feat: add support for custom search domains

[DmitriyMV]

New config field machine.network.searchDomains supports specifying custom search domains.

For the node it will look something like this:

nameserver 127.0.0.53

search my-custom-search-name.com my-custom-search-name2.com

For the pods it will look something like this:

search default.svc.cluster.local svc.cluster.local cluster.local my-custom-search-name.com my-custom-search-name2.com
nameserver 10.96.0.10
options ndots:5

Fixes #9342

[DmitriyMV]

/m

[flpajany]

Hi @DmitriyMV,

We have the same problem with our talos clusters where we have several DNS domains.

Currently we are running our clusters in talos 1.7 and we do not plan to upgrade to 1.8 or 1.9 in the near futur.

So please, is it possible to backport this feature in talos 1.7 ?

Thank you so much.
Regards,

[DmitriyMV]

@flpajany greetings! Thanks for the request. Unfortunately we do not backport changes that modify machine config or proto resources. Those backports leaves a big chance of accidentally breaking things.

[flpajany]

I understand. Is there a way to change the seach path for DNS resolution manually ?

[smira]

I understand. Is there a way to change the seach path for DNS resolution manually ?

This PR is mostly about host search path in the /etc/resolv.conf.

See #9342 for discussion for K8s pods and others.

[flpajany]

It is exactly what I am talking about : a way to change /etc/resolv.conf and add other domains to the search path to the host.

I was thinking about changing machineconfig to add something like this :

machine:
    files:
        - path: /etc/resolv.conf
          op: append
          content: 'search mydomain.com'
          permissions: 0o644

Edit : tested and not working :-(

[smira]

this won't work most probably.

you can achieve the same by setting the hostname to the fqdn as well.

[flpajany]

this won't work most probably.

you can achieve the same by setting the hostname to the fqdn as well.

I understand but unfortunatly it is complicated to do that for some applications. We'll try nonetheless to change it that way and I'll be back here to tell you the result.

[smira]

Also keep in mind that k8s pod search path is totally independent of this change.

[flpajany]

That would mean to rebuild container images, thing we are not able to do :-(

[smira]

Please read #9342 carefully. If you have any specific question - create a GitHub discussion with all relevant information.

[flpajany]

OK we'll try this too. Thx