Kubernetes stateful mongodb: What is right string or how to connect to mongodb of running istance of statefulset which has service also attached?

Question

Here is my config of YAML (all PV, Statefulset, and Service get created fine no issues in that). Tried a bunch of solution for connection string of Kubernetes mongo but didn't work any.

Kubernetes version (minikube): 1.20.1

Storage for config: NFS (working fine, tested)

OS: Linux Mint 20

YAML CONFIG:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: auth-pv
spec:
  capacity:
    storage: 250Mi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  storageClassName: manual
  nfs:
    path: /nfs/auth
    server: 192.168.10.104
---
apiVersion: v1
kind: Service
metadata:
  name: mongo
  labels:
    name: mongo
spec:
  ports:
    - port: 27017
      targetPort: 27017
  selector:
    role: mongo
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mongo
spec:
  selector:
    matchLabels:
      app: mongo
  serviceName: mongo
  replicas: 1
  template:
    metadata:
      labels:
        app: mongo
    spec:
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongo
          image: mongo
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-persistent-storage
              mountPath: /data/db
  volumeClaimTemplates:
    - metadata:
        name: mongo-persistent-storage
      spec:
        storageClassName: manual
        accessModes: ["ReadWriteMany"]
        resources:
          requests:
            storage: 250Mi

Answer 1

I have found few issues in your configuration file. In your service manifest file you use

  selector:
    role: mongo

But in your statefull set pod template you are using

labels:
        app: mongo

One more thing you should use ClusterIP:None to use the headless service which is recommended for statefull set, if you want to access the db using dns name.

Answer 2

To all viewers, working YAML is below

right connection string is: mongodb://mongo:27017/<dbname>

apiVersion: v1
kind: PersistentVolume
metadata:
  name: auth-pv
spec:
  capacity:
    storage: 250Mi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  storageClassName: manual
  nfs:
    path: /nfs/auth
    server: 192.168.10.104
---
apiVersion: v1
kind: Service
metadata:
  name: mongo
  labels:
    name: mongo
spec:
  ports:
    - port: 27017
      targetPort: 27017
  selector:
    app: mongo
  clusterIP: None  
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mongo
spec:
  selector:
    matchLabels:
      app: mongo
  serviceName: mongo
  replicas: 1
  template:
    metadata:
      labels:
        app: mongo
    spec:
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongo
          image: mongo
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-persistent-storage
              mountPath: /data/db
  volumeClaimTemplates:
    - metadata:
        name: mongo-persistent-storage
      spec:
        storageClassName: manual
        accessModes: ["ReadWriteMany"]
        resources:
          requests:
            storage: 250Mi