[ipam] automatic allocation of addresses for `weave expose`

[stlalpha]

If I instantiate an allocator for 172.16.100.0/24 on the weave network, I want the hosting operating system (the one that is hosting the weave router docker image) to be able to request and receive a dynamic IP from that allocator. It should be able to fully participate in the ip allocation/deallocation feature set as the containers themselves can. Ideally this is something akin to the current capability of:

weave expose 172.16.100.20/24

But instead - you would be able to do something like:

weave attach 172.16.100.0/24

from the hosting operating system.

[rade]

This is already on our roadmap, though hadn't hitherto been captured as a separate issue. So thank you.

The general approach we have been taking with IPAM is to tweak the existing command sets such that where they currently accept a CIDR, they will (also) except a) nothing, b) b a network. So we'd likely tweak weave expose rather than introduce a separate command.

[rade]

I believe this will be addressed by #563.

[dpw]

With #563, we automatically allocate an address when you do weave expose.