Chain-booting PXE bootloaders

Chain-booting PXE bootloaders

[Turner, Ian]

Hello all,

We're trying to chainload PXE bootloaders. This is required in order to netboot Windows or DOS, and is also useful for Solaris jumpstart builds. Is this feature supported by GRUB? Simply running the following command line causes GRUB to read the configuration file the TFTP server, then either hang or reboot:

chainloader --force /path/to/pxelinux.0
boot

Thanks in advance for your thoughts.

--Ian Turner

Re: Chain-booting PXE bootloaders

[Vladimir 'φ-coder/phcoder' Serbinenko]

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On 08/27/2010 01:04 AM, Turner, Ian wrote:
> Hello all,
>
> We're trying to chainload PXE bootloaders. This is required in order to netboot Windows or DOS, and is also useful for Solaris jumpstart builds.
It's not supported because of a priori no clear benefits present.
@Seth can you comment on Solaris part?
DOS is best loaded using grub+memdisk (later one is a helper available
from syslinux pages).
Could you detail the windows part?
>  Is this feature supported by GRUB? Simply running the following command line causes GRUB to read the configuration file the TFTP server, then either hang or reboot:
>
> chainloader --force /path/to/pxelinux.0
>   
Usually if someone tells you "wrong signature" it may mean something...
--force was added because of now dead SCO (now Tarantella, don't confuse
with Litigious Bastards) Unix. Removing it may create some hassle if
someone uses it so it's kept.
> boot
>
> Thanks in advance for your thoughts.
>
> --Ian Turner
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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RE: Chain-booting PXE bootloaders

[Turner, Ian]

Here are a couple of use cases:

Windows:
http://technet.microsoft.com/en-us/library/cc722358%28WS.10%29.aspx

Solaris:
http://redhatcat.blogspot.com/2008/07/loading-pxegrub-from-pxelinux.html

Other random proprietary software:
http://syslinux.zytor.com/archives/2006-April/006811.html

It seems like what this requires is to leave the UNDI & PXE drivers loaded, then load the chain image and jump to it.

If this isn't supported as-is, no worries, just wanted to check if it was expected to work. Let me know if you need more information on Windows. I am not a Windows guy myself so can only go so deep.

Cheers,

--Ian

-----Original Message-----
From: grub-devel-bounces+ian.turner=deshaw.com@gnu.org [mailto:grub-devel-bounces+ian.turner=deshaw.com@gnu.org] On Behalf Of Vladimir 'f-coder/phcoder' Serbinenko
Sent: Thursday, August 26, 2010 7:22 PM
To: grub-devel@gnu.org
Subject: Re: Chain-booting PXE bootloaders

On 08/27/2010 01:04 AM, Turner, Ian wrote:
> Hello all,
>
> We're trying to chainload PXE bootloaders. This is required in order to netboot Windows or DOS, and is also useful for Solaris jumpstart builds.
It's not supported because of a priori no clear benefits present.
@Seth can you comment on Solaris part?
DOS is best loaded using grub+memdisk (later one is a helper available
from syslinux pages).
Could you detail the windows part?
>  Is this feature supported by GRUB? Simply running the following command line causes GRUB to read the configuration file the TFTP server, then either hang or reboot:
>
> chainloader --force /path/to/pxelinux.0
>   
Usually if someone tells you "wrong signature" it may mean something...
--force was added because of now dead SCO (now Tarantella, don't confuse
with Litigious Bastards) Unix. Removing it may create some hassle if
someone uses it so it's kept.
> boot
>
> Thanks in advance for your thoughts.
>
> --Ian Turner
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

Re: Chain-booting PXE bootloaders

[Vladimir 'φ-coder/phcoder' Serbinenko]

