[Beowulf] Problem while booting diskless node.

Maxime Kinet mkinet at ulb.ac.be
Wed May 2 08:11:20 PDT 2007

ok, I succeeded.
Thanks to all for helpfull comments.

Maxime Kinet
Université Libre de Bruxelles
Physique Statistique et Plasmas, CP 231
Campus Plaine - Boulevard du Triomphe,
1050 Bruxelles.

Tel.   : +32-2-650.59.08
e-mail : mkinet at ulb.ac.be

On 01 May 2007, at 12:34, Panagiotis Christopoulos wrote:

> On Monday 30 April 2007 13:04, Maxime Kinet wrote:
>> Hi,
>> I'm trying to set up my first cluster with diskless nodes. To achieve
>> that, I'm using PXElinux on a server, running Fedora Core 6, and a
>> NFS-mounted root partition on the node.
>> Everything works perfectly
>> (getting the IP address, loading the kernel and mounting the
>> filesytem) until the node has to run some binaries located into /sbin
>> during the boot process. Apparently it's unable to execute them
>> because they have been compiled with dynamically linked libraries and
>> not statically. The /sbin directory of the node is a simple copy of
>> the one of the server.
>  I suppose, that you have done something like, creating a /diskless  
> directory
> inside your nfs,tftp,dhcp etc... server, copying files(eg. /usr/* )  
> from the
> server, inside that /diskless dir with the same hierarchy, and this  
> resulted
> in a structure which would home, your nfs exported, root fs of your  
> nodes.
> I'm not an expert, but because you said about dynamic libraries, I  
> cannot
> understand, why this is a problem, you copied /sbin inside / 
> diskless, but you
> didn't copy /lib or /usr/lib? The problem with dynamic libraries,  
> starts
> because your /diskless does not have these libraries.
>> I tried to avoid the problem using the busybox
>> tools, and it worked a bit better but then it couldn't execute bash
>> scripts such as rc.sysinit.
> Have you created an init in your busybox, to chroot(exec  
> switch_root) inside
> your nfs root fs after mounting it?
>> As anybody ever encountered such problems and what should I do to
>> solve it? recompile the kernel of the node or of the server? change
>> the distribution? Are there any other simpler method to proceed than
>> using PXE?
> There are two things you can do. As Douglas Eadline said, it starts by
> thinking if you want to reinvent the wheel or not. If you have time,
> machines, if you know that your teachers won't get annoyed  and you  
> can work
> in a university lab, so you will not pay for the power supply  
> yourself:p
> continue with fedora and all these brainstorming things. You will  
> learn linux
> administration and propably you will do amazing things. If you  
> don't have
> time etc. the guys in warewulf, are doing the same job for about 7  
> years, and
> they provide you all this knowledge they gained, in a simple  
> installation
> process.
>   Back in the technical stuff, from your sayings, I think that  
> something is
> wrong with your /diskless dir(if you have one, of course). I cannot
> understand why you want to use busybox. We use busybox when why  
> want an
> initramfs to do specific jobs(such as unlocking  and mounting  
> encrypted
> partitions,yes, I know this is not the best example I could give)  
> before
> chrooting inside our real root fs and exec init as Mark Hahn said  
> or if we
> are running embedded. Also, I don't think that you have to change your
> distribution, and if you don't like PXE, you can see how the guys  
> in LTSP
> boot( I think they use both PXE and "etherboot" and you can make a  
> choice),
> but for me, syslinux is fine!
> This was my point of view, I hope I helped and if you want to ask  
> something,
> feel free to send me a mail, or of course, ask again in the list,
> Panagiotis Christopoulos
> System Administrator
> Technological Institute of Athens
> Department of Informatics

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