Ambassador中，启用不同的Load balancing算法

默认就是轮循，如果要其它hash或是最少请求，那就需要作更多的设置了。

https://www.getambassador.io/reference/core/load-balancer/#source-ip

默认是用的Kubernetes services这个resolver，如果要使用高级的LB功能，就需要使用

the Kubernetes Endpoint Resolver or Consul Resolver。

针对mapping的配置如下：

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deploy
spec:
  replicas: 3
  selector:
    matchLabels:
      name: nginx
  template:
    metadata:
      labels:
        name: nginx
    spec:
      containers:
        - name: nginx
          image: harbor.xxx.cn/base/middleware/nginx:1.13-alpine
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  annotations:
    getambassador.io/config: |
      ---
      apiVersion: ambassador/v1
      kind: KubernetesEndpointResolver
      name: my_endpoint
      ---
      apiVersion: ambassador/v1
      kind: Mapping
      name: ngnix_mapping
      prefix: /
      service: nginx-service:80
      resolver: my_endpoint
      load_balancer:
        policy: round_robin
        # source_ip: true

spec:
  ports:
    - name: nginx
      port: 80
      targetPort: 80
      protocol: TCP
  selector:
    name: nginx