From ae4ef6e992c9a1c57e22e4d83c448ea06e969262 Mon Sep 17 00:00:00 2001
From: Jerome Meyer <jerome.meyer@fmr.com>
Date: Thu, 11 Jan 2024 05:19:41 -0500
Subject: [PATCH] Update HorizontalPodAutoscaler API to autoscaling/v2 (#153)

---
 .../templates/hpa.yaml                        | 20 ++++++++++-------
 .../charts/spire-server/templates/hpa.yaml    | 22 +++++++++++--------
 charts/spire/templates/_spire-lib.tpl         | 14 ++++++++++++
 3 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/charts/spire/charts/spiffe-oidc-discovery-provider/templates/hpa.yaml b/charts/spire/charts/spiffe-oidc-discovery-provider/templates/hpa.yaml
index fcacb3f..0a6dfa3 100644
--- a/charts/spire/charts/spiffe-oidc-discovery-provider/templates/hpa.yaml
+++ b/charts/spire/charts/spiffe-oidc-discovery-provider/templates/hpa.yaml
@@ -1,5 +1,5 @@
 {{- if .Values.autoscaling.enabled }}
-apiVersion: autoscaling/v2beta1
+apiVersion: {{ include "spire-lib.autoscalingVersion" . }}
 kind: HorizontalPodAutoscaler
 metadata:
   name: {{ include "spiffe-oidc-discovery-provider.fullname" . }}
@@ -14,16 +14,20 @@ spec:
   minReplicas: {{ .Values.autoscaling.minReplicas }}
   maxReplicas: {{ .Values.autoscaling.maxReplicas }}
   metrics:
-    {{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
-    - type: Resource
-      resource:
-        name: cpu
-        targetAverageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
-    {{- end }}
     {{- if .Values.autoscaling.targetMemoryUtilizationPercentage }}
     - type: Resource
       resource:
         name: memory
-        targetAverageUtilization: {{ .Values.autoscaling.targetMemoryUtilizationPercentage }}
+        target:
+          type: Utilization
+          averageUtilization: {{ .Values.autoscaling.targetMemoryUtilizationPercentage }}
+    {{- end }}
+    {{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
     {{- end }}
 {{- end }}
diff --git a/charts/spire/charts/spire-server/templates/hpa.yaml b/charts/spire/charts/spire-server/templates/hpa.yaml
index 921abf6..4c1c41c 100644
--- a/charts/spire/charts/spire-server/templates/hpa.yaml
+++ b/charts/spire/charts/spire-server/templates/hpa.yaml
@@ -1,5 +1,5 @@
 {{- if .Values.autoscaling.enabled }}
-apiVersion: autoscaling/v2beta1
+apiVersion: {{ include "spire-lib.autoscalingVersion" . }}
 kind: HorizontalPodAutoscaler
 metadata:
   name: {{ include "spire-server.fullname" . }}
@@ -9,7 +9,7 @@ metadata:
 spec:
   scaleTargetRef:
     apiVersion: apps/v1
-    kind: Deployment
+    kind: StatefulSet
     name: {{ include "spire-server.fullname" . }}
   minReplicas: {{ .Values.autoscaling.minReplicas }}
   {{- if and (eq .Values.dataStore.sql.databaseType "sqlite3") .Values.autoscaling.enabled (gt (int .Values.autoscaling.maxReplicas) 1) }}
@@ -17,16 +17,20 @@ spec:
   {{- end }}
   maxReplicas: {{ .Values.autoscaling.maxReplicas }}
   metrics:
-    {{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
-    - type: Resource
-      resource:
-        name: cpu
-        targetAverageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
-    {{- end }}
     {{- if .Values.autoscaling.targetMemoryUtilizationPercentage }}
     - type: Resource
       resource:
         name: memory
-        targetAverageUtilization: {{ .Values.autoscaling.targetMemoryUtilizationPercentage }}
+        target:
+          type: Utilization
+          averageUtilization: {{ .Values.autoscaling.targetMemoryUtilizationPercentage }}
+    {{- end }}
+    {{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
     {{- end }}
 {{- end }}
diff --git a/charts/spire/templates/_spire-lib.tpl b/charts/spire/templates/_spire-lib.tpl
index 71c2ad9..614e05e 100644
--- a/charts/spire/templates/_spire-lib.tpl
+++ b/charts/spire/templates/_spire-lib.tpl
@@ -318,3 +318,17 @@ priorityClassName: {{ .Values.priorityClassName }}
 priorityClassName: system-cluster-critical
 {{- end }}
 {{- end }}
+
+{{/*
+Use autoscaling/v2 (Kubernetes 1.23 and newer) or autoscaling/v2beta2 (Kubernetes 1.12-1.25) based on cluster capabilities.
+Anything lower has an incompatible API.
+*/}}
+{{- define "spire-lib.autoscalingVersion" -}}
+{{- if (.Capabilities.APIVersions.Has "autoscaling/v2") }}
+{{- print "autoscaling/v2" }}
+{{- else if (.Capabilities.APIVersions.Has "autoscaling/v2beta2") }}
+{{- print "autoscaling/v2beta2" }}
+{{- else }}
+{{- fail "Unsupported autoscaling API version" }}
+{{- end }}
+{{- end }}