epp

The EndPoint Picker (EPP)

This package provides the reference implementation for the Endpoint Picker (EPP). As demonstrated in the diagram below, it implements the extension protocol, enabling a proxy or gateway to request endpoint hints from an extension, and interacts with the model servers through the defined model server protocol.

Core Functions

An EPP instance handles a single InferencePool (and so for each InferencePool, one must create a dedicated EPP deployment), it performs the following core functions:

• Endpoint Selection
  • The EPP determines the appropriate Pod endpoint for the load balancer (LB) to route requests.
  • It selects from the pool of ready Pods designated by the assigned InferencePool's Selector field.
  • Endpoint selection is contingent on the request's ModelName matching an InferenceObjective that references the InferencePool.
  • Requests with unmatched ModelName values trigger an error response to the proxy.
• Traffic Splitting and ModelName Rewriting
  • The EPP facilitates controlled rollouts of new adapter versions by implementing traffic splitting between adapters within the same InferencePool, as defined by the InferenceObjective.
  • EPP rewrites the model name in the request to the target model name as defined on the InferenceObjective object.
• Observability
  • The EPP generates metrics to enhance observability.
  • It reports InferenceObjective-level metrics, further broken down by target model.
  • Detailed information regarding metrics can be found on the website.