反向代理nginx docker容器和ELB

Question

我正在尝试在同一台机器上设置多个监听不同端口的应用程序。所有应用程序都基于docker容器。我希望每个应用程序都有不同的子域名。我已将多个子域配置为指向同一个elb。

我有以下设置：

ELB 使用 SSL 转发到特定的 CNAME，最终将流量转发到 EC2 实例的端口 80。在 EC2 实例上，我有一个从这里获取的 nginx 容器正在运行。我有一个 docker 容器，它公开端口 3001 并设置了一个配置了子域的虚拟主机，如链接中所述。

我正在尝试将每个 http 请求重定向到子域 sub.example.com 到实例中的容器。

我不断从 nginx 收到 502 和以下错误日志：

2018/07/14 08:45:58 [error] 137#137: *20 connect() failed (111: Connection refused)
while connecting to upstream, client: 111.111.111.11, server: sub.example.com,
request: "GET / HTTP/1.1", upstream: "http://172.17.0.2:3001/", host: "sub.example.com"

其中 172.17.0.2 是我想要访问的容器。

这是 nginx 从容器中获取的默认配置：

# If we receive X-Forwarded-Proto, pass it through; otherwise, pass along the
# scheme used to connect to this server
map $http_x_forwarded_proto $proxy_x_forwarded_proto {
  default $http_x_forwarded_proto;
  ''      $scheme;
}
# If we receive X-Forwarded-Port, pass it through; otherwise, pass along the
# server port the client connected to
map $http_x_forwarded_port $proxy_x_forwarded_port {
  default $http_x_forwarded_port;
  ''      $server_port;
}
# If we receive Upgrade, set Connection to "upgrade"; otherwise, delete any
# Connection header that may have been passed to this server
map $http_upgrade $proxy_connection {
  default upgrade;
  '' close;
}
# Apply fix for very long server names
server_names_hash_bucket_size 128;
# Default dhparam
ssl_dhparam /etc/nginx/dhparam/dhparam.pem;
# Set appropriate X-Forwarded-Ssl header
map $scheme $proxy_x_forwarded_ssl {
  default off;
  https on;
}
gzip_types text/plain text/css application/javascript application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;
log_format vhost '$host $remote_addr - $remote_user [$time_local] '
                 '"$request" $status $body_bytes_sent '
                 '"$http_referer" "$http_user_agent"';
access_log off;
resolver 172.31.0.2;
# HTTP 1.1 support
proxy_http_version 1.1;
proxy_buffering off;
proxy_set_header Host $http_host;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $proxy_connection;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
proxy_set_header X-Forwarded-Ssl $proxy_x_forwarded_ssl;
proxy_set_header X-Forwarded-Port $proxy_x_forwarded_port;
# Mitigate httpoxy attack (see README for details)
proxy_set_header Proxy "";
server {
    server_name _; # This is just an invalid value which will never trigger on a real hostname.
    listen 80;
    access_log /var/log/nginx/access.log vhost;
    return 503;
}
# ssrv.talking-ads.com
upstream ssrv.talking-ads.com {
                ## Can be connected with "bridge" network
            # display
            server 172.17.0.2:3001;
}
server {
    server_name ssrv.talking-ads.com;
    listen 80 ;
access_log /var/log/nginx/access.log vhost;
    location / {
        proxy_pass http://ssrv.talking-ads.com;
    }
}