Nginx websocket 502 网关错误

Question

我正在尝试使用 nginx 作为 websocket nodejs 服务器的代理，但总是出现 502 错误网关。

我的域配置：

upstream server {
  server 127.0.0.1:8090;
}

server {
 listen 8085;
 server_name server.cz server;
 ssl on;
 #ssl_certificate /etc/ssl/server/server.cz.pem;
 ssl_certificate /etc/ssl/server/server.cz.crt;
 ssl_certificate_key /etc/ssl/server/server.cz.key;

 access_log /var/log/nginx/server.log;
 location / {
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header Host $http_host;
  proxy_set_header X-NginX-Proxy true;

  proxy_pass http://server;
  proxy_redirect off;

  #WEBSOCKET
  proxy_http_version 1.1;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection "upgrade";
 }
}

我正在使用 curl 测试这个：

curl -i -N -vv -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: server.cz" -H "Origin: https://server.cz" -k https://127.0.0.1:8085

这将导致 502 bad gateway full 结果：http://pastebin.com/bL1CYzjt

如果我直接在 nodejs 服务器上尝试此操作，它可以正常工作。

Nginx 日志：

[error] 4083#0: *1 upstream prematurely closed connection while reading response header from upstream, client: 127.0.0.1, server: server.cz, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8090/", host: "server.cz"

服务器日志

"GET / HTTP/1.1" 502 172 "-" "curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3"