What is udpbalancer?
--------------------

Udpbalancer acts as a reverse proxy, sitting between clients
and UDP servers. Udpbalancer proxies requests to your servers.

Prerequisites:
--------------

* optional/recommended: DJB's daemontools (http://cr.yp.to/daemontools.html)

Platform:
---------

Udpbalancer is developed and tested on Linux (can be compiled on FreeBSD too).

Install:
--------

Edit config.h then type "make". It should compile cleanly.


Usage:
------

-l <listen address>, -p <port> : obvious

-m <method> : method can be either roundrobin, volumebalance or loadbalance

-x <host1:bogo1,host2:bogo2,..,hostN:bogoN> : hosts definition

-v : verbosity level (you may define it multiple times)


list all of your hosts where host1, host2, ... is the IP address of your hosts
optionally you may set their bogomips values. The higher bogomips value means
that hosts will get more requests then a host with lower bogomips value.

You should always start with hosts having a lower bogomips value (if you choose
roundrobin method it does not matter).

Eg: -x 10.1.1.1:2,10.1.1.2:10 -m volumebalance

In this setup 10.1.1.1 will get every 2 requests of 10 and 10.1.1.2 will have the rest.

If you set the method to loadbalance it will acts just like with volumebalance but in
additionally the response time of the hosts is also considered (see BONUS in config.h).

Security:
---------

Udpbalancer does not have to run as root unless you bind to a privileged port (<1024).
In this case udpbalancer drops root privs after it bound to its listener port.

Flood protection:
-----------------

Udpbalancer works with an iterative model (= one request at a time). If udpbalancer is
flooded and your servers cannot respond quickly you may see as the Recv-Q variable grows
in your netstat output. So you should take some measures to prevent this situation, see
TODO (1).


High availability:
------------------

I recommend you to use DJB's daemontools to supervise udpbalancer.

#!/bin/sh
exec 2>&1
exec /path/to/udpbalancer -lxpmv [switches]