Unable to access Spring Boot microservice exposed via nginx ingress controller on Kubernetes cluster running on AWS

Question

I have spun up a 3 node Kubernetes cluster (version: 1.5.8) on AWS using the kube-up.sh script following this walkthrough:

https://ryaneschinger.com/blog/building-a-kubernetes-cluster-on-aws/

I'm able to successfully access the cluster and view the UI. Output of kubectl cluster-info command:

I wrote a simple Spring Boot microservice:

@RestController
public class AddCustomerController {

    private static final String template = "Customer %s is added.";

    @RequestMapping("/addcustomer")
    public Message addcustomer(@RequestParam(value="name") String name) {

        //Retrieve the hostname of the "node"/"container"
        String hostname = null;
        try {
            hostname = InetAddress.getLocalHost().getHostName();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        return new Message(ThreadLocalRandom.current().nextLong(),
                            String.format(template, name),
                            hostname);
    }
}

and packaged it in a Docker container after the Gradle build and am able to successfully use it locally. I have pushed the image to DockerHub.

FROM openjdk:8-jdk-alpine
VOLUME /tmp
ADD build/libs/*.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

Now I'm using Helm Charts to deploy this application to Kubernetes.

Deployment descriptor:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: add-customer-deployment
spec:
  replicas: 3
  template:
    metadata:
      name: add-customer-microservice
      labels:
        app: add-customer
    spec:
      containers:
      - image: {{ .Values.dockerHubUsername }}/add-customer-microservice:latest
        name: add-customer-microservice
        imagePullPolicy: Always
        ports:
        - containerPort: 8080

Service descriptor:

apiVersion: v1
kind: Service
metadata:
  name: add-customer-service
spec:
  selector:
    app: add-customer
  ports:
    - port: 1000
      protocol: TCP
      targetPort: 8080
      name: access-port
  type: NodePort

I have followed the same procedure for 3 other similar Spring Boot microservices.

Ingress descriptor:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: quantiphi-poc-ingress-dns
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
    - host: crud.qdatalabs.com
      http:
        paths:
        - path: /service1
          backend:
            serviceName: add-customer-service
            servicePort: 1000
        - path: /service1/*
          backend:
            serviceName: add-customer-service
            servicePort: 1000
        - path: /service2
          backend: 
            serviceName: get-customer-service
            servicePort: 2000
        - path: /service2/*
          backend:
            serviceName: get-customer-service
            servicePort: 2000
        - path: /service3
          backend: 
            serviceName: update-customer-service
            servicePort: 3000
        - path: /service3/*
          backend:
            serviceName: update-customer-service
            servicePort: 3000
        - path: /service4
          backend: 
            serviceName: delete-customer-service
            servicePort: 4000
        - path: /service4/*
          backend:
            serviceName: delete-customer-service
            servicePort: 4000

First I install the nginx controller on my cluster using the Helm Charts:

helm install --name my-release stable/nginx-ingress

Then I install my Chart using:

helm install folder-conataining-helm-chart/

Then I point the alias of crud.qdatalabs.com (Type A) from Route53 to the ELB spawned by the Ingress resource.

The URL crud.qdatalabs.com/healthz is giving 200 OK response

When I try to access the microservices using the URL crud.qdatalabs.com/service1/addcustomer?name=starman

I'm treated with the WhiteLabel Error Page:

I think I have made some configuration error, but can't put my finger on it. Please help me with any direction. I'll be happy to provide more details. Thank you.

Answer 1

As I stated in Setting up a Kuberentes cluster with HTTP Load balancing ingress for RStudio and Shiny results in error pages , the most likely problem you have is that when you go with this ingress you attached your URI is different then with direct accesc ( /service1/ vs / ) so your app is lost and has no content for that uri.

With Nginx Ingress Controller you can use ingress.kubernetes.io/rewrite-target: / annotation to mitigate this and make sure that / is accessed even when there is a subfolder in the ingress path.

So, you either need to use proper rewrite annotation or support the path you use in the ingress inside your service.