[arch-releng] dhcp in archiso_pxe_* (WAS: [RFC] [archiso] Use a pure systemd enviroment)

[Gerardo Exequiel Pozzi]

On 08/22/2012 04:04 PM, Thomas Bächler wrote:
> Am 22.08.2012 11:55, schrieb Thomas Bächler:
>> Am 19.08.2012 21:15, schrieb Gerardo Exequiel Pozzi:
>>> 1) DHCP is requested again on real-root. I guess, is most cases, there
>>> is no issues since is re-assigned the same IP address. (this bug
>>> introduced recently since rc.conf enabled "network")
>> This is actually necessary. If you don't start a real DHCP daemon on
>> boot, then you won't renew your lease and the DHCP server may give the
>> IP to someone else.
>>
>> Your lease should still be valid when you re-launch DHCP, so you can
>> rely on getting the same IP. You could probably even configure dhcpcd to
>> specifically request the correct IP.
> Okay, there is more, and I think we need to change things up a little:
>
> Originally, Florian found that by using IPAPPEND 1 (or 3), you don't get
> a DNS server in the initramfs. I just had a short talk with hpa in
> #syslinux. He gave a few recommendations which lead me to the following
> findings:
>
> 1) Using ipconfig is bad because you don't run a real dhcp client that
> renews your lease as it should. 'ipconfig' is a compatibility layer that
> supports the same syntax as the old kernel-level auto-configuration,
> which is something that made sense in the last century. Nowadays, you
> can use initramfs and a real dhcp client.

I guess the same applies for nfsmount command.

>
> 2) Instead, we should
>    * run a real dhcp client in initramfs
>    * kill it at the end (make it not give away the lease), copy over the
> lease to the real system (or even leave dhcpcd running)
>
> This would force us to ask for DHCP more often, but would guarantee that
> we have a consistent IP in initramfs and after. It doesn't matter if the
> IP during PXE and during initramfs differ (which is still unlikely to
> happen).
>
>
If leave it running should notify to systemd that there dhcpcd service 
is already running.

PS: Anyway for now, I leave copytoram=y for NBD/NFS (remember that 
copytoram only copies needed *.sfs, in other works booting in x86_64 
does not copies "i686.sfs")

-- 
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1