Comment 2 for bug 1540512

@Carl - Hi, thanks for your comments.

First, I should make clear that I'm mentoring Petra for this work, as part of the Outreachy program. Hence the overlap with the clustered IP allocation ideas that we've discussed a few times before. (As opposed to being a surprisingly detailed coincidence :-))

Secondly, I must admit that I'm behind on reviewing the latest revision of your spec, and it's indeed possible that it could now be pressed into service to deliver the clustered IP allocation that Calico wants. I plan to re-review the spec and form a detailed view on this in the next few days.

Even if that was the case, though, do you not think that it would also be interesting to explore using pluggable IPAM here? Pluggable IPAM is still a young technology, and in the short term I think an interesting area for a new developer to poke and contribute to; and in the long term I don't think it would be bad if we had two viable ways to achieve clustered IP allocation.

Your second paragraph above (apart from the last sentence) is exactly right. With Calico the boundaries are soft, because (1) we still want to allow arbitrary VM migration, and (2) we just need to cluster enough so that we can aggregate VM routes sufficiently, so that the complete required routing table will fit in an L3 fabric router.