feat: ✨ HPA: Horizontal Pod Autoscaler

Horizontal Pod Autoscaling (HPA) is a Kubernetes feature that automatically adjusts the number of running pods in a deployment or replica set based on real-time metrics such as CPU utilization or custom metrics. This ensures that your application can scale out to handle increased load and scale in when demand decreases, optimizing resource usage and performance. (Command to perform CPU tests: kubectl run -it fortio --rm --image=fortio/fortio -- load -qps 800 -t 120s -c 70 "http://go-http-app-service/healthz")

Makefile

@@ -9,7 +9,6 @@ create-kind-cluster:
 
 deploy:
 	kubectl apply -f k8s
-	sleep 3
 	$(MAKE) port-forward
 
 delete:
@@ -18,14 +17,14 @@ delete:
 redeploy:
 	$(MAKE) delete
 	$(MAKE) deploy
-	sleep 3
 	$(MAKE) port-forward
 
 port-forward: 
+	sleep 4
 	kubectl port-forward svc/go-http-app-service 8000:80
 
 install-metrics-components:
 	kubectl apply -f k8s/metrics-server.yaml
 	kubectl wait --namespace kube-system \
     --for=condition=available deployment/metrics-server \
-    --timeout=200s
+    --timeout=60s

k8s/deployment.yaml

@@ -17,7 +17,7 @@ spec:
     spec: 
       containers:
         - name: go-http-app
-          image: wesleywillians/hello-go:v5.5 # Probe on port /healthz (+ readiness check: if app is up < 10s it will fail. This way, readiness will only be "ready" when the pod is healthy)
+          image: wesleywillians/hello-go:v9.6 
           resources:
             requests:
               cpu: "0.03"

k8s/hpa.yaml

@@ -0,0 +1,18 @@
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: go-http-app-hpa
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: go-http-app 
+  minReplicas: 2
+  maxReplicas: 10
+  metrics:
+  - type: Resource
+    resource:
+      name: cpu
+      target:
+        type: Utilization
+        averageUtilization: 35