentoo

kernel boot/kernel-3.16.5-gentoo

APPEND root=/dev/nfs rw ip=dhcp
nfsroot=192.168.1.10:/RAID/diskless/XXXXX-mythtv-0.27-fixes,tcp,rsize=131072
,wsize=131072,nfsvers=3

Where the XXXXX is the hostname. Because I have 3 of these machines I am
using up 3 times the disk space.

I am wondering if there is a way all 3 of them can run from the same
nfsroot, but somehow have different hostnames/machine-ids.

Presently the hostname comes from /RAID/diskless/XXXXX
-mythtv-0.27-fixes/etc/conf.d/hostname and the machine-id from
/RAID/diskless/XXXXX -mythtv-0.27-fixes/etc/machine-id and these are the
only 2 differing files from machine to machine.



Marc

_______________________________________________
Syslinux mailing list
Submissions to Syslinux at zytor.com
Unsubscribe or set options at:
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Marc Tousignant via Syslinux <syslinux at zytor.com> writes:
> Since you say its possible, care to enlighten me on how to do so?
You can set the hostname via DHCP, see for example
http://www.ingmarverheij.com/configure-hostname-via-dhcp/
-- 
Regards,
Feri.

Actually, I think I found the best way to do it, AUFS exported via NFS.
I'll still probably be exporting /RAID/diskless/XXXXX-mythtv-0.27-fixes
However that will probably be an AUFS mount point for my baseOS folder and
my XXXXX folder. Anything machine specific would go into XXXXX, like the
hostname file.
I'll probably do some testing with an actual system this weekend, but so far
nfs mounting a test folder seems to work like I need it to.

Marc

-----Original Message-----
From: Ferenc Wagner [mailto:wferi at niif.hu] 
Sent: Wednesday, August 26, 2015 2:32 PM
To: Marc Tousignant <myrdhn at gmail.com>
Cc: syslinux at zytor.com
Subject: Re: [syslinux] Looking for ways to save space - AKA how to boot
multiple machines from the same root

Marc Tousignant via Syslinux <syslinux at zytor.com> writes:
> Since you say its possible, care to enlighten me on how to do so?
You can set the hostname via DHCP, see for example
http://www.ingmarverheij.com/configure-hostname-via-dhcp/
--
Regards,
Feri.