This is a pure-python TCP load balancer. It takes inbound TCP connections and
connects them to one of a number of backend servers.

Features:
- async i/o based, so much less overhead than fork/thread based balancers. Can
  use either twisted or python's standard asyncore library (twisted is
  recommended, and asyncore support will be removed in a future version).
- Multiple scheduling algorithms (random, round robin, leastconns,
  leastconns+roundrobin)
- If a server fails to answer, it's removed from the pool - the client that
  failed to connect gets transparently failed over to a new host.
- XML based configuration file (see a sample)
- separate management thread that periodically re-adds failed hosts if they've
  come back up.
- optional builtin webserver for admin (sample of the running screen)
- webserver has methods suitable for both interactive and automated systems

WWW: http://pythondirector.sourceforge.net/