.Dd 2005-05-25
.Dt fair 7
.Os "Debian GNU/Linux"
.\" $Id: fair.7 96 2005-05-31 17:02:37Z wsl $
.\" $URL: https://svn.fair.uvt.nl/branches/0.5/doc/fair.7 $
.Sh NAME
.Nm fair
.Nd simple TCP load balancing service
.Sh DESCRIPTION
.Nm
is a load balancer for TCP connections.
It can be used to distribute incoming connections for SMTP, HTTP or any
other TCP service to multiple hosts, distributing the load as evenly as
possible.
.Pp
.Nm
consists of two daemons.
The
.Nm carrousel
is the front-end;
it keeps track of back-end hosts and their status,
and forwards incoming connections to the back-ends in such a way that the load is distributed fairly.
The
.Nm transponder
runs on the back-end hosts,
it registers with the carrousel and sends it status information.
The TCP connections forwarded by the
.Nm carrousel
are not sent to the
.Nm transponder
daemons but are sent directly to the desired service running on the back-end
host. Both daemons share a single configuration file.
.Sh EXAMPLES
The following example shows how to set up
.Nm
to service HTTP connections and to distribute them over back-ends in the
192.168.1.0/24 subnet.
.Pp
The configuration file
.Pa /etc/fair.conf
contains the following:
.Bd -literal -offset indent
WorkerService = http
BalancerService = http
AllowUDP = ^192\.168\.1\.[0-9]+$
.Ed
.Pp
On
.Pa www.example.com ,
the front-end server receiving the incoming HTTP connections, just run:
.Bd -literal -offset indent
carrousel
.Ed
.Pp
On each of the back-ends run:
.Bd -literal -offset indent
transponder www.example.com
.Ed
.Sh SEE ALSO
.Xr carrousel 8 ,
.Xr transponder 8 ,
.Xr fair.conf 5