upstream piston { server 127.0.0.1:2001; server 127.0.0.1:2002; server 127.0.0.1:2003; server 127.0.0.1:2004; server 127.0.0.1:2005; server 127.0.0.1:2006; server 127.0.0.1:2007; server 127.0.0.1:2008; server 127.0.0.1:2009; server 127.0.0.1:2010; } server { listen 80; location / { proxy_pass http://piston; } }