[nova] Spawning instance that will do PXE booting

Thomas Goirand zigo at debian.org
Fri Dec 3 22:20:41 UTC 2021

On 12/3/21 10:41 PM, Julia Kreger wrote:
> Extreme magic - OpenStack Edition. At least that feels like the answer.
> In essence, we create VMs. We attach them to the network, then
> configure virtualbmc or sushy-tools to play the role of a BMC and one
> of the things that library understand is the giant switch of "boot to
> network". From there we ipxe boot. The VMs play the role of baremetal
> machines through the emulation of the BMC and they are just hooked up
> to the network.
> This does require the job to use root privileges to setup
> networking/vms. And the virtualbmc or sushy-tools service needs enough
> rights to toggle the VM's config. Would be happy to try and discuss
> specifics of the devstack plugin, but I'm unsure if that would really
> help. Regardless, you know where to find us. :)
> As an aside, when I first read the post I was thinking of booting from
> ISO images. I've known people to embed ipxe into disk images, and you
> can embed static config/instructions for booting into an ipxe binary.
> It does require custom binary builds, but it might make what you're
> trying to achieve easier.

Hi Julia!

Thanks for your answer.

Well, I've read multiple times your reply, but I have to admit I still
don't get all the details. For example, how would you "embed ipxe into
disk images" for example? Should I for example run the iPXE binary from
something like syslinux (or grub?)? But isn't iPXE usually running
*after* the BIOS of a PC gets an IP from DHCP?

I've just read a post where someone boots the iPXE binary from Grub, so
that part shouldn't be hard: format a disk, make a ext4 partition, put
the iPXE binary there, and tell grub to execute it. Is that all?!?


Thomas Goirand (zigo)

P.S: I do have some knowledge on how to prepare disk images. After all,
I've maintained the Debian OpenStack images for 3 Debian releases. So I
probably just need a few pointers...

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