How to fix headless service not found in Kubernetes

kubectl get svc -n your-namespace

apiVersion: v1
kind: Service
metadata:
  name: my-db
  namespace: default
spec:
  clusterIP: None  # This makes it headless
  selector:
    app: my-db
  ports:
  - port: 5432
    targetPort: 5432

kubectl apply -f service.yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: my-db
spec:
  serviceName: my-db  # Must match service name
  selector:
    matchLabels:
      app: my-db  # Must match service selector
  template:
    metadata:
      labels:
        app: my-db

kubectl exec -it my-db-0 -- nslookup my-db.default.svc.cluster.local

kubectl get pods --show-labels