Kermit,
NBD has its own protocol, so there's nothing to be gained there. But
ipxe gives us the option to fetch the vmlinuz image via HTTP rather than
TFTP. In normal situations this won't make any difference, but in our
network (with a wireless bridge between two buildings) TFTP took 7 mins
to download that 5.6M image, resulting in super slow booting clients.
Using HTTP resolved this.
In ipxe it looks like this:
kernel tftp://192.168.1.12/ltsp/amd64/vmlinuz ##TFTP
kernel http://192.168.1.12/vmlinuz ##HTTTP
But yes you're right, not the NBD images - they are just accessed as
needed via the NBD daemon, never downloaded fully.
On Wednesday, 11 March, 2015 09:41 AM, Short, Kermit wrote:
This is fantastic information! Thank you, Graham! We currently send
kernels and initrd images from a web server... I.E. Replace your tftpd
with http in your kernel lines. Were these the images you refer to,
or are you talking about the actual nbd images? I thought those had
to come from an nbd daemon?
Thank you for the help!
-Kermit
--
Kermit Short
DCS-ISS
*
*
------------------------------------------------------------------------
*From:* Graham Innes
*Sent:* Tuesday, March 10, 2015 5:41:37 PM
*To:* ltsp-discuss@lists.sourceforge.net
*Subject:* Re: [Ltsp-discuss] LTSP, NBD, and iPXE
> On Wednesday, 11 March, 2015 06:04 AM, Short, Kermit wrote:
> I am unable to utilize the typical tftp/pxe boot systems due to
various organization mandated policies. To get around this, I'm using
ipxe.
We use ipxe from a server, but using it from a local USB flash drive
would work the same way. With NBD:
:server1tftp
imgfree
echo Booting from LTSP 1 (TFTP)
kernel tftp://192.168.1.12/ltsp/amd64/vmlinuz root=/dev/nbd0
init=/sbin/init-ltsp vt.handoff=7 nbdroot=192.168.1.12:/opt/ltsp/amd64
|| goto server2
initrd tftp://192.168.1.12/ltsp/amd64/initrd.img || goto server2
boot || goto server2
(in this case, if it fails along the way, it tries from server2... ||
goto server2 )
If you want to speed up image loading, you can also use HTTP to load the
image with ipxe (this helped us enormously when booting clients
connected to the main network via a wireless bridge; for reasons beyond
me TFTP was impossibly slow, HTTP works as fast as the bridge):
:server1
imgfree
echo Booting from LTSP 1 (HTTP)
kernel http://192.168.1.12/vmlinuz root=/dev/nbd0 init=/sbin/init-ltsp
vt.handoff=7 nbdroot=192.168.1.12:/opt/ltsp/amd64 || goto server1tftp
initrd http://192.168.1.12/initrd.img || goto server1atftp
boot || goto server1tftp
Obviously this requires setting up a simple webserver to host the
images. We use lighttpd.
We also like to have some clients boot from one server, and some from
another server, based on MAC address. This is also possible with ipxe:
iseq ${netX/mac} ac:22:0b:c5:9f:b5 && goto server1 || #PC01
Graham
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