This patch adds multi-manager support to the
NSX v3 plugin thereby enabling the ability to specify multiple
NSX managers for the v3 plugin.
This implementation supports the same basic features
as the MH multi-manager support does including;
timeouts, retries, keep-alive, etc..
The approach in a nutshell is to introduce a "proxy"
class which looks like a requests or requests.Session
object and can be used in place of requests in the
NSX REST API client. Under the covers this class handles
management of endpoint selection and connectivity.
Also note that with this patch your devstack local rc / conf
no longer needs to specify NSX_CONTROLLERS when using
the v3 plugin. Instead a comma list of managers is supported
on the NSX_MANAGERS devstack var.
Closes-Bug: #1524046
Change-Id: I433a4b9ea73de0680d64d86e2f826c092adfba87
16b105f7f5