[Pkg-libvirt-maintainers] Bug#587484: libvirt0: routing setup (iptables) relies on working DNS

[Daniel Friesel]

Package: libvirt0
Version: 0.8.1-2
Severity: normal


Setup:
libvirt with qemu, network managed by libvirt.

Problem:
When starting libvirt VMs when no working DNS is available, virsh is unable to
connect to libvirt and simply hangs without saying anything.
Adding the IPs configured for the VMs and corresponding (fake) hostnames to
/etc/hosts and then restating libvirt fixes this issue.

It looks like this is because the iptables calls made by libvirt to set up VM
routing do not use the -n option. So, if all DNS servers for one (or more) VM
IPs are unreachable, iptables waits a long time until reaching a timeout, and
in this time libvirt is completely unusable.

I propose to use "iptables -n" every time iptables is called by libvirt. It
should not have any negative effects and would save a lot of trouble and
debugging in case of DNS fuckups.

--derf