Network Load Balancer with the NGINX Ingress Controller on Amazon EKS always returns a 503 error

Question

All files referenced are included below. I am trying to create a NGINX proxy to serve my back-end and front-end with the same domain.

Nginx runs successfully, I can tell because I get a 404 error from nginx when I hit the root url given by kubectl get ingress .

When I hit the url/hello endpoint, however, I get a 503 Service Temporarily Unavailable error from Nginx.

Has anyone encountered this error?

Here is the yaml file for my kubectl create -f command:

kind: Service
apiVersion: v1
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
  annotations:
    # by default the type is elb (classic load balancer).
    service.beta.kubernetes.io/aws-load-balancer-type: nlb
spec:
  # this setting is to make sure the source IP address is preserved.
  externalTrafficPolicy: Local
  type: LoadBalancer
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
  ports:
    - name: http
      port: 80
      targetPort: http
    # - name: https
    #   port: 443
    #   targetPort: https

---

kind: Ingress
apiVersion: networking.k8s.io/v1beta1
metadata:
  name: test-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - http:
      paths:
      - path: /hello
        backend:
          serviceName: go-hello
          servicePort: 8080

---

kind: Pod
apiVersion: v1
metadata:
  name: go-hello
  labels:
    app: go-hello
spec:
  containers:
    - name: go-hello
      image: docker.io/chsclarke11/test-go

---

kind: Service
apiVersion: v1
metadata:
  name: go-hello-service
spec:
  selector:
    app: go-hello
  ports:
    - port: 8080 # Default port for image   

here is the Dockerfile for the go-hello app:

FROM golang:1.12-alpine

RUN apk add --no-cache git

# Set the Current Working Directory inside the container
WORKDIR /app

RUN go mod download

COPY . .

# Build the Go app
RUN go build -o main

# This container exposes port 8080 to the outside world
EXPOSE 8080

# Run the binary program produced by `go install`
CMD ["./main"]

Here is the go-hello mock application:

package main

import (
    "fmt"
    "net/http"
)

func main() {
    fmt.Printf("starting server at http://localhost:8080")
    http.HandleFunc("/", HelloServer)
    http.ListenAndServe(":8080", nil)
}

func HelloServer(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello, %s!", r.URL.Path[1:])
}

Answer 1

In Ingress definition you have specified wrong backend service name: go-hello which is not compatible with service name you created for backend - g o-hello-service .

Also for the future you can get a 503 error from nginx when basic-auth is enable in the Ingress and the annotation nginx.ingress.kubernetes.io/auth-secret is referencing a non-existing secret.

You can also add the missing secret or removing all basic-auth annotations from the Ingress can resolve this situation.