Neutron/LBaaS/CommonAgentDriver

LBaaS Common Agent-based Driver

Rationale

Haproxy-on-host reference implementation which is using agents is quite specific:

• with haproxy it is easier to deploy the whole loadbalancer config from scratch every time then to create/update/delete separate components
• namespace driver needs virtual interface driver on init, other drivers may have their own specific parameters

So it is useful to unify reference agent implementation to:

• make it suite any driver which wants to use async mechanism
• have single lbaas agent type and hense single agent scheduling mechanism

What is required

1. Revision of agent API
2. Revision of agent loading device driver(s) mechanism
3. Add optional device_driver field to ServiceProvider. Should be passed to lbaas agent if present.