KEP-5229: Asynchronous API calls during scheduling (#5249)

* KEP-5229: Asynchronous API calls during scheduling

* Change KEP approvers, add API calls categorization section and adjust the goals

* Extend API calls categorization section

* Apply comments

* Move not selected proposals to Alternative section. Add design details with three detailed proposals

* Update toc

* Fill PRR

* Update toc

* Add risks section and apply small fixes

* Refine some sections and apply the comments

* Apply comments and move two proposals to alternatives

* Improve wording

* Apply comments around custom plugins

* Update toc

Author: macsko

keps/prod-readiness/sig-scheduling/5229.yaml

@@ -0,0 +1,3 @@
+kep-number: 5229
+beta:
+  approver: "@wojtek-t"

keps/sig-scheduling/5229-asynchronous-api-calls-during-scheduling/README.md

@@ -0,0 +1,34 @@
+title: Asynchronous API calls during scheduling
+kep-number: 5229
+authors:
+  - "@macsko"
+owning-sig: sig-scheduling
+status: implementable
+creation-date: 2025-04-08
+reviewers:
+  - dom4ha
+  - sanposhiho
+approvers:
+  - dom4ha
+  - sanposhiho
+
+stage: beta
+
+latest-milestone: "v1.34"
+
+# The milestone at which this feature was, or is targeted to be, at each stage.
+milestone:
+  beta: "v1.34"
+
+# The following PRR answers are required at alpha release
+# List the feature gate name and the components for which it must be enabled
+feature-gates:
+  - name: SchedulerAsyncAPICalls
+    components:
+      - kube-scheduler
+disable-supported: true
+
+metrics:
+  - async_api_call_execution_total
+  - async_api_call_duration_seconds
+  - pending_async_api_calls