[ipxe-devel] iPXE and booting ISOs over the network

[Christian Nilsson]

On Fri, 12 Jun 2020 at 16:49, IT1 Stuart Blake Tener, USNR <
stuart.tener at bh90210.net> wrote:

> List members,
>
> I have done a number of web searches and am interested in gaining some
> insights into what choices I have in implementing iPXE to boot ISO files
> directly (I have read several postings that were 6 to 10 years old in this
> area but no code was really given just oh I did this, I did that). I had
> asked in an IRC channel a while ago (they are so useless, people ignoring
> your question and trying to find a different question you should be asking
> because that is what they can answer), and got a bunch of discouraging
> replies. A huge discussion ensued having nothing to do with what I had
> originally asked, and I abandoned obtaining any help there.
>
> I'd like to setup a server (as a virtual machine for portability, but
> would be fine starting as a physical server to decrease complication) with
> a singular purpose of providing iPXE/PXE booting services on my home lab
> network. I'd like to be able to have a directory or that into which I can
> plop an ISO file and then have some sort of menu generated on the fly that
> notices all ISOs in that directory and offers a menu that is presented
> whence someone boots iPXE/PXE via the network. I'd also like to have a
> sub-menu of permanent ISO choices with descriptions that can be selected
> from as well. It is my understanding that iPXE/PXE can do this quite
> easily, but then I was given a ton of reasons on the IRC why it would not
> work so I gave up in frustration trying to sort "IRC wheat from IRC chaff".
>
> My thought is to create a private 192.168.100.0/24 network in this
> environment I propose, and for the server to have TFTP, DNS, and whatever
> else is requisite installed there within. I think I'd like to use Debian to
> do it, but am open to whatever distribution people think will make this
> most easiest.
>
> Thanks in advance and I hope everyone stays safe from looting thugs and
> healthy from the pandemic.
>
>
> Very Respectfully,
>
> Stuart
>
In the iPXE forum FAQ you have the "answer" to ISO - it is still a valid
answer! (the way PCBIOS INT calls work won't be changed, and EFI has
similar issues in this regards, so there is no reason to think that a 10
year old answer is invalid)
https://forum.ipxe.org/showthread.php?tid=5948&pid=19101#pid19101
See the part about: I'm using memdisk or sanboot to boot an ISO and bootup
fails

It boils down to: booting ISO might work if what is on the ISO does not
start it's own OS (that is keep using the BIOS for all access and iPXE
stays active)
But as soon as you have some other driver that takes control of the NIC
(actually before that but it's an easy way to understand when things happen)
There is no longer any way to access the disk (ISO) and it usually fails.
(There is a few exceptions where this does work, but not many)
So due to the fact that the "boot a ISO over PXE" will fail in most cases,
it is better to pursue an approach that is known to work.

Just to be clear, first start with getting the iPXE demo boot to work the
way you want, people will be happy to help you with that!
Then feel free to try out booting ISOs, you might be lucky that it works,
but please remember that those are special cases.
(it is more likely that you will see isolinux or grub work fine, but when
Linux kernel boots it will fail to find the live system, since "there won't
be" any ISO that it can be found from)

Kind regards
Christian
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