Neutron/LBaaS/HavanaPlan

1. Integration with service type framework

- amend LBaaS extension and DB model to work with service type parameter (VIP, pool)
- integrate service types with LBaaS plugin to use service types in (2)
- client support for service types

2. Driver Framework for LBaaS plugin.

Rationale: Basic LBaaS plugin provides reasonable amount of features. However interaction with backend servers may be different for different vendors. It's not only about appliance access, but primarily about how request reaches device driver. There are several possible options here:

1) current implementation. Plugin sends notifications to agent, agent pulls configuration from the plugin.

2) "advanced reference implementation". We may want to improve reference implementation to adopt agent-scheduler approach.

3) Request proxy. After request has passed persistance layer (db plugin) it is passed to external component, which is responsible for choosing device, applying configuration, etc.

4) passive agent. Plugin performs device selection, then sends CRUD request augmented with device info to agent, where it translates the call to the driver and passes device information.

So we may create several drivers at plugin side, which will adopt these approaches. For instance, for reference implementation such driver will consist of notification sending or no-op for requests that don't send notifications. Drivers are selected using default service_type or type which is provided in request.

3. Improve object monitoring
Improve DB plugin and agents by adding PENDING_DELETE and ensuring that any object passes all necessary states during its lifetime.

4. Device Inventory component.

Rationale: Some vendor implementation may require storing available appliances and their parameters to choose to which instance logical configuration will be deployed. Such component could be made generic to support different kinds of service devices: loadbalancer, VPN, firewall, etc.

5. Routed insertion implementation
This is a complex generic feature that could be utilized by any service instance (appliance) that can act as a router.

These are core features that are needed to make LBaaS production ready. Other additional features (aside from vendor drivers) may include:

1. Agent scheduling support reference implementation.

2. HAProxy on VM

3. Capability-aware client or UI