Kubernetes-101-02_hellogopher_v2.yaml

apiVersion: apps/v1 #Which version of the Kubernetes API you're using to create this object
kind: Deployment # What kind of object you want to create [deployment, service etc]
metadata: # Data that helps uniquely identify the object, including a name string, UID, and optional namespace
  name: hellogopher
  namespace: hellogopher
spec: #  What state you desire for the object
  selector: # Define what selectors the Deployment uses to find the PODS that are related to it
    matchLabels: # matchLabels is a map of {key,value} pairs. 
      app: hellogopher
  replicas: 1 # Tells the deployment to run 1 pod 
  template: # When creating new pods, this template will be used
    metadata:
      labels: # Labels used when searching / managing deployments
        app: hellogopher
    spec:
      containers:
      - name: hellogopher # Name of the Container
        image: programmingpercy/hellogopher:5.0 # Important, to not use latest tag as it will try DOckerhub then
        imagePullPolicy: IfNotPresent # Will only pull from DockerHub if not present already in Local docker
        env:
          # Use secret in real usage
        - name: DATABASE_USERNAME
          valueFrom:
            configMapKeyRef: # We specify that we want to use a ConfigMap to fetch the value
              name: database-configs # the name of the ConfigMap
              key: DATABASE_USERNAME # The key value used in the configmap
        - name: DATABASE_PASSWORD
          value: password
        - name: DATABASE_NAME
          valueFrom:
            configMapKeyRef: # We specify that we want to use a ConfigMap to fetch the value
              name: database-configs # the name of the ConfigMap
              key: DATABASE_NAME # The key value used in the configmap
        ports: # Ports to Expose
        - containerPort: 8080
        readinessProbe:
          initialDelaySeconds: 5 # Time before starting to Probe status
          timeoutSeconds: 1 # Time to wait before timeout
          # HTTP probe
          httpGet:
            path: / # the path we use to probe
            port: 8080
        livenessProbe:
          initialDelaySeconds: 5 # Time before starting to Probe status
          timeoutSeconds: 1 # Time to wait before timeout
          failureThreshold: 3 # How many times it can fail before restarting
          # HTTP probe
          httpGet:
            path: / # the path we use to probe
            port: 8080