From 129b7d119eb5a26b045e36a96272e5ad932a3ba9 Mon Sep 17 00:00:00 2001
From: Brandon Pinske <brandon@pinske.info>
Date: Wed, 18 Nov 2020 13:22:34 -0700
Subject: [PATCH] Support Keda Autoscaling

Keda autoscaling is exclusive with regular hpa scaling. If both are set to true, keda takes precedence.
---
 charts/ingress-nginx/Chart.yaml               |  2 +-
 .../templates/controller-hpa.yaml             |  4 +++
 .../templates/controller-keda.yaml            | 33 +++++++++++++++++
 charts/ingress-nginx/values.yaml              | 35 +++++++++++++++++++
 4 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 charts/ingress-nginx/templates/controller-keda.yaml

diff --git a/charts/ingress-nginx/Chart.yaml b/charts/ingress-nginx/Chart.yaml
index eca4f9546..9c39a6f98 100644
--- a/charts/ingress-nginx/Chart.yaml
+++ b/charts/ingress-nginx/Chart.yaml
@@ -1,6 +1,6 @@
 apiVersion: v1
 name: ingress-nginx
-version: 3.10.1
+version: 3.11.0
 appVersion: 0.41.2
 home: https://github.com/kubernetes/ingress-nginx
 description: Ingress controller for Kubernetes using NGINX as a reverse proxy and load balancer
diff --git a/charts/ingress-nginx/templates/controller-hpa.yaml b/charts/ingress-nginx/templates/controller-hpa.yaml
index 4923cf8d2..c2ad10530 100644
--- a/charts/ingress-nginx/templates/controller-hpa.yaml
+++ b/charts/ingress-nginx/templates/controller-hpa.yaml
@@ -1,4 +1,6 @@
 {{- if and .Values.controller.autoscaling.enabled (or (eq .Values.controller.kind "Deployment") (eq .Values.controller.kind "Both")) -}}
+{{- if not .Values.controller.keda.enabled }}
+
 apiVersion: autoscaling/v2beta2
 kind: HorizontalPodAutoscaler
 metadata:
@@ -34,3 +36,5 @@ spec:
 {{- toYaml . | nindent 2 }}
   {{- end }}
 {{- end }}
+{{- end }}
+
diff --git a/charts/ingress-nginx/templates/controller-keda.yaml b/charts/ingress-nginx/templates/controller-keda.yaml
new file mode 100644
index 000000000..7c391de9d
--- /dev/null
+++ b/charts/ingress-nginx/templates/controller-keda.yaml
@@ -0,0 +1,33 @@
+{{- if .Values.controller.keda.enabled }}
+# https://keda.sh/docs/
+
+apiVersion: {{ .Values.controller.keda.apiVersion }}
+kind: ScaledObject
+metadata:
+  labels:
+    {{- include "ingress-nginx.labels" . | nindent 4 }}
+    app.kubernetes.io/component: controller
+  name: {{ include "ingress-nginx.controller.fullname" . }}
+
+spec:
+  scaleTargetRef:
+    deploymentName: {{ include "ingress-nginx.controller.fullname" . }}
+  pollingInterval: {{ .Values.controller.keda.pollingInterval }}
+  cooldownPeriod: {{ .Values.controller.keda.cooldownPeriod }}
+  minReplicaCount: {{ .Values.controller.keda.minReplicas }}
+  maxReplicaCount: {{ .Values.controller.keda.maxReplicas }}
+  triggers:
+{{- with .Values.controller.keda.triggers }}
+{{ toYaml . | indent 2 }}
+{{ end }}
+  advanced:
+    restoreToOriginalReplicaCount: {{ .Values.controller.keda.restoreToOriginalReplicaCount }}
+{{- if .Values.controller.keda.behavior }}
+    horizontalPodAutoscalerConfig:
+      behavior:
+{{ with .Values.controller.keda.behavior -}}
+{{ toYaml . | indent 8 }}
+{{ end }}
+
+{{- end }}
+{{- end }}
diff --git a/charts/ingress-nginx/values.yaml b/charts/ingress-nginx/values.yaml
index f62f466a1..7e2e54c72 100644
--- a/charts/ingress-nginx/values.yaml
+++ b/charts/ingress-nginx/values.yaml
@@ -273,6 +273,7 @@ controller:
       cpu: 100m
       memory: 90Mi
 
+  # Mutually exclusive with keda autoscaling
   autoscaling:
     enabled: false
     minReplicas: 1
@@ -291,6 +292,40 @@ controller:
   #       type: AverageValue
   #       averageValue: 10000m
 
+  # Mutually exclusive with hpa autoscaling
+  keda:
+    apiVersion: "keda.sh/v1alpha1"
+  # apiVersion changes with keda 1.x vs 2.x
+  # 2.x = keda.sh/v1alpha1
+  # 1.x = keda.k8s.io/v1alpha1
+    enabled: false
+    minReplicas: 1
+    maxReplicas: 11
+    pollingInterval: 30
+    cooldownPeriod: 300
+    restoreToOriginalReplicaCount: false
+    triggers: []
+ #     - type: prometheus
+ #       metadata:
+ #         serverAddress: http://<prometheus-host>:9090
+ #         metricName: http_requests_total
+ #         threshold: '100'
+ #         query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))
+
+    behavior: {}
+ #     scaleDown:
+ #       stabilizationWindowSeconds: 300
+ #       policies:
+ #       - type: Pods
+ #         value: 1
+ #         periodSeconds: 180
+ #     scaleUp:
+ #       stabilizationWindowSeconds: 300
+ #       policies:
+ #       - type: Pods
+ #         value: 2
+ #         periodSeconds: 60
+
   ## Enable mimalloc as a drop-in replacement for malloc.
   ## ref: https://github.com/microsoft/mimalloc
   ##