feat(chart): add support for autoscaling behavior in HPA (#27990)

Squash-merged by litellm-agent from FabrizioCafolla's PR.

deploy/charts/litellm-helm/templates/hpa.yaml

@@ -12,6 +12,10 @@ spec:
     name: {{ include "litellm.fullname" . }}
   minReplicas: {{ .Values.autoscaling.minReplicas }}
   maxReplicas: {{ .Values.autoscaling.maxReplicas }}
+  {{- if .Values.autoscaling.behavior }}
+  behavior:
+    {{- toYaml .Values.autoscaling.behavior | nindent 4 }}
+  {{- end }}
   metrics:
     {{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
     - type: Resource

deploy/charts/litellm-helm/tests/hpa_tests.yaml

@@ -0,0 +1,36 @@
+suite: "hpa with behavior"
+templates:
+  - hpa.yaml
+tests:
+  - it: "renders behavior when set"
+    set:
+      autoscaling.enabled: true
+      autoscaling.behavior:
+        scaleUp:
+          stabilizationWindowSeconds: 60
+          policies:
+            - type: Pods
+              value: 2
+              periodSeconds: 60
+        scaleDown:
+          stabilizationWindowSeconds: 90
+          policies:
+            - type: Pods
+              value: 1
+              periodSeconds: 60
+    asserts:
+      - isKind: { of: HorizontalPodAutoscaler }
+      - equal: { path: spec.behavior.scaleUp.stabilizationWindowSeconds, value: 60 }
+      - equal: { path: spec.behavior.scaleDown.stabilizationWindowSeconds, value: 90 }
+
+---
+suite: "hpa without behavior"
+templates:
+  - hpa.yaml
+tests:
+  - it: "does not render behavior when not set"
+    set:
+      autoscaling.enabled: true
+    asserts:
+      - isKind: { of: HorizontalPodAutoscaler }
+      - isNull: { path: spec.behavior }

deploy/charts/litellm-helm/values.yaml

@@ -184,6 +184,7 @@ autoscaling:
   maxReplicas: 100
   targetCPUUtilizationPercentage: 80
   # targetMemoryUtilizationPercentage: 80
+  # behavior: {}
 
 # Autoscaling with keda is mutually exclusive with hpa
 keda: