# mongo-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongo-deployment
  labels:
    app: mongodb
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mongodb # let deployment know which pod for this deployment
  template: # configuration for pods
    metadata:
      labels:
        app: mongodb # each pod has a unique name, but pods can share the same label
    spec:
      containers: # containers in a pod, usually add one container per pod
      - name: mongodb
        image: mongo:5.0 # pull image from Docker Hub
        ports:
        - containerPort: 27017
        env:
        - name: MONGO_INITDB_ROOT_USERNAME
          valueFrom:
            secretKeyRef:
              name: mongo-secret # secret name
              key: mongo-user
        - name: MONGO_INITDB_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mongo-secret # secret name
              key: mongo-password
        

Internal service, has an internal IP

# mongo-service.yaml
apiVersion: v1
kind: Service # type
metadata:
  name: mongo-service # service name
spec:
  selector:
    app: mongodb # connect pod through label
  ports:
    - protocol: TCP
      port: 27017 # service port
      targetPort: 27017 # pod port
        

# mongo-express-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mongo-express-deployment
  labels:
    app: mongo-express
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mongo-express
  template:
    metadata:
      labels:
        app: mongo-express
    spec:
      containers:
      - name: mongo-express
        image: mongo-express
        ports:
        - containerPort: 8081
        env:
        - name: ME_CONFIG_MONGODB_ADMINUSERNAME
          valueFrom:
            secretKeyRef:
              name: mongo-secret # secret name
              key: mongo-user
        - name: ME_CONFIG_MONGODB_ADMINPASSWORD
          valueFrom:
            secretKeyRef:
              name: mongo-secret # secret name
              key: mongo-password
        - name: ME_CONFIG_MONGODB_SERVER
          valueFrom:
            configMapKeyRef:
              name: mongo-configmap # configMap name
              key: database_url
        

External service, has an internal IP and an external IP

# mongo-express-service.yaml
apiVersion: v1
kind: Service # type
metadata:
  name: mongo-express-service # service name
spec:
  selector:
    app: mongo-express
  type: LoadBalancer
  ports:
    - protocol: TCP
      port: 8081 # service port
      targetPort: 8081 # pod port
      nodePort: 30000 # prot for external IP address, must be between 30000-32767
        

# mongo-secret.yaml
apiVersion: v1
kind: Secret # type
metadata:
  name: mongo-secret # name
type: Opaque # default, for arbitrary key-value pairs
data:
  mongo-user: bW9uZ291c2Vy # echo -n 'username' | base64
  mongo-password: bW9uZ29wYXNzd29yZA== # echo -n 'password' | base64
        

# mongo-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mongo-configmap
data:
  database_url: mongo-service # service name
        

# minikube on Mac
minikube service mongo-express-service
http://192.168.64.4:30000

kubectl port-forward svc/mongo-express-service 8080:8081
http://127.0.0.1:8080
        

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