Help about exposing service through dns record

General Discussions
1

I installed kubernetes on virtual machine servers.(to test it before installing bare-metal) and created a cluster that has 1 master and 3 worker nodes. I installed calico default configuration as a network plugin.
After reading the k8s documentation, I thought that I can expose to internal network using a dns name using pod → service → ingress.

I installed ingress-nginx and I am using this as an ingress class. I created deployment, service and ingress using following yaml content.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  namespace: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: testcontainers/helloworld
        ports:
        - containerPort: 8099

--------
apiVersion: v1
kind: Service
metadata:
  name: my-app-service
  namespace: my-app
spec:
  selector:
    app: my-app
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8099
  type: ClusterIP

-------
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-app-ingress
  namespace: my-app
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: k8stest.myorganization.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-app-service
            port:
              number: 80

After this configuration I thought that i can simply access the service using dns name k8stest.myogranization.com. (dns is defined in the internal dns server in my organization)

After reading some content bare-metal configuration requires loadbalancer and i used metallb loadbalancer using following

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
name: default
namespace: metallb-system
spec:
addresses:

  • node1Ipaddress -node3IpAddress
    autoAssign: true

apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
name: default
namespace: metallb-system
spec:
ipAddressPools:

  • default

I just want to create a dns record, expose the containers using this dns record in my local network. I can ping k8stest.myorganization.com.

I could not find the reason why I cannot access the service. What is the missing part? How can I trace the errors?

What is the guide to find root causes of this kind of problems?

Thanks in advance.

Ihsan

Cluster information:

1 master and 3 worker nodes
NAME STATUS ROLES AGE VERSION
k8s-master01-staging Ready control-plane 83d v1.31.1
k8s-worker-01-staging Ready 83d v1.31.1
k8s-worker-02-staging Ready 83d v1.31.1
k8s-worker-03-staging Ready 83d v1.31.1

Kubernetes version:

Client Version: v1.31.1
Kustomize Version: v5.4.2
Server Version: v1.31.0

Cloud being used: (put bare-metal if not on a public cloud)
Installation method: using documentation.

Host OS: ubuntu 24.04
CNI and version:
CRI and version: