Perlbal - Reverse-proxy load balancer and webserver
Perlbal is a single-threaded event-based server supporting HTTP load
balancing, web serving, and a mix of the two. Perlbal can act as either a web
server or a reverse proxy.
One of the defining things about Perlbal is that almost everything can be
configured or reconfigured on the fly without needing to restart the software.
A basic configuration file containing a management port enables you to easily
perform operations on a running instance of Perlbal.
Perlbal can also be extended by means of per-service (and global) plugins that
can override many parts of request handling and behavior.