Data model improvement: split to customer request, response, and data persistence

[xieus]

Requests

The current Alcor is using a simplified data model where customer request input, request response, persisted data, and message exchanged among microservices remain very similar. This simplified data model serves its purpose to some extend. It is time for us to revisit and improve data model.

• D1: Customer request input is from end-customers which only contains information available from customer or admin users
• D2: Request response to customer request
• D3: Data persisted to database usually contains a superset of D1 (plus resource allocated by control plane but invisible to customers).
• D4: Message exchanged among microservices is provided by resource owners (e.g., Port Manager) and contains information required by other microservices (e.g., Subnet Manager). It is a subnet of D3.

[xieus]

@cj-chung I think it is time to look into this feature request. I will sync up with you offline.