mongo-deployment.yml

apiVersion: apps/v1
kind: Deployment
metadata: 
  name: mongodb-deployment
  labels:
    app: mongodb
spec: 
  replicas: 1
  selector: 
    matchLabels: 
      app: mongodb
  template:
    metadata:
      labels:
        app: mongodb
    spec:
      containers:
      - name: mongodb
        image: mongo
        ports: 
        - containerPort: 27017
        env: 
        - name: MONGO_INITDB_ROOT_USERNAME
          valueFrom:
            secretKeyRef:
              name: mongodb-secret
              key: mongo-root-username
        - name: MONGO_INITDB_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mongodb-secret
              key: mongo-root-password    
---
apiVersion: v1
kind: Service
metadata:
  name: mongodb-service
spec:
  selector:
    app: mongodb
  ports:
  - protocol: TCP
    port: 27017
    targetPort: 27017