Dear Maintainer,

When doing a network-install of a system, if one passes `hostname=foo`
on the kernel commandline, the installer will use that to set the
hostname of the installed system...

EXCEPT if there's reverse-DNS for the IP address that we happen to have
gotten from DHCP, in which case that takes precedence. But it shouldn't,
we very explicitly are requesting a hostname to set.

This situation happens in environments with dynamic dns where a client
may have released an IP, the DHCP gave it out to this new client, but
there's still a DNS cache with the old mapping.

The installer should prefer the explicit preference set by the
adminsitrator over the implicit one. Or, at the very least provide a
configuration option to enable such a behavior.

Hello Phil,

Phil Dibowitz <phil@ipom.com> (2021-03-01):

In src:netcfg's templates[1]:

    Template: netcfg/get_hostname
    Type: string
    Default: debian
    # :sl1:
    _Description: Hostname:
     Please enter the hostname for this system.
     .
     The hostname is a single word that identifies your system to the network.
     If you don't know what your hostname should be, consult your network
     administrator. If you are setting up your own home network, you can make
     something up here.

    Template: netcfg/hostname
    Type: string
    Description: for internal use; can be preseeded
     Hostname to set for the system; ignores names provided by DHCP or DNS.

 1. https://salsa.debian.org/installer-team/netcfg/-/blob/master/debian/netcfg-common.templates

The preseed doc[2] suggests the former is behind the (bare) hostname
alias. Try setting the latter?

 2. https://www.debian.org/releases/bullseye/amd64/apbs02.en.html#preseed-aliases


Cheers,

Am 2. März 2021 09:52:06 MEZ schrieb Cyril Brulebois <kibi@debian.org>:

Yes, the installation-guide under
https://www.debian.org/releases/bullseye/amd64/apbs04.en.html
even explicitly states this, indeed:

# If you want to force a hostname, regardless of what either the DHCP # server returns or what the reverse DNS entry for the IP is, uncomment # and adjust the following line. #d-i netcfg/hostname string somehost


Holger

Hi,

Thanks for pointing that out! Don't know how I missed that.

However, that requires a per-host preseed, where as with kernel command
line I can have the same preseed for all my hosts (or at least all hosts
in a certain category) and simply just pass in a hostname in the
tftpseed (which has to be host specific anyway and for me is already
generated by my provisioning system).

So perhaps it would be useful to have a like netcfg/hostname_priority
flag where one can choose a priority order?

+1