ingress-nginx注解方式使用最小连接数方式实现负载均衡

要使用Ingress-Nginx的注解方式实现最小连接数负载均衡，需要使用nginx.ingress.kubernetes.io/upstream-vhost注解和nginx.ingress.kubernetes.io/upstream-vhost-weight注解。

首先，在Ingress资源的metadata部分添加nginx.ingress.kubernetes.io/upstream-vhost注解，设置为example.com或者你想要指定的主机名。这将为Ingress创建一个独立的上游主机。

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/upstream-vhost: example.com
spec:
  ...

接下来，为每个后端服务添加nginx.ingress.kubernetes.io/upstream-vhost-weight注解，并设置每个服务的权重值。权重值越小，连接数越少。

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/upstream-vhost: example.com
spec:
  rules:
    - host: example.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: backend-service-1
                port:
                  number: 80
              resource:
                annotations:
                  nginx.ingress.kubernetes.io/upstream-vhost-weight: "1" # 设置权重为1

          - path: /api
            pathType: Prefix
            backend:
              service:
                name: backend-service-2
                port:
                  number: 80
              resource:
                annotations:
                  nginx.ingress.kubernetes.io/upstream-vhost-weight: "2" # 设置权重为2

通过以上配置，Ingress-Nginx将按照权重值将流量分发给后端服务。在这个例子中，backend-service-1将接收到更少的连接，因为它的权重值较小