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On 08/27/2010 01:51 AM, Turner, Ian wrote:
> Here are a couple of use cases:
>
> Windows:
> http://technet.microsoft.com/en-us/library/cc722358%28WS.10%29.aspx
>
>   
Hm, this case is the only when it's necessary.
> Solaris:
> http://redhatcat.blogspot.com/2008/07/loading-pxegrub-from-pxelinux.html
>
>   
Solaris is loaded with multiboot
> Other random proprietary software:
> http://syslinux.zytor.com/archives/2006-April/006811.html
>   
This example doesn't need chainloading. Just:
linux16 (pxe)/memdisk
initrd16 (pxe)/floppy.img

Same as with normal chainloader windows usecase is enough. And same as
with normal chainloader it'll be misused for not-sane things. But as I
figured out, we can't do anything more than recommend sane configs. If
users do things improper way it's their right to.
> It seems like what this requires is to leave the UNDI & PXE drivers loaded, then load the chain image and jump to it.
>
> If this isn't supported as-is, no worries, just wanted to check if it was expected to work. Let me know if you need more information on Windows. I am not a Windows guy myself so can only go so deep.
>
> Cheers,
>
> --Ian
>
> -----Original Message-----
> From: grub-devel-bounces+ian.turner=deshaw.com@gnu.org [mailto:grub-devel-bounces+ian.turner=deshaw.com@gnu.org] On Behalf Of Vladimir 'f-coder/phcoder' Serbinenko
> Sent: Thursday, August 26, 2010 7:22 PM
> To: grub-devel@gnu.org
> Subject: Re: Chain-booting PXE bootloaders
>
> On 08/27/2010 01:04 AM, Turner, Ian wrote:
>   
>> Hello all,
>>
>> We're trying to chainload PXE bootloaders. This is required in order to netboot Windows or DOS, and is also useful for Solaris jumpstart builds.
>>     
> It's not supported because of a priori no clear benefits present.
> @Seth can you comment on Solaris part?
> DOS is best loaded using grub+memdisk (later one is a helper available
> from syslinux pages).
> Could you detail the windows part?
>   
>>  Is this feature supported by GRUB? Simply running the following command line causes GRUB to read the configuration file the TFTP server, then either hang or reboot:
>>
>> chainloader --force /path/to/pxelinux.0
>>   
>>     
> Usually if someone tells you "wrong signature" it may mean something...
> --force was added because of now dead SCO (now Tarantella, don't confuse
> with Litigious Bastards) Unix. Removing it may create some hassle if
> someone uses it so it's kept.
>   
>> boot
>>
>> Thanks in advance for your thoughts.
>>
>> --Ian Turner
>>
>> _______________________________________________
>> Grub-devel mailing list
>> Grub-devel@gnu.org
>> http://lists.gnu.org/mailman/listinfo/grub-devel
>>
>>   
>>     
>
>   
>
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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RE: Chain-booting PXE bootloaders

[Turner, Ian]

> Solaris is loaded with multiboot
> > Other random proprietary software:
> > http://syslinux.zytor.com/archives/2006-April/006811.html

Solaris cannot be PXE loaded with standard multiboot, because they have a proprietary way to pass DHCP information into the operating system. Without that it won't configure the network to finish the boot process. The relevant snippet from the patched Solaris GRUB is here:

    322   case KERNEL_TYPE_MULTIBOOT:
    323       /* Multiboot */
    324 #ifdef SUPPORT_NETBOOT
    325 #ifdef SOLARIS_NETBOOT
    326       if (current_drive == NETWORK_DRIVE) {
    327     	/*
    328 	 *  XXX Solaris hack: use drive_info to pass network information
    329 	 *  Turn off the flag bit to the loader is technically
    330 	 *  multiboot compliant.
    331 	 */
    332     	mbi.flags &= ~MB_INFO_DRIVE_INFO;
    333   	mbi.drives_length = dhcpack_length;
    334   	mbi.drives_addr = dhcpack_buf;
    335       }
    336 #endif /* SOLARIS_NETBOOT */
    337 #endif
    338       multi_boot ((int) entry_addr, (int) &mbi);
    339       break;

In order to PXE boot Solaris 10 using grub2, it either needs the above hack or it needs PXE chainloading.

Cheers,

--Ian