Resource allocation and netplugin

[mapuri]

Right now the resource allocation is implemented inside the netplugin using a global configuration state that contains state about configurable pools of IP, vlans etc and it publishes by some operational state about resource state (like consumed/free ids etc).

This quickly get's tricky in a multi-host environment where each netplugin implementation now needs to do resource allocation on it's own and publish back operation state.

A brief discussion of issues is here as well (issue #6). This issue tracks changes for a working solution.

[jainvipin]

@mapuri - distributed lock in etcd can offer the global allocation be done locally, in a clustered environment. A very common use case of distributed lock is to work on a compare-and-swap operations that otherwise would need to be done by a controller/central entity. Etcd docs recommend using this implementation

[mapuri]

@jainvipin, I was not just referring to global lock problem but the requirement for hosts to read states of other hosts in order to come up with next available value. Actually a distributed lock in this case might slow down things depending on amount of state that needs to be kept locked whenever a host needs to allocate a resource.

I think this logic can be much simpler when done centrally at one place.

[mapuri]

closing the issue, as it is addressed by in basic form by PR #23