[libvirt] [PATCH] network: don't add "no-resolv" if we still need DNS servers from resolv.conf

[Jiri Denemark]

On Fri, Mar 17, 2017 at 13:13:11 -0400, Laine Stump wrote:
> On 03/17/2017 12:58 PM, Jiri Denemark wrote:
> > On Fri, Mar 17, 2017 at 12:33:14 -0400, Laine Stump wrote:
> >> It was pointed out here:
> >>
> >>   https://bugzilla.redhat.com/show_bug.cgi?id=1331796#c4
> >>
> >> that we shouldn't be adding a "no-resolv" to the dnsmasq.conf file for
> >> a network if there isn't any <forwarder> element that specifies an IP
> >> address but no qualifying domain. If there is such an element, it will
> >> handle all DNS requests that weren't otherwise handled by one of the
> >> forwarder entries with a matching domain attribute. If not, then DNS
> >> requests that don't match the domain of any <forwarder> would not be
> >> resolved if we added no-resolv.
> >>
> >> So, only add "no-resolv" when there is at least one <forwarder>
> >> element that specifies an IP address but no qualifying domain.
> > ...
> > So what if the network is isolated and supposed to only resolve names
> > according to its database. Such network does not have any <forwarder/>
> > element and yet no-resolve should be added in the configuration.
> 
> You forced me to remember that I had fixed exactly that hole a *long
> time* ago (far before <forwarder> was added). I looked it up and found
> commit 513122ae:
> 
>   https://bugzilla.redhat.com/show_bug.cgi?id=723862
> 
> which adds no-resolv if the network is isolated. I was momentarily
> afraid that the no-resolv added in that patch had been "messed with" at
> some later time, causing a regression in my fix, but found that it's
> still there (look around line 1216).
> 
> So in the case of an isolated network, we still add no-resolv, no matter
> whether we've added it due to <forwarders> or not.

And I see we even have a test case for isolated network and no-resolv is
still there.

ACK

Jirka