Traffic Director

Google Cloud Traffic Director is a fully managed traffic control plane for service mesh. It enables advanced traffic management capabilities for microservices running on GKE, Compute Engine, and other compute environments using the Envoy proxy sidecar.

Key Features:

1. Traffic routing - Advanced routing rules including traffic splitting, URL-based routing, and header-based routing.

2. Load balancing - Service-level load balancing with multiple algorithms (round-robin, weighted, ring hash).

3. Resiliency - Built-in retries, timeouts, circuit breaking, and fault injection for testing.

4. Observability - Automatic telemetry collection for traffic flows between services.

5. Global scale - Control plane manages Envoy proxies across multiple regions centrally.

The below example shows how to configure traffic splitting using Traffic Director.

It gives the following output when checking traffic split,

Traffic Distribution:
  my-service-v1: 90% (stable)
  my-service-v2: 10% (canary)
Active connections: 1,250
Error rate v1: 0.1%
Error rate v2: 0.3%
Decision: Canary healthy, increase to 20%

Traffic Director vs Istio:

Traffic Director - Google managed control plane. No need to manage Istio control plane components. Works with Envoy proxies across GKE and VMs. Best for GCP-native service mesh.

Istio on GKE - Open source service mesh with more customization options. Requires managing control plane (istiod). Better for multi-cloud or on-premises mesh requirements.