Istio-ServiceEntry应用

一.ServiceEntry详解

ServiceEntry允许将其他条目添加到 Istio 的内部服务注册表中，以便网格中自动发现的服务可以访问/路由到这些手动指定的服务。服务条目描述了服务的属性（DNS 名称、VIP、端口、协议、端点）

1.配置一个内部服务访问外部api的入口

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-https
spec:
  hosts:
  - api.dropboxapi.com
  - www.googleapis.com
  - api.facebook.com
  location: MESH_EXTERNAL
  ports:
  - number: 443
    name: https
    protocol: TLS
  resolution: DNS

2.配置一个集群外的MongoDB添加到Istio集群中

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-mongocluster
spec:
  hosts:
  - mymongodb.somedomain # not used
  addresses:
  - 192.192.192.192/24 # VIPs
  ports:
  - number: 27018
    name: mongodb
    protocol: MONGO
  location: MESH_INTERNAL
  resolution: STATIC
  endpoints:
  - address: 2.2.2.2
  - address: 3.3.3.3

和相关的 DestinationRule

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: mtls-mongocluster
spec:
  host: mymongodb.somedomain
  trafficPolicy:
    tls:
      mode: MUTUAL
      clientCertificate: /etc/certs/myclientcert.pem
      privateKey: /etc/certs/client_private_key.pem
      caCertificates: /etc/certs/rootcacerts.pem

3.配置出口Egress

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-httpbin
  namespace : egress
spec:
  hosts:
  - httpbin.com
  exportTo:
  - "."
  location: MESH_EXTERNAL
  ports:
  - number: 80
    name: http
    protocol: HTTP
  resolution: DNS

定义一个Gateway来处理出口流量

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
 name: istio-egressgateway
 namespace: istio-system
spec:
 selector:
   istio: egressgateway
 servers:
 - port:
     number: 80
     name: http
     protocol: HTTP
   hosts:
   - "*"