Nginx Ingress Controller x WebSocket

关于在 K8S 中通过 Nginx Ingress Controller 暴露 WebSocket 服务的方法，查到两篇官方文档，说法并不一致。

1. Miscellaneous #Websockets

   Support for websockets is provided by NGINX out of the box. No special configuration required.

   这里说是不需要额外配置即可以支持 WebSocket。

   另外还建议增加 proxy-read-timeout 和 proxy-send-timeout 的值。这两个默认都是 60 秒，建议改成大于 3600 秒。

2. nginxinc / kubernetes-ingress - WebSocket support

   To load balance a WebSocket application with NGINX Ingress controllers, you need to add the nginx.org/websocket-services annotation to your Ingress resource definition. The annotation specifies which services are websocket services. The annotation syntax is as follows:

   nginx.org/websocket-services: "service1[,service2,...]"

   这里是说需要添加 nginx.org/websocket-services 注解，另外还提供了一个完整的示例。

经过实际的测试，不添加 nginx.org/websocket-services 注解时确实是可以访问 WebSocket 服务的，不过不确定是不是因为版本较新的原因（这里使用的 ingressnginx 组件的版本是 1.1.0）。

这里为了以防万一，三个注解都加了，示例如下：

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx-controller-jiajia
    nginx.org/websocket-services: "svc-jiajia-websocket"
    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
  name: ingress-www-liujiajia-me-websocket
  namespace: jiajia-test
spec:
  rules:
  - host: www.liujiajia.me
    http:
      paths:
      - backend:
          serviceName: svc-jiajia-websocket
          servicePort: 80
        path: /ws/
        pathType: ImplementationSpecific
  tls:
  - hosts:
    - www.liujiajia.me
    secretName: tls-www-liujiajia-me