On Tue, 5 Feb 2008, Beyerle Urs wrote:

> Hi Jon,
>
> Jon Peatfield wrote:
>>  Many thanks for this!  I was just reading through the pxe booting stuff
>>  at:
>>
>>    http://linux.web.psi.ch/livecd/diskless.html
>>
>>  and thought I'd followed the instructions closely enough but kept getting
>>  the boot failing 'cos I'd used a hostname rather than an IP address in the
>>  nfsroot definition.  After that it worked like a charm.
>>
>>  I'm a little bit puzzled why a hostname doesn't work, by the time the
>>  mount is attempted the dhcp client has already obtained a list of
>>  nameservers and seems to have filled in resolv.conf.  Maybe the initrd
>>  environment just hasn't got support for DNS lookups.  I'll look more
>>  closely this afternoon but just thought I'd ask first...
>
> In the initrd environment I use busybox to mount nfs.
>
>>  livecd-2.7.4/linux-live.sl/initrd/static-binaries/busybox
> BusyBox v1.7.1 (2007-09-21 01:50:40 CEST) multi-call binary
>
> Some dhcp features are build in, but it seems that
>
> mount -t nfs -o nolock,ro,rsize=8192,wsize=8192,hard,intr $NFSROOT $DIR
>
> is not taking into account /etc/resolv.conf or it is not able to do a DNS 
> lookup. I haven't looked closer into the busybox source code so far...

Fair enough.  If I have any time I might try to work it out, I just 
thought I'd ask first.

Is there a simple way to add stuff into the initrd (or run an initrd like 
thing on a normal box) for debugging?

>>  When doing the nfsroot thing is there a good reason to keep everything in
>>  squashfs?  ie for testing a custom version can I arrange to just have a
>>  suitable plain sl (installed) tree nfs mountable by clients?  That will
>>  let me fairly easily tweak the set of packages and config until I'm ready
>>  to build a set of custom .iso files...
>
> You're right. Keeping everything in squashfs makes no sense in NFS mounted 
> environment. My idea was just to keep it simple - that means to have the same 
> build scripts for a LiveCD/DVD as for a NFS mounted Live System. Of course, 
> this is something I could put on the wish list of future livecd-build script 
> versions.
> Is anybody else interested in this "feature"?

Clearly having it in squashfs does save diskspace which isn't a 'bad' 
thing... :-)

>>  I'm considering making some custom local net-boot images - partly to
>>  test/diagnose machines (though the standard livecd seems to contains
>>  pretty much all one would need) and maybe to run some information displays
>>  (they just need to boot with a slightly weird X config and automatically
>>  run a web browser pointing at a suitable URL)...
>
> This should be quite simple just download the latest livecd build scripts 
> (livecd-2.7.4) and follow the description on 
> http://linux.web.psi.ch/livecd/build.html

I've started looking at that, and may feel brave enough to work through 
the setup soonish (if my boss will let me...:-)

>>  Obviously in such a setup one wouldn't want to nfs mount the nfsroot rw so
>>  it would still need some kind of unionfs/aufs magic (at least for things
>>  like /tmp etc).
>
> Why do you need nfsroot rw? In this case one client can change the nfsroot of 
> all other clients, which is maybe not desirable. Or would you provide for 
> each client an own nfsroot?

I don't want to mount the nfsroot rw, but the clients will probably need 
some writable area (if nothing else dhcp and a few other daemons will want 
to update various files) though maybe just mounting some tmpfs will be 
enough rather than anything more complex...

  -- Jon