[libvirt-users] Speaking of DNSmasq ....

[Steve Gordon]

> .... I am getting a bit tired of those pesky DNSmasq entries in my
> syslog file, they fill it up about weekly, wash other stuff out of
> view
> on a tail. Is there any way to suppress them. or else increase their
> lease time so that they happen less frequently ? Having a finite
> lease
> time for a VM seems nonsensical, it can't go anywhere or disconnect
> (obviously) .... I tried restarting DNSmasq, but it said 'Socket
> busy'
> or some such & didn't restart. Someone on another list said that
> DNSmasq
> was/is in fact started by libvirt/KVM/QEMU, & I poked around in the
> various /etc/sysconfig files, but couldn't find anything related to
> DNSmasq, whatever options it is started with seem to be hardwired or
> compiled into one of the pertinent executables .... FC 14, 64 bit,
> terminally patched up, libvirt 0.8.3-10.fc14 64-bit, qemu-KVM
> 2:0.13.0-1.fc14 64-bit .... TIA ....

Hi William,

If you are running/using libvirt then chances are that it is indeed spawning an instance of dnsmasq listening on the virtual network. The dnsmasq instance is spawned based on a combination of hard-coded/default values and network configuration specified in the libvirt xml files, by default /var/lib/libvirt/network/default.xml (at least on my F16 box anyway). Unfortunately I do not think lease time is currently one of the supported configurable values (http://libvirt.org/formatnetwork.html), but you always raise a bug/rfe and ask for it to be added :).

My approach in the past with these situations in the meantime has been to kill off the libvirt spawned dnsmasq instances and use the system wide dnsmasq service instead, specifying both the configuration values libvirt *would* have used (libvirt feeds all the values as command line args so you can easily view them when the dnsmasq process is running) and the additional ones I need which are not supported by the xml currently.

-Steve