Unhandled exception. Npgsql.NpgsqlException (0x80004005): Failed to connect to 10.152.183.151:5432

I can't connect my .net 6 application (from docker image) to a postgresql database from kubernetes (microk8s).

Unhandled exception. Npgsql.NpgsqlException (0x80004005): Failed to connect to 10.152.183.151:5432
 ---> System.Net.Sockets.SocketException (111): Connection refused
   at Npgsql.Internal.NpgsqlConnector.Connect(NpgsqlTimeout timeout)
   at Npgsql.Internal.NpgsqlConnector.Connect(NpgsqlTimeout timeout)
   at Npgsql.Internal.NpgsqlConnector.RawOpen(SslMode sslMode, NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken, Boolean isFirstAttempt)
   at Npgsql.Internal.NpgsqlConnector.<Open>g__OpenCore|215_1(NpgsqlConnector conn, SslMode sslMode, NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken, Boolean isFirstAttempt)

These are my services:

NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)       AGE
web-app-service   NodePort  10.152.183.40   <none>      80:31069/TCP   23m
pgsql-service   ClusterIP   10.152.183.151   <none>     5432/TCP    23m

Here is my yml file (the values in the secret file are correct) :

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app-deployment
  namespace: exo-kubernetes
spec:
  replicas: 1
  selector:
    matchLabels:
    app: web-app
  template:
    metadata:
    labels:
        app: web-app
    spec:
    containers:
    - image: my-image:latest
        name: web-app
        ports:
        - containerPort: 80
        resources:
        requests:
            memory: "64Mi"
            cpu: "250m"
        limits:
            memory: "128Mi"
            cpu: "500m"

---

apiVersion: v1
kind: Service
metadata:
  name: web-app-service
  namespace: exo-kubernetes
spec:
  selector:
    app: web-app-deployment
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pgsql-deployment
  namespace: exo-kubernetes
spec:
  replicas: 1
  selector:
    matchLabels:
    app: pgsql
  template:
    metadata:
    labels:
        app: pgsql
    spec:
    containers:
    - image: postgres:15.3
        name: pgsql
        env:
        - name: POSTGRES_USER
        valueFrom:
            secretKeyRef:
            name: db-access
            key: USER
        - name: POSTGRES_PASSWORD
        valueFrom:
            secretKeyRef:
            name: db-access
            key: PASSWORD
        - name: POSTGRES_DB
        valueFrom:
            secretKeyRef:
            name: db-access
            key: DB_NAME
        ports:
        - containerPort: 5432
        resources:
        requests:
            memory: "512Mi"
            cpu: "600m"
        limits:
            memory: "2Gi"
            cpu: "1200m"
        volumeMounts:
        - mountPath: /var/lib/postgresql/data
            name: pgsql-vm
    volumes:
        - name: pgsql-vm


---

apiVersion: v1
kind: Service
metadata:
  name: pgsql-service
  namespace: exo-kubernetes
spec:
  selector:
    app: pgsql-deployment
  ports:
  - port: 5432
    targetPort: 5432

---

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: web-app-ing
  namespace: exo-kubernetes
spec:
  rules:
  - http:
    paths:
    - path: /
        pathType: Prefix
        backend:
        service:
            name: web-app-service
            port:
            number: 80

and my ConnectionStrings :

"DbConnection": "Host=pgsql-service;Port=5432;Database=Kubernetes;UserID=kubernetes;Password=kubernetes;"

If anyone has a solution, I'd be delighted.

I've tried several solutions like port modification or connectionStrings but without any conclusive result.

The selector label that you're using in postgres service (app: pgsql-deployment) should be present in your postgre's Deployment manifest. In your case, it's missing. It should be like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pgsql-deployment
  namespace: exo-kubernetes
  labels: # add this field
    app: pgsql-deployment # add the same label as the one present in service
spec:
  replicas: 1
  selector:
    matchLabels:
    app: pgsql
  template:
    metadata:
    labels:
      app: pgsql
    spec:
    containers:
    - image: postgres:15.3
        name: pgsql
        env:
        - name: POSTGRES_USER
        valueFrom:
            secretKeyRef:
            name: db-access
            key: USER
        - name: POSTGRES_PASSWORD
        valueFrom:
            secretKeyRef:
            name: db-access
            key: PASSWORD
        - name: POSTGRES_DB
        valueFrom:
            secretKeyRef:
            name: db-access
            key: DB_NAME
        ports:
        - containerPort: 5432
        resources:
        requests:
            memory: "512Mi"
            cpu: "600m"
        limits:
            memory: "2Gi"
            cpu: "1200m"
        volumeMounts:
        - mountPath: /var/lib/postgresql/data
            name: pgsql-vm
    volumes:
        - name: pgsql-vm