Deploy Application With Istio Gateway and Virtual Service¶

Now that we have a good understanding of traffic management in Istio, let's deploy a simple application using traffic management API resources such as Gateway and Virtual Service.

Step 1: View Istio Proxy Configuration¶

Note down the current proxy configuration:

# Retrieve proxy configuration
istioctl proxy-config routes svc/istio-ingressgateway -n istio-system

Step 2: Deploy the Application¶

Prepare the manifest files for our application as follows:

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---         
apiVersion: v1
kind: Namespace
metadata:
  name: test
  labels:
    istio-injection: enabled
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-deploy
  namespace: test
  labels:
    app: test-app
    version: v1
spec: 
  replicas: 1
  selector:
    matchLabels:
      app: test-app
  template:
    metadata:
      labels:
        app: test-app
        version: v1
    spec: 
      containers:
      - name: web
        image: reyanshkharga/nodeapp:v1
        ports:
        - containerPort: 5000
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
        readinessProbe:
          httpGet:
            path: /health
            port: 5000
---
apiVersion: v1
kind: Service
metadata:
  name: test-svc
  namespace: test
spec:   
  selector:
    app: test-app
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 5000

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apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: test-gateway
  namespace: test
spec: 
  selector:
    istio: ingressgateway # use Istio default gateway implementation
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "test.example.com"

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apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: test-virtualservice
  namespace: test
spec: 
  hosts:
  - "test.example.com"
  gateways:
  - test-gateway
  http:
  - match: 
    - uri:   
        prefix: /
    route:
    - destination:
        host: test-svc
        port:
          number: 80

Assuming your folder structure looks like the one below:

|-- manifests
│   |-- app.yml
│   |-- gateway.yml
│   |-- virtualservice.yml

Apply the manifests to deploy the application with istio gateway and virtual service:

kubectl apply -f manifests/

This will create the following kubernetes and Istio resources:

• Kubernetes namespace
• Kubernetes Deployment
• Kubernetes Service
• Istio Gateway
• Istio Virtual Service

Step 3: View the Updated Istio Proxy Configuration¶

View the updated proxy configuration:

# Retrieve proxy configuration
istioctl proxy-config routes svc/istio-ingressgateway -n istio-system

Step 4: Add DNS Record in Route 53¶

Go to AWS Route 53 and add a record that points test.example.com to the load balancer created by Istio Ingress Gateway.

Open any browser and visit test.example.com to verify app.

Here's how the traffic flows across Istio and kubernetes resources:

graph LR
  A(User) --> B("Application Load Balancer
  (associated with istio ingress gateway)");
  B --> C("test-gateway
  (Istio Gateway)");
  C --> D("test-virtualservice
  (Istio Virtual Service)");
  D --> E(test-svc);

In the next section we will update ExternalDNS to make it work with Istio so that DNS records are automatically created in Route 53 based on hosts provided in Istio virtual services.

Clean Up¶

Delete the kubernetes and istio resources we created:

kubectl delete -f manifests/