Boot from LAN


10 posts
by decimo_andrew » Thu Nov 01, 2012 7:05 pm
Hello everyone, I apologize if my English is not perfect. I would like to ask if you can do the "boot from LAN".
I would like to put the image of "rasbian" on a server and use the raspberry to boot.
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by Joe Schmoe » Thu Nov 01, 2012 8:04 pm
As always, the caveat is that you have to boot from the SD card - that's the only way the Pi can be booted. But the "rootfs" can be someplace other than the SD card - say, on USB or on NFS.

Look for a thread with the title: NFS root - totes worth it

That seems to have the latest skinny on the subject.
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by smartpatrol » Thu Nov 01, 2012 9:54 pm
Have a look at etherboot
http://etherboot.org/wiki/start
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by Wendo » Sat Nov 03, 2012 6:55 am
Etherboot won't work, don't even get your hopes up.

Currentely, and for the forseeable future, you CAN NOT boot from anything other than the SD card. I'm not going to say it's impossible, but it's pretty damn close.

The reason is that, the GPU is what actually boots the system. When it does that the only device it can access is the SD card. It can't see the network as that would require a) it knew how to even talk to ta network chip, b) that the network chip supported something like PXE or another network booting technology, and the biggest one c) that the CPU knew how to communicate over the USB bus which, at this point isn't even initialized and which the network card is at the other end of.

Now, all that said, that's not to say you won't be able to boot the just kernel from the SD card and run the rest of the system from an NFS share, but that's not network booting.
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by Joe Schmoe » Sat Nov 03, 2012 7:48 am
Right. Like I said in the first response.

However, if you want to talk semantics, you could argue that no computer (but for the sake of argument, let's focus on typical x86 hardware) actually boots from the network (or hard disk or floppy or ...). x86 machines all boot from the BIOS. What happens after that is, well, you know...

I.e., and what I'm saying, in a roundabout way, is that when you "boot from the network" on an x86 box, you're only able to do that because the BIOS has PXE support. And since the software on the SD card (on ther Pi) is the counterpart of the BIOS (on x86), it then follows that it is equally correct to say that you can "boot from the network" (on either platform).
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by normalocity » Sat Aug 24, 2013 3:17 pm
Right, but in the scenario of the RPi (unless I'm mistaken) there's no chip that serves the purpose of the BIOS from your x86 example except the SD card. In a typical x86 motherboard there's a chip that stores the BIOS. In the case of the RPi the "firmware" and such is the closest thing to the BIOS chip, and helps get the machine started.

So, to imply that it might be possible to network boot - well what is going to serve as some kind of initial startup phase on the RPi if not the SD card since there is now BIOS/CMOS chip (I don't think) that does this?
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by DeeJay » Sat Aug 24, 2013 6:23 pm
normalocity wrote:So, to imply that it might be possible to network boot -


Who is doing the implying? Two people have said, correctly to the best of my knowledge, that the RPi hardware is only capable of booting from the sd card.

OF COURSE it is possible that the code that is booted from the sd card could be some sort of minimal pre-loader that is capable of finding and transferring control to some other code, possibly an entire Operating System, located on some other storage device or even over a network connection.

BUT anyone capable of implementing that will not be deterred by the headline and simply understood statement: the RPi hardware is only capable of booting from the sd card.

Can't we agree to leave it at that and not muddy the waters?
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by blamarpa » Tue Aug 27, 2013 10:22 pm
Look at this:
http://elinux.org/RPi_iSCSI_Initiator
you need to recompile the kernel in order to support mounting an iscsi drive al bootup and the rpi needs sd card to load this kernel.
Now you can do it with a computer or NAS capable to be a iscsi target.


And this:
http://cellux.github.io/articles/moving-to-nfs-root/
The url say wath it does, move root partition to a shared NFS and do the changes to mount it al boot time too, It is also needed a sd card as in the previous solution because raspberry pi loads his firmware, SOC low level hardware config and kernel from it.

hope this helps. Regards
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by SirLagz » Wed Aug 28, 2013 4:03 am
It's potentially possible to "boot from LAN" over USB...
viewtopic.php?f=66&t=12015

Check out that thread, though I haven't been able to find out anything about how to do it
Also, it will only work with the Model A, which means you won't be able to use a USB hub while booting...or potentially running the OS.
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by Joe Schmoe » Wed Aug 28, 2013 11:53 am
SirLagz wrote:It's potentially possible to "boot from LAN" over USB...
viewtopic.php?f=66&t=12015

Check out that thread, though I haven't been able to find out anything about how to do it
Also, it will only work with the Model A, which means you won't be able to use a USB hub while booting...or potentially running the OS.


All of which makes it about 98% useless.

Cute, though...
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