InferencePool config proposal for API review

[ahg-g]

Proposal at https://docs.google.com/document/d/1RKVFAgerUoIMhClU9gRduXoF8Hq2tzzVOHdPvkQPKgs/edit?tab=t.0

/hold

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[kfswain]

This is intended to be post-v0.1, correct?

[ahg-g]

1. Need to support extensions possibly running outside the cluster
2. Need to support "localhost" to run extensions as a sidecar

[ahg-g]

@danehans @robscott If we change this to a Service ref, then the absence of it could mean that the extension is deployed as a sidecar.

[robscott]

If this is a generic k8s object ref that defaults to Service, is there any way that we could reuse that to describe a sidecar? @danehans or @arkodg do you have any thoughts on what the ideal API surface would look like for an extension deployed as a sidecar?

[arkodg]

assuming sidecar here, is sidecar in the gateway pod, if it looks like a backendRef, you could route back to the Gateway Service and have the sidecar listen on a different port, and other implementations like Envoy Gateway could use the custom Backend Resource to backendRef to route via UDS

[robscott]

Yep, sidecar on the gateway pod, that's a good idea.

[ahg-g]

ok, so we should be good with a service reference here, right?

[arkodg]

@ahg-g something that looks like https://github.com/kubernetes-sigs/gateway-api/blob/50cf145b0dd1849ebd03c5866a92797862f23efe/apis/v1/object_reference_types.go#L96 should solve the Service case and also allow for other custom backend types

[k8s-ci-robot]

@ahg-g: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-gateway-api-inference-extension-verify-main	5e51daf	link	true	/test pull-gateway-api-inference-extension-verify-main
pull-gateway-api-inference-extension-test-unit-main	5e51daf	link	true	/test pull-gateway-api-inference-extension-test-unit-main

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