I haven't had the time to fix it yet, but wanted to point out that the
patches that are supposed to support setting the peer address of
tap/macvlan devices do not work. The problem is that the peer attribute
isn't being included when the XML for a a domain interface is being
formatted.
I also sent the following message last week as a followup to the patch
series; possibly it wasn't noticed for that reason:.
I'll make a patch to fix the formatting when I can so that I can test my
theory about address vs. peer on lxc vs qemu. But if it's fixed by
someone else in the meantime, all the better :-)
On 04/20/2016 12:36 PM, Laine Stump wrote:
Something I've found myself worrying about lately while driving in the
car or nodding off to sleep - are the "address" and "peer" attributes
effectively used in the same way for all network connection types and
both hypervisors? I think the answer may be "no", and if so we need to
fix that before they go out in a release.
In particular, when an lxc domain's interface has:
<ip address='192.168.128.1'/>
That is the IP address seen by the guest, not the host. So I would
assume that if an LXC domain had:
<ip address='192.168.128.1' peer='192.168.128.2'/>
that 192.168.128.1 would still be the IP address see by the guest, and
192.168.128.2 would be the IP address on the host side; and it should
be the same for qemu.
From what I can see of the code, though, on a qemu domain, the IP
address is set for the tap device's own IP, meaning that it would show
up on the *host* side, while the peer address would be what the host
expects to be at the other end of the tap device (i.e. the guest
side), so the two attributes are used for the *opposite* end of the
PTP link in lxc vs. qemu.
I think that, instead, the "address" attribute should *always* be the
IP address that is seen/used by the guest, and the "peer" attribute
should be the IP address that is seen/used by the host. (perhaps
"peer" could be replaced with some other name, like "host" or
"hostAddress" to avoid confusion? (don't like either of those
alternatives, but I don't really like peer either)).
Aside from that, I can see that these patches have been pushed in the
code that I'm running, and I've been trying to add "peer='blah'" to
interface IP addresses on my test machine, but it's just removed from
the config. Have you tested what got pushed? Has something gone wrong?
Since there hasn't been a release with these patches included yet,
there is still time to fix it at least to be consistent (assuming that
my suspicions are correct; I've been unable to test it myself for the
reason above).
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