https://tech.cloudmt.co.kr/2022/03/11/http-traffic-based-autoscaling-with-keda/

CLUSTER_NAME=<CLUSTER_NAME>
AWS_ACCOUNT_ID=$(aws sts get-caller-identity --query Account --output text)

helm repo add kedacore <https://kedacore.github.io/charts>
helm repo update
helm install keda kedacore/keda --namespace keda --create-namespace
helm install http-add-on kedacore/keda-add-ons-http --namespace keda

helm repo add eks <https://aws.github.io/eks-charts>
helm repo update eks
helm install aws-load-balancer-controller eks/aws-load-balancer-controller \\
  -n kube-system \\
  --set clusterName=$CLUSTER_NAME \\
  --set serviceAccount.create=false \\
  --set serviceAccount.name=aws-load-balancer-controller

public_a=$(aws ec2 describe-subnets --filters "Name=tag:Name,Values=skills-public-subnet-a" --query "Subnets[].SubnetId[]" --region ap-northeast-2 --output text)
public_b=$(aws ec2 describe-subnets --filters "Name=tag:Name,Values=skills-public-subnet-b" --query "Subnets[].SubnetId[]" --region ap-northeast-2 --output text)
private_a=$(aws ec2 describe-subnets --filters "Name=tag:Name,Values=skills-private-subnet-a" --query "Subnets[].SubnetId[]" --region ap-northeast-2 --output text)
private_b=$(aws ec2 describe-subnets --filters "Name=tag:Name,Values=skills-private-subnet-b" --query "Subnets[].SubnetId[]" --region ap-northeast-2 --output text)

public_subnet_name=("$public_a" "$public_b")
private_subnet_name=("$private_a" "$private_b")

for name in "${public_subnet_name[@]}"
do
    aws ec2 create-tags --resources $name --tags Key=kubernetes.io/role/elb,Value=1
done

for name in "${private_subnet_name[@]}"
do
    aws ec2 create-tags --resources $name --tags Key=kubernetes.io/role/internal-elb,Value=1
done

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: keda
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
            - containerPort: 80

kubectl apply -f deployment.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
  namespace: keda
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: ClusterIP

kubectl apply -f service.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: keda-ingress
  namespace: keda
  annotations:
    alb.ingress.kubernetes.io/load-balancer-name: keda-alb
    alb.ingress.kubernetes.io/scheme: internet-facing
    alb.ingress.kubernetes.io/target-type: ip
    alb.ingress.kubernetes.io/listen-ports: '[{"HTTP": 80}]'
    alb.ingress.kubernetes.io/healthcheck-path: /
    alb.ingress.kubernetes.io/healthcheck-interval-seconds: "5"
    alb.ingress.kubernetes.io/healthcheck-timeout-seconds: "3"
    alb.ingress.kubernetes.io/healthy-threshold-count: "3"
    alb.ingress.kubernetes.io/unhealthy-threshold-count: "2"
    alb.ingress.kubernetes.io/target-group-attributes: deregistration_delay.timeout_seconds=30
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: keda-add-ons-http-interceptor-proxy
                port:
                  number: 8080