I am doing this exercise on my vagrant built bare metal cluster on a windows machine.

Was able to successfully run the app.

But I am not able to connect to the database to see the data, say from mongo db compass.

What should be the user id or password for this?

After a bit of research, I used the following steps to get into the mongo container and verify the data. But I want to connect to the database using a client like compass.

Used the following command to find where the mongo db backend database pod is deployed.

vagrant@kmasterNew:~/GuestBookMonog$ kubectl get pods -o wide
NAME                       READY   STATUS    RESTARTS   AGE     IP              NODE          NOMINATED NODE   READINESS GATES
frontend-848d88c7c-95db6   1/1     Running   0          4m51s   192.168.55.11   kworkernew2   <none>           <none>
mongo-75f59d57f4-klmm6     1/1     Running   0          4m54s   192.168.55.10   kworkernew2   <none>           <none>

Then ssh into that node and did

docker container ls 

to find the mongo db container

It looks something like this. I removed irrelevant data.

CONTAINER ID   IMAGE                    COMMAND                  CREATED          STATUS          PORTS     NAMES
1ba3d05168ca   dc77715107a9             "docker-entrypoint.s…"   53 minutes ago   Up 53 minutes             k8s_mongo_mongo-75f59d57f4-5tw5b_default_eeddf81b-8dde-4c3e-8505-e08229f97c8b_0      

A reference from SO

docker exec -it 1ba3d05168ca bash

Another reference from SO in this context

mongo
show dbs
use guestbook
show collections
db.messages.find()

Finally I was able to verify the data

> db.messages.find()
{ "_id" : ObjectId("6097f6c28088bc17f61bdc32"), "message" : ",message1" }
{ "_id" : ObjectId("6097f6c58088bc17f61bdc33"), "message" : ",message1,message2" }

But the question is how can I see this data from mongo db compass? I am exposing the both the frontend as well as the backend services using NodePort type. You can see them below.

The follow are the k8s manifest files for the deployment that I got from the above example.

Front end deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: frontend
  labels:
    app.kubernetes.io/name: guestbook
    app.kubernetes.io/component: frontend
spec:
  selector:
    matchLabels:
      app.kubernetes.io/name: guestbook
      app.kubernetes.io/component: frontend
  replicas: 1
  template:
    metadata:
      labels:
        app.kubernetes.io/name: guestbook
        app.kubernetes.io/component: frontend
    spec:
      containers:
      - name: guestbook
        image: paulczar/gb-frontend:v5
        # image: gcr.io/google-samples/gb-frontend:v4
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
        env:
        - name: GET_HOSTS_FROM
          value: dns
        ports:
        - containerPort: 80

The front end service.

apiVersion: v1
kind: Service
metadata:
  name: frontend
  labels:
    app.kubernetes.io/name: guestbook
    app.kubernetes.io/component: frontend
spec:
  # if your cluster supports it, uncomment the following to automatically create
  # an external load-balanced IP for the frontend service.
  # type: LoadBalancer
  type: NodePort
  ports:
  - port: 80
    nodePort: 30038
  # - targetPort: 80
  #   port: 80
  #   nodePort: 30008

  selector:
    app.kubernetes.io/name: guestbook
    app.kubernetes.io/component: frontend

Next the mongo db deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongo
  labels:
    app.kubernetes.io/name: mongo
    app.kubernetes.io/component: backend
spec:
  selector:
    matchLabels:
      app.kubernetes.io/name: mongo
      app.kubernetes.io/component: backend
  replicas: 1
  template:
    metadata:
      labels:
        app.kubernetes.io/name: mongo
        app.kubernetes.io/component: backend
    spec:
      containers:
      - name: mongo
        image: mongo:4.2
        args:
          - --bind_ip
          - 0.0.0.0
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
        ports:
        - containerPort: 27017

Finally the mongo service

apiVersion: v1
kind: Service
metadata:
  name: mongo
  labels:
    app.kubernetes.io/name: mongo
    app.kubernetes.io/component: backend
spec:
  ports:
  - port: 27017
    targetPort: 27017
    nodePort: 30068
  type: NodePort
  selector:
    app.kubernetes.io/name: mongo
    app.kubernetes.io/component: backend