Yes, except that it does not work. As you can see below, libnss-libvirt is installed and configured, but the VM "KVM-Ubuntu-GNS3-Server-17.04" is not reachable through its DNS name.

# apt-cache policy libnss-libvirt

libnss-libvirt:

Installed: 3.0.0-4

...

# cat /etc/nsswitch.conf

passwd: compat

group: compat

shadow: compat

hosts: files libvirt libvirt_guest mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns

networks: files

protocols: db files

services: db files

ethers: db files

rpc: db files

netgroup: nis

# systemctl status libvirtd

● libvirtd.service - Virtualization daemon

Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)

Active: active (running) since Fri 2017-06-16 11:44:59 CEST; 11min ago

Docs: man:libvirtd(8)

http://libvirt.org

Main PID: 9448 (libvirtd)

CPU: 1.790s

CGroup: /system.slice/libvirtd.service

├─ 5556 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

├─ 5557 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

...

├─ 8805 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

├─ 8806 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper

├─ 9448 /usr/sbin/libvirtd

└─15116 qemu-system-x86_64 -enable-kvm -name guest=KVM-Ubuntu-GNS3-Server-17.04,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/

...

Jun 16 11:55:14 samsung-ubuntu dnsmasq-dhcp[8805]: DHCPREQUEST(virbr0) 192.168.122.124 52:54:00:03:9f:9f

Jun 16 11:55:14 samsung-ubuntu dnsmasq-dhcp[8805]: DHCPACK(virbr0) 192.168.122.124 52:54:00:03:9f:9f KVM-Ubuntu-GNS3-Server-17

# ping KVM-Ubuntu-GNS3-Server-17.04

ping: KVM-Ubuntu-GNS3-Server-17.04: Name or service not known

# ping KVM-Ubuntu-GNS3-Server-17.04.actionmystique.net

ping: KVM-Ubuntu-GNS3-Server-17.04.actionmystique.net: Name or service not known

# ping 192.168.122.124

PING 192.168.122.124 (192.168.122.124) 56(84) bytes of data.

64 bytes from 192.168.122.124: icmp_seq=1 ttl=64 time=0.181 ms

64 bytes from 192.168.122.124: icmp_seq=2 ttl=64 time=0.165 ms

A few possible explanations for that issue are:

- something is not configured correctly

- there is an incompatibility with NetworkManager

- there is a bug with libnss-libvirt

- I'm missing something

On Fri, Jun 16, 2017 at 10:49 AM, Michal Privoznik <mprivozn@redhat.com> wrote:

On 06/10/2017 08:53 PM, jean-christophe manciot wrote:
> Hello everyone,
>
> I have multiple virtual networks defined on my Server:
> # virsh net-list --all
> Name State Autostart Persistent
> ----------------------------------------------------------
> default active yes yes
> ...
> virtual-mgt-5 active yes yes
> ...
>
> When a VM is started on one of them with an interface which needs the
> dnsmasq DHCP server to get its IP address/len, it remains inaccessible with
> the FQDN once the IP information is acquired.
>
> The default values are used for each dnsmasq instance:
> ● libvirtd.service - Virtualization daemon
> Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor
> preset: enabled)
> Active: active (running) since Sat 2017-06-10 19:48:58 CEST; 3ms ago
> Docs: man:libvirtd(8)
> http://libvirt.org
> Main PID: 25365 (libvirtd)
> Tasks: 35 (limit: 4915)
> Memory: 27.1M
> CPU: 28ms
> CGroup: /system.slice/libvirtd.service
> ├─22262 /usr/sbin/dnsmasq
> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> ├─22263 /usr/sbin/dnsmasq
> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> ...
> ├─24061 /usr/sbin/dnsmasq
> --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro
> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> ├─24062 /usr/sbin/dnsmasq
> --conf-file=/var/lib/libvirt/dnsmasq/virtual-mgt-5.conf --leasefile-ro
> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> ...
> ├─25365 /usr/sbin/libvirtd
> └─25384 /usr/sbin/dnsmasq --help
>
> I wonder whether the option "--leasefile-ro" gets in the way or not: there
> must be a key=value in /etc/libvirt/qemu/networks/<virtual_network>.xml to
> enable this behavior, but could not find it in the Network XML format

> <https://libvirt.org/formatnetwork.html>.

The --leasefile-ro argument is added unconditionally, just like
--dhcp-script. If you want to do name translation, either have static IP
addresses and edit the hosts file, or use NSS module:

https://libvirt.org/nss.html

Michal

Jean-Christophe