proxy_pass

Sets the address of a proxied server. The address can be specified as a domain name or IP address, and a port:

proxy_pass localhost:12345;

or as a UNIX-domain socket path:

proxy_pass unix:/tmp/stream.socket;

If a domain name resolves to several addresses, all of them will be used in a round-robin fashion. In addition, an address can be specified as a server group.

The address can also be specified using variables (1.11.3):

proxy_pass $upstream;

In this case, the server name is searched among the described server groups, and, if not found, is determined using a resolver.