Weird bug or broken config with ubuntu lxc

[Padi100]

Hello everybody,

I hope this is the right place to post this weird issue I have with LXC container.

If I create an LXC with Debian 11 / 12 the DNS configuration from the DHCP Server is used. But with Ubuntu 22.04 / 23.04 / 23.10 the resolv.conf is always overwritten by the dns settings of the proxmox host. Is this normal behaviour for Ubuntu LXC?

Ubuntu LXC with wrong DNS setting but the correct IP:


Debian LXC with correct DNS settings:

 

[dietmar]

You can configure the DNS settings for the Container using the GUI.

 

[Padi100]

Yes, I know. That's my problem. I don't understand why the ubuntu-lxc uses the settings from the host and on debian not. The ubuntu container doesn't get the DNS-Settings and I want to know if this is intended or not. Because for me it doesn't make sense that two different linux OS handle the DNS settings received from the DHCP server differently.

 

[ambad4u]

i would 2nd the motion on this

no issues if using debian lxc & or alpine lxc
but if using ubuntu (24.04 & 24.10), DNS behaves as what @Padi100 is experiencing

supplying a DNS server on the GUi makes it work

btw, i have an OpenWRT vm supplying all ip/dhcp/dns/internet stuff to all the vm/lxc, debian & alpine gets the right values but ubuntu does not...

pveversion:

pve-manager/8.3.3/f157a38b211595d6 (running kernel: 6.8.12-7-pve)

 

[gregc]

I have the same issue. Futhermore on ubuntu 24.04 LXC contaienr the touch /etc/.pve-ignore.resolv.conf trick does not work, I cannot get ubuntu LXC to grab DNS config set by DNS server (https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_guest_operating_system_configuration)

Has anyone been able to make ubuntu 24.04 LXC get DNS server via DHCP?