Base DAL implementation and DevStack integration. Our database
schema is under design so the models may be changed later.
Partially implements: blueprint implement-dal
Initial implementation include option to use ML2 but it seem that it
will be better to use a core plugin (more control) over the process.
This just includes the Neutron side plugin. It replaces the ML2 plugin
with one that doesn't do any actual network changes, instead only
forwards it to the Cascade Service.
Before, the cascading don't know the aggregates and resource info of
the cascadeds managed by proxys, so we cannot using the most filters
to choose the proper host with nova scheduler.
By updating the aggregates(includes hosts and metadata) and resource
used info in cascaded to the cascading periodically, this problem can
when cinderClient being generated, b/c this will be helpful to break
out from recursion when cinderclient being constructed from invalid
Add re-check logic when create network faild with the Conflict Exception
whose status_code is 409, it's means another task of creating the same
network is happend and done. So there is no need to create it again, instead
we query if the network exists(by name). If we can not find the network,
then the exception raised.