Re: [libvirt] libvirt plans: dns support for IPv6?

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 :-)