external-name-service.yaml

# This example exposes a REST service that is external to the cluster
# to the pods within the cluster.  Notice, there are no label selectors.  In this
# case we use the type ExternalName and provide the URI to the external service
# in the externalName field.  The pods would just look up the service
# just like any service - using the service name. See the source code of the API 
# in the random-quote-api directory.
# 
# 1. Deploy the service and deployment.
#
#  kubectl create -f external-name-service.yml'
# 
# 2. Deploy busybox
# 
#  kubectl run busybox --image busybox:1.28 -- sleep 100000
# 
# 3. Get the name of the busybox pod and get access to its shell
#
#  kubectl get pods 
#  kubectl exec -ti busybox-pod-name -- sh
#
# 4. From the shell run: 
# 
#  nslookup random-quote-service
#  nslookup quotes.rest

kind: Service
apiVersion: v1
metadata:
  #when looking up this service using the service name, the cluster
  #DNS will return a CNAME record with the value quotes.rest
  name:  random-quote-service
spec:
  type:  ExternalName
  externalName: quotes.rest #must be a valid DNS name.  e.g. you can't do https://quotes.rest/qod
---
kind: Service
apiVersion: v1
metadata:
  name:  random-quote
spec:
  selector:
    name: random-quote-api
  type:  LoadBalancer
  ports:
  - name:  name-of-the-port
    port:  80
    targetPort:  8000 
---
# This is the deployment and pod template for the API that will
# integrate with the random-quote-service
apiVersion: apps/v1
kind: Deployment
metadata:
  name:  random-quote-api
  labels:
    name:  random-quote-api
spec:
  replicas: 1
  selector:
    matchLabels:
      name: random-quote-api
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      labels:
        name:  random-quote-api
    spec:
      containers:
      - image:  architechbootcamp/random-quote:1.0.0
        imagePullPolicy: Always
        name:  random-quote-api
        resources:
          requests:
            cpu: "20m"
            memory: "55M"
          limits:
            cpu: "20m"
            memory: "55M"
        ports:
        - containerPort: 8000
        env:
        #Notice the value of the environment variable
        #is the name of the service defined above
        - name: RANDOM_QUOTE_SERVICE
          value: random-quote-service
      restartPolicy: Always