5.1.5　网关资源

网关资源用来配置Envoy的端口，前面的示例中已经使用该服务公开了三个端口，因此需要在Envoy中处理这些端口。此外，可以通过声明一个或多个Gateways来支持多端口能力。下面的示例中使用单个Gateway，但可以分为两个或三个分别定义：

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: default-gateway
  namespace: istio-system
spec:
  selector:
    istio: ingressgateway
  servers:

  - hosts:
    - '*'
    port:
      name: http
      number: 80
      protocol: HTTP

  - hosts:
    - '*'
    port:
      name: https
      number: 443
      protocol: HTTPS
    tls:
      mode: SIMPLE
      privateKey: /etc/istio/ingressgateway-certs/tls.key
      serverCertificate: /etc/istio/ingressgateway-certs/tls.crt

  - hosts: # For TCP routing this fields seems to be ignored, but it is matched
    - '*'  # with the VirtualService, I use * since it will match anything.
    port:
      name: mysql
      number: 3306
      protocol: TCP