app-deployment.yaml

apiVersion: apps/v1
kind: Deployment # mentions this is a Deployment
metadata:
    name: go-app # name of Deployment
spec:
    replicas: 2 # creates 2 replicated Pods
    selector:
        matchLabels:
            app: go-app # defines how the Deployment finds which Pods to manage
    template:
        metadata:
            labels:
                app: go-app # specifies that the Pods are to be named as go-app
        spec: # specification for each Pod .This block indicates that the Pods run one container 'go-app-container', which runs the jeshocarmel/ip_location_mapper dockerhub image .
            containers:
                - name: go-app-container # name of the container running inside the Pod
                  image: jeshocarmel/ip_location_mapper # image to deployed in the container
                  imagePullPolicy: Always # pull image from the repository (dockerhub) always
                  ports:
                    - containerPort: 8080 # run on port 8080
                  livenessProbe: # To check the health of the Pod
                    httpGet:
                      path: /health
                      port: 8080
                      scheme: HTTP
                    initialDelaySeconds: 5
                    periodSeconds: 15
                    timeoutSeconds: 5
                  readinessProbe: # To check if the Pod is ready to serve traffic or not
                    httpGet:
                      path: /readiness
                      port: 8080
                      scheme: HTTP
                    initialDelaySeconds: 5
                    timeoutSeconds: 1   
                  env: # list of env variables passed to the app
                    - name: IPSTACK_API_KEY # IPSTACK_API_KEY is used inside the app
                      valueFrom:
                        secretKeyRef:
                            name: app-secret # name of the secret
                            key: apikey # import the value of 'apikey' from app-secret
                            
                    - name: REDIS_URL # REDIS_URL is the hostname for the redis cluster 
                      valueFrom:
                        configMapKeyRef:
                            name: app-configmap # name of the config-map
                            key: redis-service # import the value of 'redis-service' from app-configmap

                    - name: REDIS_PASSWORD # REDIS_PASSWORD is used by the app to authenticate with the redis host
                      valueFrom:
                        secretKeyRef:
                            name: app-secret # name of the secret
                            key: redis-password # import the value of 'redis-password' from app-secret
---
kind: Service # mentions this is a service
apiVersion: v1
metadata:
  name: go-app-service # name of service
spec:
  type: NodePort # service type to be NodePort
  ports:
  - name: http
    port: 80 # serve on port 80
    targetPort: 8080 # reach to port 8080 of all the Pods in the selector block
    nodePort: 30000 # use port 30000 as nodePort
    
  selector:
      app: go-app # The set of Pods with name'go-app' is targeted by this Service