Hostname IP resolution for KVM guests
Guest IP via DNS lookup
The libvirt manages the DHCP of each KVM guest. Wouldn't it be nice if the DHCP IP address mappings were correlated with the host DNS lookup so IP addresses of the guests were available via VM host name?[1]
This is how to setup you KVM host so VM guest IP addresses are available by DNS host lookup:
- install libnss-libvirt
apt install libnss-libvirt
- configure /etc/nsswitch.conf to search libvirt and libvirt_guest for DNS records.
hosts: files libvirt libvirt_guest mdns4_minimal dns myhostname mymachines [NOTFOUND=return]
🚩 Note:Make sure you name your VM guests hostname the same as their virsh domain-name.
- Obtain the list of active KVM domain (hosts if you follow the above note):
virst list
Now you can confirm what guest VM hosts are running and use those hostnames to confirm that the DNS lookup is complete:
- ping each host in the list
fping debian10-work debian11 debian96-cloud debian11-transfer debian11-transfer is alive debian10-work is alive debian11 is alive debian96-cloud is alive
it has been so painful up to this date (2023-05-30) maintaining guest host names in /etc/hostname; I am glad that is all over now.