deploy.yml

# check out all Kubernetes commands here:
# https://kubernetes.io/docs/reference/kubectl/cheatsheet/

# -----------------------------------------------------------*
# implies the use of kubernetes 1.7
# use apps/v1beta2 for kubernetes 1.8
# -----------------------------------------------------------*
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nodejs-demo-app
  namespace: default
spec:
  replicas: 4                     # this is number of pods
  selector:
    matchLabels:
      app: nodejs-demo-app
  template:
    metadata:
      labels:
        app: nodejs-demo-app
    spec:
      # Kubernetes run docker pull pseudo/your-image:latest under the hood
      # Image field in Kubernetes resources is simply the docker image to run.
      containers:
      - name: nodejs-demo-app
        # pulling image from my DockerHub
        image: yanndocker/nodejs-demo:latest
        # using if not present works well with images that has tag
        # if you image is tag:lastest - use Always otherwise you
        # wouldn't get the fresh version of your image
        imagePullPolicy: Always
        # -----------------------------------------------------------*
        # It is a good practice to declare resource requests and 
        # limits for both memory and cpu for each container. 
        # This helps to schedule the container to a node that has 
        # available resources for your Pod, and also so that your 
        # Pod does not use resources that other Pods needs
        # -----------------------------------------------------------*
        resources:
          limits:
            memory: 64Mi
            cpu: "250m"
          requests:
            memory: 32Mi
            cpu: "200m"
        # specify the container port
        ports:
        - containerPort: 30002

    # -----------------------------------------------------------*
    # If your image is hosted in a private docker hub repo, 
    # you need to specify an image pull secret in the spec field.
    # -----------------------------------------------------------*
    # spec:
    #   containers:
    #   - name: app
    #     image: pseudo/your-image:latest
    #   imagePullSecrets:
    #   - name: dockerhub-credential
    # -----------------------------------------------------------*
---
apiVersion: v1
kind: Service
metadata:
  name: nodejs-demo-app-entrypoint
  namespace: default
spec:
  # -----------------------------------------------------------*
  # if you're using service type NodePort. To access you app
  # and test it locally you need to listen on local port.
  # you can do that by forwarding a local port to Service target 
  # port with name <my-service-name>
  # e.g -- 
  # kubectl port-forward service/nodejs-demo-app-entrypoint 3000:443
  # -----------------------------------------------------------*
  # type: NodePort
  type: LoadBalancer
  selector:
    app: nodejs-demo-app
  # The range of valid ports in kubernetes is 30000-32767
  ports:
    # - protocol: TCP
    #   port: 30002
    #   targetPort: 30002
    #   nodePort: 30002
    # -----------------------------------------------------------*
    # this block is for when you wanna use the type load balancer
    # on your local computer or else where
    # -----------------------------------------------------------*
    - name: http
      protocol: TCP
      port: 80             # this is service port 80
      targetPort: 30002
      # nodePort: 30003      # this is for when using type: NodePort
    - name: https
      protocol: TCP
      port: 443            # this is service port 443
      targetPort: 30002
      # nodePort: 30004      # this is for when using type: NodePort