.\"	$OpenBSD: hoststated.8,v 1.10 2007/09/28 18:08:00 pyr Exp $
.\"
.\" Copyright (c) 2006 Pierre-Yves Ritschard <pyr@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: September 28 2007 $
.Dt HOSTSTATED 8
.Os
.Sh NAME
.Nm hoststated
.Nd Host Status daemon
.Sh SYNOPSIS
.Nm
.Op Fl dnv
.Oo Xo
.Fl D Ar macro Ns = Ns Ar value Oc
.Xc
.Op Fl f Ar file
.Sh DESCRIPTION
.Nm
is a host status daemon for server load-balancing.
It monitors groups of hosts for availability,
which is determined by checking for a specific service
common to a host group.
When availability is confirmed, Layer 3 and/or Layer 7
load-balancing services are set up by
.Nm .
.Pp
Layer 3 load-balancing happens at the packet level; to configure
it,
.Nm
communicates with
.Xr pf 4 .
To allow
.Nm
to properly set up
.Xr pf 4
rules, the following line is required in the NAT section of
.Xr pf.conf 5 :
.Bd -literal -offset indent
rdr-anchor "hoststated/*"
.Ed
.Pp
Layer 7 load-balancing happens at the application level and is
handled by
.Nm
itself.
.Pp
.Nm
works in terms of the following
.Em entities :
relays, protocols, services, and tables.
A
.Em relay
represents a Layer 7 load-balancing instance.
Each instance translates to a listening TCP or UDP port.
A
.Em protocol
defines which actions, if any, must be taken on the
packet payload as data crosses a relay.
A
.Em service
represents a Layer 3 load-balancing instance.
Each instance translates to a
.Xr pf 4
rdr rule being added.
A
.Em table
represents a group of hosts which can be checked for
availability using the same method.
Each table contains at least one host.
If a table is used in a Layer 3 load-balancing instance, it
will be mapped to a
.Xr pf 4
table containing only hosts which are up.
.Pp
All these entities can be configured in
.Xr hoststated.conf 5
and
.Xr hoststatectl 8
can be used to alter or report the status of each entity.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl D Ar macro Ns = Ns Ar value
Define
.Ar macro
to be set to
.Ar value
on the command line.
Overrides the definition of
.Ar macro
in the configuration file.
.It Fl d
Do not daemonize.
If this option is specified,
.Nm
will run in the foreground and log to
.Em stderr .
.It Fl f Ar file
Specify an alternative configuration file.
The default is
.Pa /etc/hoststated.conf .
.It Fl n
Configtest mode.
Only check the configuration file for validity.
.It Fl v
Produce more verbose output.
.El
.Sh FILES
.Bl -tag -width "/var/run/hoststated.sockXX" -compact
.It /etc/hoststated.conf
Default
.Nm
configuration file.
.It /var/run/hoststated.sock
Unix-domain socket used for communication with
.Xr hoststatectl 8 .
.El
.Sh SEE ALSO
.Xr hoststated.conf 5 ,
.Xr hoststatectl 8
.Sh HISTORY
The
.Nm
program first appeared in
.Ox 4.1 .
.Sh AUTHORS
.An -nosplit
The
.Nm
program was written by
.An Pierre-Yves Ritschard Aq pyr@openbsd.org
and
.An Reyk Floeter Aq reyk@openbsd.org .