kubernetes - How to deploy a single instance mongodb with persistant volume using NFS

Question

I have a microservice that is working on my laptop. However, I am using docker compose. I am working to deploy to a kubernetes cluster which I have already set up. I am stuck on making data persistent. E.g here is my mongodb in docker-compose

systemdb:
    container_name: system-db
    image: mongo:4.4.1
    restart: always
    ports:
      - '9000:27017'
    volumes:
      - ./system_db:/data/db
    networks:
      - backend

Since it is an on premise solution, I went with an NFS server. I have created a Persistent Volume and Persistent Volume Claim (pvc-nfs-pv1) which seem to work well when testing with nginx. However, I don't know how to deploy a mongodb statefulset to use the pvc. I am not implementing a replicaset.

Here is my yaml:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mongod
spec:
  serviceName: mongodb-service
  replicas: 1
  selector:
    matchLabels:
      role: mongo
  template:
    metadata:
      labels:
        role: mongo
        environment: test
    spec:
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongod-container
          image: mongo
          resources:
            requests:
              cpu: "0.2"
              memory: 200Mi
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: pvc-nfs-pv1
              mountPath: /data/db
  volumeClaimTemplates:
  - metadata:
      name: pvc-nfs-pv1
       annotations:
         volume.beta.kubernetes.io/storage-class: "standard"
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 500Mi

How do i do it?

Answer 1

volumeClaimTemplates are used for dynamic volume provisioning. So you're defining one volume claim template which will be used to create a PersistentVolumeClaim for each pod.

The volumeClaimTemplates will provide stable storage using PersistentVolumes provisioned by a PersistentVolume Provisioner

So for your use case you would need to create storageclass with nfs provisioner. NFS Subdir external provisioner is an automatic provisioner that use your existing and already configured NFS server to support dynamic provisioning of Kubernetes Persistent Volumes via Persistent Volume Claims. Persistent volumes are provisioned as ${namespace}-${pvcName}-${pvName}.

Here`s an example how to define storage class:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: fuseim.pri/ifs # or choose another name, must match deployment's env PROVISIONER_NAME'
parameters:
  pathPattern: "${.PVC.namespace}/${.PVC.annotations.nfs.io/storage-path}" # waits for nfs.io/storage-path annotation, if not specified will accept as empty string.
  onDelete: delete