[libvirt] libvirt plans: dns support for IPv6?

[Gene Czarcinski]

On 09/13/2012 04:05 PM, Laine Stump wrote:
> On 09/13/2012 02:00 PM, Gene Czarcinski wrote:
>> I would like to know what the plans are for supporting dns for virtual
>> guests with only IPv6.
>>
>> My objective is to be able to reference a virtual guest for the host
>> ... doing ssh, scp, etc.  such functions work just fine if you specify
>> the ip-address but, after a while, those ip-addresses are difficult to
>> remember ... afterall, that is why dns exists.
>>
>> For IPv4, with a some patches to libvert implementing "--local=/virt/
>> --domain-needed" if "--domain virt" is specified, I am now able to ssh
>> to guests by name.
>>
>> The additions needed are to run the NetworkManager supporting
>> "--conf-dir=/etc/NetworkManager/dnsmasq.d/" (or patch it like I did),
>> and add a file specifying the dnsmasq on the virtual NIC.  For
>> example, server=/virt/,192.168.122.1 will forward queries.
>>
>> Alternatively, you can run yet another dnsmasq on the host which just
>> passes queries to the dnsmasq and modify your upstream dns server to
>> forward any queries for the virtual domains to the dnsmasq on the host.
>>
>> IPv6 is another situation entirely.  And it may be even more important
>> to have dns support because if IPv4 address are difficult to remember,
>> IPv6 are practically impossible.
>>
>> So, are there any plans for providing dns on the IPv6 virtual networks?
>>
>> I can see a couple of solutions and each has pluses and minuses.
>>
>> 1. Do it the same way the it is done for IPv4.  The current version of
>> dnsmasq (2.63) supports dhcp for IPv6 and, IIRC, has since 2.61. I
>> realize that you need to continue support of libvirt on RHEL 6 and
>> possibly others that are running an old version of dnsmasq, but isn't
>> it time to move along?  While you can manually configure IPv6
>> interfaces so that you can add the definitions to a /etc/host file,
>> this is not a good approach from my perspective.  The use of dnsmasq
>> also allows specification of different domains for each virtual IPv6
>> network.
>>
>> 2. There is another approach and it would be useful for both dnsmasq
>> and this approach be available.  That is, continue to use radvd and
>> have the virtual guests autoconf the ip addresses.  Then use mDNS
>> (avahi and nss-mdns) to support access by name.  This does not require
>> doing anything about dnsmasq.  In fact, it is possible thatyou do not
>> need it at all.  In addition, the plans for Fedora 18 are to make mDNS
>> the default for Desktop installs [I am not sure what that means].  A
>> big problem is that there is only a single domain which is ".local" by
>> default.  An even bigger problem is that ssh (openssh) has an error if
>> a mDNS name is specified.
>>
>> I noticed that Daniel Berrange has put in a bugzilla request that
>> dnsmasq be updated.
>>
>> If someone is already coding up patches to add dhcp for IPv6 or will
>> "real soon now", I will be happy to test it.  Otherwise, I could take
>> a shot at coming up with the patches.
> AFAIK nobody else is working on that right now, so I'd say go for it :-)
>
>
This is going to be more involved than I thought.  While dnsmasq is 
suppose to support IPv6, I can get the IP-addresses but not the dns 
update.  Right now, I believe the reason for that is that NetworkManager 
does not send the fqdn.

Gene