How does Istio Traffic Management work?

Question

Accepted Answer

**Istio Traffic Management** — managing traffic routing between microservices.

**Key components:**

**1. VirtualService — traffic routing:**
```yaml
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: myapp
spec:
  hosts:
    - myapp
  http:
    - match:
        - headers:
            x-canary:
              exact: "true"
      route:
        - destination:
            host: myapp
            subset: v2
    - route:
        - destination:
            host: myapp
            subset: v1
          weight: 90
        - destination:
            host: myapp
            subset: v2
          weight: 10
      retries:
        attempts: 3
        perTryTimeout: 2s
      timeout: 10s
```

**2. DestinationRule — policies and subsets:**
```yaml
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: myapp
spec:
  host: myapp
  trafficPolicy:
    connectionPool:
      tcp:
        maxConnections: 100
    outlierDetection:
      consecutive5xxErrors: 5
      interval: 30s
      baseEjectionTime: 30s
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2
```

**3. Gateway — external entry:**
```yaml
apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: my-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
    - port:
        number: 443
        name: https
        protocol: HTTPS
      tls:
        mode: SIMPLE
      hosts:
        - myapp.com
```

**Capabilities:** Canary deployments, A/B testing, circuit breaking, retries, timeouts, fault injection.

DevOps: How does Istio Traffic Management work?