network: send node hostname to DHCP server

[dimatha]

Feature Request

Ability to send node hostname to the DHCP server (option 12?)

Description

We are relying on our DHCP server to update DNS records for our DHCP clients and need the ability to provide Talos hostname to the DHCP server

[smira]

Thanks, that makes perfect sense to me. Talos might not have hostname on the initial DHCP request, but it should be able to send it while renewing the lease.

[dimatha]

Yeah, I got the point - the configuration might be applied after the network is up? That means that the system will not be registered with DNS until the least reaches 50%. I'll do some captures as I still don't see the hostnames registered with the DHCP server.

[smira]

There are many ways to set the hostname (including getting it from the DHCP server), so Talos might learn the hostname after the initial DHCP or before that, but still when it knows the hostname, it could update the DHCP server.

[dimatha]

That's actually related to siderolabs/cluster-api-bootstrap-provider-talos#96
We use CAPI/CAPV + CABPT/CACPPT.
The idea is to use the Machine name provided by CAPI and DHCP client to ship the right hostname to the DHCP server for DNS update (we do not control the DHCP server and it will be harder to preconfigure the reservations there, keeping in mind the whole automation that CAPI already does)
Currently the hostname defaults to 'talos-1.2.3.4'