Review Project

Let’s review the resources.

Namespace

We’ll create a namespace for the app resources:

.kubes/resources/shared/namespace.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: demo-<%= Kubes.env %>
  labels:
    app: demo

Notice, the <%= Kubes.env %>. Kubes adds the env to the namespace by default. You can change this with the init --namespace option.

Deployment

The web/deployment.yaml file is a little more interesting:

.kubes/resources/web/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web
  labels:
    role: web
spec:
  replicas: 1
  selector:
    matchLabels:
      role: web
  template:
    metadata:
      labels:
        role: web
    spec:
      containers:
      - name: web
        image: <%= built_image %>

Notice the <%= built_image %>. Kubes processes the YAML files with ERB templating and replaces these tags. The built_image is a kubes helper method that refers to the latest Docker image built by Kubes. This spares you updating the image manually.

Base Folder

Also let’s check the files in the base folder.

.kubes/resources/base/all.yaml

metadata:
  namespace: demo-<%= Kubes.env %>

.kubes/resources/base/deployment.yaml

metadata:
  labels:
    app: demo
spec:
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo

The base folder files are processed first as a part of Kubes Layering. This allows you to define common fields and keep your code DRY.

The all.yaml means all resources will use the demo namespace. The deployment.yaml adds common labels to all deployment resource kinds.

Service Resource

Next, let’s look at service.yaml

.kubes/resources/web/service.yaml

apiVersion: v1
kind: Service
metadata:
  name: web
  labels:
    role: web
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: <%= dockerfile_port %>
  selector:
    role: web
  type: ClusterIP

The dockerfile_port helper returns the EXPOSE port in the Dockerfile. This spares you updating this manually, you only have to update the Dockerfile.

Next, we’ll deploy the app.