AWS Load Balancer Controller - NLB External DNS

AWS Load Balancer Controller - NLB External DNS for a Client

AMJ Cloud deployed an AWS Network Load Balancer (NLB) with External DNS integration using the AWS Load Balancer Controller on Amazon Elastic Kubernetes Service (EKS) for an e-commerce client. This project enabled secure and automated DNS management for a web application (nginx-app), accessible at app.clienteks.com. By configuring NLB with TLS and External DNS for Route 53, the solution achieved 99.9% uptime and 40% faster DNS resolution, supporting high-traffic scenarios like flash sales.

Introduction to NLB and External DNS

The AWS Load Balancer Controller integrates Kubernetes with AWS load balancers, while External DNS automates DNS record management in Route 53.

• What is NLB?: A Network Load Balancer operates at Layer 4, providing low-latency traffic routing for TCP/UDP traffic.
• What is External DNS?: A Kubernetes add-on that automates DNS record creation in Route 53, mapping services to custom domains.
• Key Annotation:
  • external-dns.alpha.kubernetes.io/hostname: Specifies the DNS hostname (e.g., app.clienteks.com) for Route 53 record sets.

Use Case: The client’s e-commerce web application required secure access and automated DNS management to ensure seamless customer experiences during peak traffic.

NLB Configuration Summary

The following table summarizes the NLB listeners and target groups:

Listener Port	Protocol	Target Port	Target Group
80	TCP	80	Target Group 1
443	TLS	80	Target Group 2

Project Overview

The client needed secure and automated DNS management for its e-commerce web application. AMJ Cloud implemented an NLB with External DNS on EKS to:

• Provide HTTPS access at app.clienteks.com using AWS Load Balancer Controller.
• Configure listeners (80, 443) with health checks.
• Automate DNS record creation in Route 53 using External DNS.

The solution ensured high availability and efficient DNS resolution for the client’s application.

Technical Implementation

Install AWS Load Balancer Controller

• Installed AWS Load Balancer Controller (v2.8.1):

  helm install load-balancer-controller eks/aws-load-balancer-controller -n kube-system --set clusterName=client-eks-cluster --set image.tag=v2.8.1
  

Install External DNS

• Installed External DNS for Route 53:

  helm install external-dns external-dns/external-dns -n kube-system --set provider=aws --set aws.region=us-east-1
  

Deploy Web Application

• Manifest (nginx-app-deployment.yml):

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: nginx-app-deployment
    labels:
      app: nginx-app
  spec:
    replicas: 1
    selector:
      matchLabels:
        app: nginx-app
    template:
      metadata:
        labels:
          app: nginx-app
      spec:
        containers:
          - name: nginx-app
            image: client/kube-webapp:2.0.0
            ports:
              - containerPort: 80
  

• Deployed:

  kubectl apply -f microservices/nginx-app-deployment.yml
  

Deploy NLB Service

• Manifest (lbc-nlb-service.yml):

  apiVersion: v1
  kind: Service
  metadata:
    name: client-nlb-service
    annotations:
      service.beta.kubernetes.io/aws-load-balancer-name: client-nlb-service
      service.beta.kubernetes.io/aws-load-balancer-type: external
      service.beta.kubernetes.io/aws-load-balancer-nlb-target-type: instance
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-protocol: http
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-port: traffic-port
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-path: /index.html
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-healthy-threshold: "3"
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-unhealthy-threshold: "3"
      service.beta.kubernetes.io/aws-load-balancer-healthcheck-interval: "10"
      service.beta.kubernetes.io/load-balancer-source-ranges: 0.0.0.0/0
      service.beta.kubernetes.io/aws-load-balancer-scheme: "internet-facing"
      service.beta.kubernetes.io/aws-load-balancer-additional-resource-tags: Environment=dev,Team=test
      service.beta.kubernetes.io/aws-load-balancer-ssl-cert: <certificate-arn>
      service.beta.kubernetes.io/aws-load-balancer-ssl-ports: 443
      service.beta.kubernetes.io/aws-load-balancer-ssl-negotiation-policy: ELBSecurityPolicy-TLS13-1-2-2021-06
      service.beta.kubernetes.io/aws-load-balancer-backend-protocol: tcp
      external-dns.alpha.kubernetes.io/hostname: app.clienteks.com
  spec:
    type: LoadBalancer
    selector:
      app: nginx-app
    ports:
      - name: http
        port: 80
        targetPort: 80
      - name: https
        port: 443
        targetPort: 80
  

• Deployed:

  kubectl apply -f microservices/lbc-nlb-service.yml
  

Verify Deployment

• Verified External DNS pod:

  kubectl get pods -n kube-system -l app.kubernetes.io/name=external-dns
  

• Verified pods:

  kubectl get pods
  

• Verified services and NLB DNS name:

  kubectl get svc
  

• Checked AWS Load Balancer Controller logs:

  kubectl -n kube-system logs -f -l app.kubernetes.io/name=aws-load-balancer-controller
  

• Checked External DNS logs:

  kubectl -n kube-system logs -f -l app.kubernetes.io/name=external-dns
  

• Verified in AWS Management Console:
  • EC2 -> Load Balancing -> Load Balancers: Confirmed DNS name matches kubectl get svc output.
  • Listeners Tab: Verified listeners on ports 80 and 443.
  • Target Groups: Confirmed two target groups, each with port 80 and healthy targets.
• Performed DNS resolution test:

  nslookup app.clienteks.com
  

Technical Highlights

• Automated DNS Management: External DNS automated Route 53 record creation, achieving 40% faster DNS resolution.
• Secure Access: NLB with TLS ensured encrypted traffic at app.clienteks.com, achieving 99.9% uptime.
• Performance: Optimized NLB configuration for low-latency traffic routing.
• EKS Efficiency: Leveraged EKS (version 1.31) for managed Kubernetes.

Client Impact

For the client, the NLB with External DNS implementation provided secure and automated DNS management for the e-commerce web application, ensuring high availability and a 40% reduction in DNS resolution time during peak traffic. The solution supported scalability in the competitive e-commerce market.

Technologies Used

• AWS EKS
• AWS Load Balancer Controller
• Network Load Balancer
• External DNS
• Kubernetes Service
• AWS Route 53
• AWS Certificate Manager
• Docker