[syslinux] Client-identifier option in PXE search order

[H. Peter Anvin]

Constantine Gavrilov wrote:
>> /> This allows us to bind the UUID to IP, and then pxelinux branches based
> />/> on the IP...
> />/> 
> />
>> You can also tell dhcpd to generate an option 209 from the UUID, if you 
>> prefer.
> 
> It is doable from dhcpd.conf, however when adding a node, one must do:
>  * add uuid entry to dhcpd.conf
>  * restart dhcp
> 

ISC dhcpd supports doing this dynamically.  The above is not true.

> It is not always desirable (or convinient) when managing multiple nodes. Also, it requires
> dhcp server that supports this.


> Ideally, for automatic node discovery and following management of discovered node, one would
> like to do:
> 
> * have simple dhcpd.conf with default boot image of pxelinux.0
> * new node boots with pxe, pxelinux.0 is booted and uses default config file
> * default ramdisk, NFS (or ISCSI) root image is booted by pxelinux.0
> * defalt image reports this new node to "management" (HW params, MAC addrs, UUID)
> * "management" sees new node. It is now available for further assignment
> * "management" assigns node to some other image. To do so, the pxe file for this node is created
> (or changed if node is reassigned).
> 
> PXE file naming scheme based on MACs achieves it, except it makes NIC replacement and
> working with multiple NICs of the same node tricky. Here, I would wish to use a PXE file
> naming scheme based on UUID. This would reduce requirements on DHCP server and would not
> require DHCP configuration changes.

You're also going to have problems with machines which don't have a 
valid UUID, which in my experience is the majority of all machines.

	-hpa