PowerDNS part 2: getting libvirt to use it

March 30, 2025

As I detailed recently, I have authoritative DNS running inside a virtual network.

But that doesn’t mean other virtual machines will suddenly start using it for .an3! Thankfully in libvirt, dnsmasq is used for for DHCP and DNS by default. dnsmasq can forward queries for certain domains to specific servers - such as *.an3 to my PowerDNS server. This way, VMs can automatically use .an3!

dnsmasq’s configuration is very easy, so I looked at /var/lib/libvirt/dnsmasq/irl-lab.conf:

##WARNING:  THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
##OVERWRITTEN AND LOST.  Changes to this configuration should be made using:
##    virsh net-edit irl-lab
## or other application using the libvirt API.
##
## dnsmasq conf file created by libvirt

Okay. Looks like I’ll have to set it in libvirt, or my configuration will be removed.

I found that this is all I need to add to the network configuration (as it said, through virsh net-edit or an app like virt-manager):

<dns>
    <forwarder domain="an3" addr="192.168.122.2"/>
</dns>

After restarting the network (can be done with virsh net-destroy irl-lab && virsh net-start irl-lab) and starting a test VM, it seems to work:

localhost:~# ping ns1
PING ns1 (192.168.122.2): 56 data bytes
64 bytes from 192.168.122.2: seq=0 ttl=64 time=0.637 ms

What’s next?

Still a secondary. I haven’t deviated completely from my plan, this is just necessary setup!