I have 2 deployment, 2 respective node port services, both targeted to port 80 in my EKS cluster runs in AWS environment.

My Terraform templates are like as follows:

Resource: Kubernetes Ingress Class Manifest

# File: 01. ingress_class.tf

resource "kubernetes_ingress_class_v1" "ingress_class_default" {
  depends_on = [helm_release.loadbalancer_controller]
  metadata {
    name = "ingress-class"
    # annotations = {
    #   "ingressclass.kubernetes.io/is-default-class" = "true"
    # }
  }  
  spec {
    controller = "ingress.k8s.aws/alb"
  }
}

Kubernetes API Deployment Manifest

# File: 02. api.tf

resource "kubernetes_deployment_v1" "api" {
  metadata {
    name = "api-deployment"
    labels = {
      app = "api"
    }
  } 
 
  spec {
    replicas = 1

    selector {
      match_labels = {
        app = "api"
      }
    }

    template {
      metadata {
        labels = {
          app = "api"
        }
      }

      spec {
        container {
          image = "my_image"
          name  = "api"
          env {
            name = "BASE_CLIENT_URL"
            value = "http://client"
          }
          port {
            container_port = 80
          }
        }
      }
    }
  }
}

Kubernetes Client Deployment Manifest

# File: 03. client.tf

resource "kubernetes_deployment_v1" "client" {
  metadata {
    name = "client-deployment"
    labels = {
      app = "client"
    }
  } 
 
  spec {
    replicas = 1

    selector {
      match_labels = {
        app = "client"
      }
    }

    template {
      metadata {
        labels = {
          app = "client"
        }
      }

      spec {
        container {
          image = "my_image"
          name  = "client"
          
          env {
            name = "NEXT_PUBLIC_API_URL"
            value = "http://api"
          }
          env {
            name = "NEXTAUTH_SECRET"
            value = "SDKLFKasjdaeirpiwiKJKIOOIJDasdfd"
          }
          env {
            name = "NEXTAUTH_URL"
            value = "http://api/api/auth"
          }
          
          port {
            container_port = 80
          }
          }
        }
      }
    }
}

Kubernetes Service Manifest API Nodeport

# Filename: 04. api-nodeport.tf

resource "kubernetes_service_v1" "api_np_service" {
  metadata {
    name = "api-nginx-nodeport-service"
    annotations = {
      "alb.ingress.kubernetes.io/healthcheck-path" = "/api"
    }    
  }
  spec {
    selector = {
      app = kubernetes_deployment_v1.api.spec.0.selector.0.match_labels.app
    }
    port {
      name        = "http"
      port        = 80
      target_port = 80
    }
    type = "NodePort"
  }
}

Kubernetes Service Manifest Client Nodeport

# Filename: 05. client-nodeport.tf

resource "kubernetes_service_v1" "client_np_service" {
  metadata {
    name = "client-nginx-nodeport-service"
    annotations = {
      "alb.ingress.kubernetes.io/healthcheck-path" = "/"
    }    
  }
  spec {
    selector = {
      app = kubernetes_deployment_v1.client.spec.0.selector.0.match_labels.app
    }
    port {
      name        = "http"
      port        = 80
      target_port = 80
    }
    type = "NodePort"
  }
}

Kubernetes Service Manifest Load Balancer

# Filename: 06. ingress-service.tf

resource "kubernetes_ingress_v1" "ingress" {
  metadata {
    name = "ingress-service"
    annotations = {
      # Load Balancer Name
      "alb.ingress.kubernetes.io/load-balancer-name" = "ingress-service"
      # Ingress Core Settings
      "alb.ingress.kubernetes.io/scheme" = "internet-facing"
      # Health Check Settings
      "alb.ingress.kubernetes.io/healthcheck-protocol" =  "HTTP"
      "alb.ingress.kubernetes.io/healthcheck-port" = "traffic-port"
      #Important Note:  Need to add health check path annotations in service level if we are planning to use multiple targets in a load balancer    
      "alb.ingress.kubernetes.io/healthcheck-interval-seconds" = 15
      "alb.ingress.kubernetes.io/healthcheck-timeout-seconds" = 5
      "alb.ingress.kubernetes.io/success-codes" = 200
      "alb.ingress.kubernetes.io/healthy-threshold-count" = 2
      "alb.ingress.kubernetes.io/unhealthy-threshold-count" = 2
    }    
  }

  spec {
    ingress_class_name = "ingress-class" # IngressClass
    default_backend {
      service {
        name = kubernetes_service_v1.client_np_service.metadata[0].name
        port {
          number = 80
        }
      }
    }

    rule {
      http {
        
        path {
          backend {
            service {
              name = kubernetes_service_v1.api_np_service.metadata[0].name
              port {
                number = 80
              }
            }
          }
          path = "/api/v1/"
          path_type = "Prefix"
        }

      }
    }
  }
}

After successful deployment I can access them via browser:

1. Client: http://ingress-service-38383838.us-east-1.elb.amazonaws.com/
2. API: http://ingress-service-38383838.us-east-1.elb.amazonaws.com/api/v1

But my Client app failed to access the API service to fetch data.

I don’t understand what I am missing?