Syslinux - Feb 2014 - [RFC, PATCH] core/pxe: Add architecture-specific discovery request for PXE config file

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s1-netboot-pxe-config-efi.html




On Monday, February 24, 2014 8:50 PM, Gene Cumm <gene.cumm at gmail.com>
wrote:
 
On Mon, Feb 24, 2014 at 10:09 PM, Jeremy Kerr <jk at ozlabs.org>
wrote:
> Hi Gene,
>
>>> What I'm looking to do here is establish a bit of a convention
for
>>> allowing machines of multiple architectures to be perform PXE
>>> configuration in a uniform way (in this case, without requiring the
DHCP
>>> server to send out different lease parameters in response to the
>>> client's DHCP architecture ID).
>>
>> How do you have multiple architectures booting from the same directory
>> at this time?? What exact string is used by network boot clients of
>> each of the three architectures?
>
> This is only in-development at this stage, so I only have this going in
> a virtual environment. I have machines of separate architectures (x86
> PC-BIOS and PowerPC OPAL) booting from the same directory of pxe
> configuration files:
>
>? /pxelinux.cfg/arch-0000
>? /pxelinux.cfg/arch-000e
>
> The arch-0000 file is being used by for the x86 machines running
> pxelinux, and arch-000e for the powerpc machines running petitboot.
No, what string is used for a file name in the TFTP request for the
boot binaries (ie pxelinux.0 bootia32.efi bootx64.efi)?? How do you
manipulate the DHCP offer to evoke this behavior (ie a BIOS machine
receiving "pxelinux.0" in the DHCP/BOOTP field "file")

http://tools.ietf.org/html/rfc2131 Figure 1 for field file.


-- 
-Gene
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On Mon, Feb 24, 2014 at 11:56 PM, Don Cupp <doncuppjr at yahoo.com>
wrote:
>
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s1-netboot-pxe-config-efi.html
Don, thanks for the reference.  If Jeremy is doing this, then the
dhcpd DOES INFACT know EXACTLY what it's booting and can easily use
different directories.

Without something like the macroing that HPA pointed out (not
implemented), you're stuck needing the COM32 modules in different
directories which requires that a config specifies a different path.
I'd still say that completely different paths for the base binary,
ldlinux and config is the best differentiation strategy followed by a
content reuse strategy.  Between symlinks on the tftpd host and
Syslinux's INCLUDE/CONFIG directives, you can get a pretty manageable
system.

-- 
-Gene
> On Monday, February 24, 2014 8:50 PM, Gene Cumm <gene.cumm at
gmail.com> wrote:
>
> On Mon, Feb 24, 2014 at 10:09 PM, Jeremy Kerr <jk at ozlabs.org>
wrote:
>> Hi Gene,
>>
>>>> What I'm looking to do here is establish a bit of a
convention for
>>>> allowing machines of multiple architectures to be perform PXE
>>>> configuration in a uniform way (in this case, without requiring
the DHCP
>>>> server to send out different lease parameters in response to
the
>>>> client's DHCP architecture ID).
>>>
>>> How do you have multiple architectures booting from the same
directory
>>> at this time?  What exact string is used by network boot clients of
>>> each of the three architectures?
>>
>> This is only in-development at this stage, so I only have this going in
>> a virtual environment. I have machines of separate architectures (x86
>> PC-BIOS and PowerPC OPAL) booting from the same directory of pxe
>> configuration files:
>>
>>  /pxelinux.cfg/arch-0000
>>  /pxelinux.cfg/arch-000e
>>
>> The arch-0000 file is being used by for the x86 machines running
>> pxelinux, and arch-000e for the powerpc machines running petitboot.
>
> No, what string is used for a file name in the TFTP request for the
> boot binaries (ie pxelinux.0 bootia32.efi bootx64.efi)?  How do you
> manipulate the DHCP offer to evoke this behavior (ie a BIOS machine
> receiving "pxelinux.0" in the DHCP/BOOTP field "file")
>
> http://tools.ietf.org/html/rfc2131 Figure 1 for field file.

Hi all,
>>
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s1-netboot-pxe-config-efi.html
> 
> Don, thanks for the reference.  If Jeremy is doing this, then the
> dhcpd DOES INFACT know EXACTLY what it's booting and can easily use
> different directories.
This approach is what I'd prefer to do (modifying DHCP lease parameters
in response to the DHCP client architecture field) because it's much
cleaner. However, is this the only accepted approach? Do we want to
support folks who don't want to modify the DHCP server config?

The reason I ask is that some provisioning tools, eg MaaS, don't assume
control of the DHCP server.

Cheers,


Jeremy