Re: enabling use of dnsmasq

[Gene Czarcinski <gczarcinski cox net>]

On 09/07/2012 04:39 PM, Dan Williams wrote:
> > I am doing some testing of NM using dnsmasq for a caching nameserver:
> > >
> > >  From another message:
> > > > > >>3.  Will use of dnsmasq be optional and configurable?
> > > > >It already is, you can enable or disable it via "dns=dnsmasq" in
> > > > >/etc/NetworkManager/NetworkManager.conf; and since recently, you can
> > > > >tweak the configuration using files in /etc/NetworkManager/dnsmasq.d.
> > >
> > >OK, the dns=dnsmasq works but how about the configuration tweak files in
> > >/etc/NetworkManager/dnsmasq.d ?
> Out of curiosity, what sort of things do you want to tweak?  If enough
> people need to tweak them, then perhaps we should add them in a more
> standardized format so that they still work if/when we get a mythical
> unbound plugin too.
I am using qemu/kvm/libvirt to run a number of VMs for doing varuious 
testing including some security testing.  The virtual stuff seems to 
have pretty good performance and my 6 AMD core processor with 16GB 
memeory and an SSD for root runs quite nicely.

I can remember the names of the virtual machines but not necessarily the 
ip addresses.  I would like to access vis ssh and scp those virtual 
guests from the host system by name ... by IP works.  Now, the dnsmasq 
instances started by libvirt can be queried from the host and will 
respond.  You can also specify a domain name (such as "virt") for the 
systems on that virtual network.

I need to be able to specify something like server=/virt/192.168.122.1

I patched NetworkManager-0.9.4.0-9.git20120521.fc17 to add the 
"--conf-dir=/etc/NetworkManager/dnsmasq.d" and after fiddling with 
selinux I got things to work.

There is another way which still involves running an instance of dnsmasq 
on the host's real NIC and passing "virt" queries up to 192.168.122.1 
... this also involves modifying the upstream dnsmasq to route "virt" 
domain queries back to the host.  Using the caching dsnmasq is a lot 
simpler.

When all is done, it works.  I can "ssh test.virt" and I am in.

BTW, doing this involves some updates to libvirt to add some additional 
parameters to the dnsmasq command line ... lack of these updates produce 
some "interesting" loops of dns packets looping through the network.  
The update adds "--local-/<domainname>/ --domain-needed".  I am now 
looking into doing something similar for the PTR queries ... IPV4 is not 
too bad but ipv6 is a lot more complicated.

Does that scratch your itch Dan?

Gene