Re: [PATCH v3 5/5] docs: Update info with grub.cfg netboot selection order

[Daniel Kiper]

On Tue, Oct 22, 2019 at 10:48:14AM +0200, Javier Martinez Canillas wrote:
> From: Robert Marshall <address@hidden>
>
> Add documentation to the grub info page that specifies the order
> netboot clients use to select a grub configuration file.
>
> Signed-off-by: Robert Marshall <address@hidden>
> Signed-off-by: Javier Martinez Canillas <address@hidden>

Wow! We have a doc! Nice!

>
> ---
>
> Changes in v3:
> - Add a patch documenting the grub.cfg netboot selection order.
>
> Changes in v2: None
>
>  docs/grub.texi | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
>
> diff --git a/docs/grub.texi b/docs/grub.texi
> index 5ac61c09d1b..e7c5b1968b3 100644
> --- a/docs/grub.texi
> +++ b/docs/grub.texi
> @@ -2486,6 +2486,48 @@ grub-mknetdir --net-directory=/srv/tftp 
> --subdir=/boot/grub -d /usr/lib/grub/i38
>  Then follow instructions printed out by grub-mknetdir on configuring your 
> DHCP
>  server.
>
> +The grub.cfg file is placed in the same directory as the path output by
> +grub-mknetdir hereafter referred to as FWPATH. GRUB will search for its
> +configuration files in order using the following rules where the appended
> +value corresponds to a value on the client machine.
> +
> +@example
> +@group
> +@samp{(FWPATH)}/grub.cfg-@samp{(UUID OF NIC)}

Hmmm... May each NIC have different UUID? I thought that UUID
is assigned to the machine not to the NIC. However, there is
a chance that I am missing something...

> +@samp{(FWPATH)}/grub.cfg-@samp{(MAC ADDRESS OF NIC)}
> +@samp{(FWPATH)}/grub.cfg-@samp{(IPv4 OR IPv6 ADDRESS)}
> +@samp{(FWPATH)}/grub.cfg
> +@end group
> +@end example
> +
> +The client will only attempt to look up an IPv6 address config once, however,
> +it will try the IPv4 multiple times. The concrete example below shows what
> +would happen under the IPv4 case.
> +
> +@example
> +@group
> +UUID: 7726a678-7fc0-4853-a4f6-c85ac36a120a
> +MAC:  52:54:00:ec:33:81
> +IPV4: 10.0.0.130 (0A000082)
> +@end group
> +@end example
> +
> +@example
> +@group
> +@samp{(FWPATH)}/grub.cfg-7726a678-7fc0-4853-a4f6-c85ac36a120a
> +@samp{(FWPATH)}/grub.cfg-52-54-00-ec-33-81
> +@samp{(FWPATH)}/grub.cfg-0A000082
> +@samp{(FWPATH)}/grub.cfg-0A00008
> +@samp{(FWPATH)}/grub.cfg-0A0000
> +@samp{(FWPATH)}/grub.cfg-0A000
> +@samp{(FWPATH)}/grub.cfg-0A00
> +@samp{(FWPATH)}/grub.cfg-0A0
> +@samp{(FWPATH)}/grub.cfg-0A
> +@samp{(FWPATH)}/grub.cfg-0
> +@samp{(FWPATH)}/grub.cfg
> +@end group
> +@end example
> +

Is it possible to assign both IPv6 and IPv4 addresses at once to the NIC?
What will happen if both are assigned? And first of all: does GRUB at
this point support IPv6?

Daniel