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MiniKube

Kubernetes must be installed and running on your local machine. You can use Minikube or Kind for this purpose. If you are using Docker Desktop, make sure Kubernetes is enabled in the settings.

The concepts and the Postgres and Gateway manifests are covered in Hands-on 5 — Orchestration.

TO DO

All microservices should be published in the same kubernetes cluster. Create a setup file for each microservice, in its own k8s folder, eg.:

📁 api/
└── 📁 account-service/
    └── 📁 k8s/
        └── YAML k8s.yaml

Where k8s.yaml is the setup file for the microservice. The setup file should include the following resources:

  • Secrets;
  • ConfigMap;
  • Deployment, and;
  • Service.

Every microservice must have its own setup file:

  • account-service;
  • auth-service;
  • gateway-service;
  • product-service, and;
  • order-service.

Run all services in the same cluster and verify they are healthy. You may use a local Kubernetes setup or a cloud provider such as AWS, Azure, or Google Cloud Platform. Demonstrate that all services are running in the same cluster by recording a short video.

Example: account-service

A single k8s.yaml can hold several resources, separated by ---. The account service reads its database connection from the ConfigMap (host, port, database) and the Secret (username, password), and connects to the postgres Service from Hands-on 5.

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apiVersion: v1
kind: Secret
metadata:
  name: account-secrets
type: Opaque
data:
  DATABASE_USERNAME: c3RvcmU=   # echo -n "store" | base64
  DATABASE_PASSWORD: c3RvcmU=

---

apiVersion: v1
kind: ConfigMap
metadata:
  name: account-configmap
data:
  DATABASE_HOST: postgres       # name of the Postgres Service
  DATABASE_PORT: "5432"
  DATABASE_DB: store

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: account
spec:
  replicas: 1
  selector:
    matchLabels:
      app: account
  template:
    metadata:
      labels:
        app: account
    spec:
      containers:
        - name: account
          image: <your-dockerhub-user>/account-service:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8080
          envFrom:                # every key becomes an environment variable
            - configMapRef:
                name: account-configmap
            - secretRef:
                name: account-secrets
          resources:
            requests:
              memory: "256Mi"
              cpu: "250m"
            limits:
              memory: "512Mi"
              cpu: "500m"

---

apiVersion: v1
kind: Service
metadata:
  name: account
spec:
  type: ClusterIP               # internal: only the gateway is exposed
  selector:
    app: account
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8080

kubectl apply -f ./k8s/k8s.yaml
kubectl get secrets,configmaps
kubectl get deployments,pods,services
kubectl logs deployment/account

Only the gateway is exposed outside the cluster (type: LoadBalancer); the other services use type: ClusterIP and are reached by the gateway through their Service name (e.g. http://account:8080).

Minikube

  • Images: the cluster must be able to pull your images. Push them to Docker Hub, or load a local image with minikube image load <image> and keep imagePullPolicy: IfNotPresent (with Always, Kubernetes tries the registry and fails).
  • Gateway access: a LoadBalancer Service stays <pending> on Minikube. Run minikube tunnel in another terminal, or open it with minikube service gateway.