Reading IP address given via DHCP

John Nielsen lists at jnielsen.net
Fri Sep 27 10:32:00 MDT 2013


On Sep 27, 2013, at 5:40 AM, Dan Egli <ddavidegli at gmail.com> wrote:

> On Sept. 25, 2013 at 9:58 PM, Mike Lovell wrote:
> 
>> it sounds like you have already built most of this so this suggestion
> 
>> might not be of much value. have you looked at using ipxe [1] for
> 
>> this? it can  be used with pxe to do all kinds of cool things like
> booting
> 
>> from http, iscsi, fcoe, or others and has a limited scripting ability.
> 
>> ipxe could do a  workflow like this:

See also http://etherboot.org/wiki/index.php. I recently set up an iSCSI boot environment using gPXE and UNDI without too much trouble.
Also here: http://etherboot.org/wiki/pxechaining

> Just out of curiosity, what IS fcoe? For that matter, I keep hearing about
> iscsi, but the only *scsi things I've ever heard about are the old trio of
> SCSI, Ultra SCSI (USCSI) and Ultra-Wide SCSI (UWSCSI). This iscsi thing is
> an unknown to me besides the fact that I've heard of it before. :)

FCOE and iSCSI are both technologies that blur the line between SAN and NAS. The allow one host to access a disk or volume on another host as if it were directly connected. Fibre Channel is a traditional SAN technology that required a dedicated (and expensive) network. I only used it a few years ago and 4Gbps was considered shiny. Now with 1Gbps Ethernet practically free and 10Gbps Ethernet available it makes less sense to have a dedicated SAN network.

http://en.wikipedia.org/wiki/Fibre_Channel_over_Ethernet
http://en.wikipedia.org/wiki/Fibre_Channel

iSCSI is similar. It uses any IP network (the 'i' in the name) to connect a client (initiator) with a volume on the server (target). On Linux such a volume shows up as /dev/sdN, just like a local disk. It used to be somewhat of a niche thing, but now there's good support for it in most major operating systems. Many servers and even some consumer-grade machines support booting from iSCSI in the onboard BIOS. But even without that it's not _too_ hard to set up with PXE. My recent project involved a PC with Windows installed locally (for the benefit of other family members). For the project, I set up one iSCSI volume with a Fedora installation and another with FreeBSD. The BIOS was set to PXE boot but the PXE menu included an option to boot the local Windows installation.

http://en.wikipedia.org/wiki/Iscsi

JN



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