AZAwareWeightScheduler is based on WeightScheduler and provides a way to make
DHCP agent scheduling be AZ-aware. This is used in conjunction with
dhcp-agents-per-network config option and per-network agents (such as dnsmasq)
will be distributed across neutron-dhcp-agents that have availability_zone
configuration (based on dhcp-load-type for placement calculation).
bp: https://blueprints.launchpad.net/neutron/+spec/add-availability-zone
Upgrade impact is mentioned here:
specs.openstack.org/openstack/neutron-specs/specs/mitaka/availability-zone.html
The spec mentions that by default all agents belong to 'nova' AZ so
the scheduler change should be backwards-compatible.
Change-Id: I4d948efa157573fdbc0fbfd3b1efb21b69a713ef
Closes-Bug: #1796068
1e6430f9c6