ambassador kubernetes native api gateway
github 上的介绍：
Ambassador is an open source Kubernetes-native API Gateway built on Envoy, designed for microservices. Key features include:
- Self-service configuration, via Kubernetes annotations
- First class gRPC and HTTP/2 support
- Support for CORS, timeouts, weighted round robin (canary), and more
- Istio integration
- Authentication
- Robust TLS support, including TLS client-certificate authentication
架构说明：
https://blog.getambassador.io/building-ambassador-an-open-source-api-gateway-on-kubernetes-and-envoy-ed01ed520844
