I have created my own k8s cluster using Kubeadm with two Ubuntu virtual servers - one master and one worker node. I also deployed a Springboot app with MongoDB persistence and it works absolutely fine. Below are the nodes in my k8s cluster

Below are the contents of my yaml file which creates storage class, persistence volume, persistence volume claim, mongo deployment and mongo service

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
   name: local-storage
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
reclaimPolicy: Retain
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mongo-pv
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  storageClassName: local-storage
  hostPath:
    path: "/home/moviepopcorn/mongodb/data"
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values: 
          - node1
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mongo-pvc
spec:
  volumeName: mongo-pv
  volumeMode: Filesystem
  storageClassName: local-storage
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongo
  labels:
    app: mongo
spec:
   selector:
      matchLabels:
         app: mongo
   template:
      metadata:
         labels:
            app: mongo
      spec:
        containers:
        - name: mongo
          image: mongo:4.4.11
          ports:
          - containerPort: 27017 
          volumeMounts:
          - name: mongo-persistent-storage
            mountPath: /home/moviepopcorn/mongodb/data
        volumes:
          - name: mongo-persistent-storage
            persistentVolumeClaim:
              claimName: mongo-pvc
---
apiVersion: v1
kind: Service
metadata:
  name: mongo-service
spec:
  selector:
    app: mongo
  ports:
    - protocol: TCP 
      port: 27017
      targetPort: 27017

Data stored from my Springboot into mongodb is not retained once I reboot the nodes in my k8s cluster. Could you please help me understand on what mistake I am doing?

CodePudding user response：

May you have updated the PVC mount path and due to that mongo not aware of where to store or save the data

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: mongo
  name: mongo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mongo
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: mongo
    spec:
      containers:
      - image: mongo
        name: mongo
        args: ["--dbpath","/data/db"]
        livenessProbe:
          exec:
            command:
              - mongo
              - --disableImplicitSessions
              - --eval
              - "db.adminCommand('ping')"
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 6
        readinessProbe:
          exec:
            command:
              - mongo
              - --disableImplicitSessions
              - --eval
              - "db.adminCommand('ping')"
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 6
        env:
        - name: MONGO_INITDB_ROOT_USERNAME
          valueFrom:
            secretKeyRef:
              name: mongo-creds
              key: username
        - name: MONGO_INITDB_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mongo-creds
              key: password
        volumeMounts:
        - name: "mongo-data-dir"
          mountPath: "/data/db"
      volumes:
      - name: "mongo-data-dir"
        persistentVolumeClaim:
          claimName: "pvc"

Try the above example or check the arg and mount path for reference.