Kubernetes

Configurations YAML File

Deployment

 - kind: Deployment
   apiVersion: apps/v1
   metadata:
     name: app-deployment
     namespace: app-ns
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: my-app
     template:
       metadata:
         labels:
           app: my-app
       spec:
         volumes:
           - name: app-secrets-volume
             secret:
               secretName: my-secret
         containers:
           - image: ${CONTAINER_REGISTRY_URL}/${IMAGE_NAME}:${IMAGE_TAG}
             name: my-app
             ports:
                - containerPort: 8080
             envFrom:
               - configMapRef:
                  name: app-config
               - secretRef:
                  name: my-secrets
             env:
               - name: CUSTOM_ENV_VAR
                 value: "soon_to_come"
             volumeMounts:
               - name: app-secrets-volume
                 mountPath: /opt/my-app/secrets-volume
                 readOnly: true
         restartPolicy: Always
         terminationGracePeriodSeconds: 30

Service

 - kind: Service
   apiVersion: v1
   metadata:
     name: app-service
     namespace: app-ns
   spec:
     ports:
       - port: 8080
         targetPort: 8080
     selector:
       app: my-app

Use the following option to make the service Headless, this is good when each of the pods has state and the state could be different between them. This exposes each pods ip through a DNS lookup.

 Service.spec.clusterIP: None

ConfigMap

 # ConfigMap Configuration
 - kind: ConfigMap
   apiVersion: v1
   metadata:
     name: app-config
     namespace: app-ns
   data:
     CONFIG_TEMP: soon-to-come

Templates

To use templates, allows for values to be injected.

 kind: Template
 apiVersion: template.openshift.io/v1
 metadata:
   name: my-project
   annotations:
     description: "This is my project"
     tags: "java,project,other"

 objects:
  ...

 # Template Parameters
 parameters:
   - description: "This param is an example"
     required: true
     name: PARAM_1
   - description: "To use the param use the dollar sign followed by braces."
     required: true
     name: IMAGE_NAME

Then to use the params inline, use

 ${PARAM_1}