ALB Ingress - Target Type - IP mode #18

 

Step-01: Introduction

• alb.ingress.kubernetes.io/target-type specifies how to route traffic to pods.
• You can choose between instance and ip
• Instance Mode: instance mode will route traffic to all ec2 instances within cluster on NodePort opened for your service.
• IP Mode: ip mode is required for sticky sessions to work with Application Load Balancers.

Step-02: Ingress Manifest - Add target-type

• File Name: 04-ALB-Ingress-target-type-ip.yml

    # Target Type: IP
    alb.ingress.kubernetes.io/target-type: ip   

Step-03: Deploy all Application Kubernetes Manifests and Verify

# Deploy kube-manifests
kubectl apply -f kube-manifests/

# Verify Ingress Resource
kubectl get ingress

# Verify Apps
kubectl get deploy
kubectl get pods

# Verify NodePort Services
kubectl get svc

Verify Load Balancer & Target Groups

• Load Balancer - Listeneres (Verify both 80 & 443)
• Load Balancer - Rules (Verify both 80 & 443 listeners)
• Target Groups - Group Details (Verify Health check path)
• Target Groups - Targets (Verify all 3 targets are healthy)
• PRIMARILY VERIFY - TARGET GROUPS which contain thePOD IPs instead of WORKER NODE IP with NODE PORTS

# List Pods and their IPs
kubectl get pods -o wide

Verify External DNS Log

# Verify External DNS logs
kubectl logs -f $(kubectl get po | egrep -o 'external-dns[A-Za-z0-9-]+')

Verify Route53

• Go to Services -> Route53
• You should see Record Sets added for
  • target-type-ip-501.stacksimplify.com

Step-04: Access Application using newly registered DNS Name

Perform nslookup tests before accessing Application

• Test if our new DNS entries registered and resolving to an IP Address

# nslookup commands
nslookup target-type-ip-501.stacksimplify.com 

Access Application using DNS domain

# Access App1
http://target-type-ip-501.stacksimplify.com /app1/index.html

# Access App2
http://target-type-ip-501.stacksimplify.com /app2/index.html

# Access Default App (App3)
http://target-type-ip-501.stacksimplify.com 

Step-05: Clean Up

# Delete Manifests
kubectl delete -f kube-manifests/

## Verify Route53 Record Set to ensure our DNS records got deleted
- Go to Route53 -> Hosted Zones -> Records 
- The below records should be deleted automatically
  - target-type-ip-501.stacksimplify.com 

why we define cluster IP service in Target IP mode?
No specific reason, so you can have it as nodeport or clusterip both are same,
Bcaz request coming to application load balancer will directly go to pod ip


why we define service itself in Target IP mode?
you need service have the ingress created target group and register the target inside that.
and target group register IP directly