要解决的问题

一个域名，如果只挂一个站点有点浪费，希望可以
aa.hostname.com -> localhost:8000
bb.hostname.com -> localhost:8001

思路

• 在 /etc/hosts 底下加入对hostname.com, aa.hostname.com, bb.hostname.com的解析。
• 二级域名的本质是用proxy_pass来实现的，路径的match导致请求重定向到proxy_pass的地方

方案

这是一个完整的/etc/nginx/nginx.conf，用python -m http.server来做示范了

user www-data;
worker_processes 4;
pid /run/nginx.pid;

events {
    worker_connections 768;
    # multi_accept on;
}

http {

    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    # server_tokens off;

    # server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    ##
    # Gzip Settings
    ##

    gzip on;
    gzip_disable "msie6";

    # gzip_vary on;
    # gzip_proxied any;
    # gzip_comp_level 6;
    # gzip_buffers 16 8k;
    # gzip_http_version 1.1;
    # gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    ##
    # nginx-naxsi config
    ##
    # Uncomment it if you installed nginx-naxsi
    ##

    #include /etc/nginx/naxsi_core.rules;

    ##
    # nginx-passenger config
    ##
    # Uncomment it if you installed nginx-passenger
    ##

    #passenger_root /usr;
    #passenger_ruby /usr/bin/ruby;

    ##
    # Virtual Host Configs
    ##

    server {
        server_name aa.hostname.com;
        listen 80;
        location / {
            proxy_pass  http://127.0.0.1:8000/Documents/;
        }
    }

        server {
        server_name bb.hostname.com;
        listen 80;
        location / {
            proxy_pass  http://127.0.0.1:8001/Documents/;
        }
    }
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

#mail {
#   # See sample authentication script at:
#   # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#   # auth_http localhost/auth.php;
#   # pop3_capabilities "TOP" "USER";
#   # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#   server {
#       listen     localhost:110;
#       protocol   pop3;
#       proxy      on;
#   }
#
#   server {
#       listen     localhost:143;
#       protocol   imap;
#       proxy      on;
#   }
#}

Nginx Road Map

显然只有http协议底下的转发是容易的，需要考虑如果有websocket的情况如何进行转发。
感觉思路应该是大体上一致的。

Ref
Reverse Proxy
Official Admin Guide 值得学的东西太多