NAME
HAProxy - fast and reliable http reverse proxy and load balancer
SYNOPSIS
haproxy -f <configuration file> [-n maxconn] [-N maxconn] [-d] [-D]
[-q] [-V] [-c] [-p <pidfile>] [-s] [-l] [-dk] [-ds] [-de] [-dp] [-db]
[-m <megs>] [{-sf|-st} pidlist...]
DESCRIPTION
HAProxy is a TCP/HTTP reverse proxy which is particularly suited for
high availability environments. Indeed, it can:
- route HTTP requests depending on statically assigned cookies ;
- spread the load among several servers while assuring server
persistence through the use of HTTP cookies ;
- switch to backup servers in the event a main one fails ;
- accept connections to special ports dedicated to service
monitoring ;
- stop accepting connections without breaking existing ones ;
- add/modify/delete HTTP headers both ways ;
- block requests matching a particular pattern ;
- hold clients to the right application server depending on
application cookies
- report detailed status as HTML pages to authenticated users from an
URI intercepted from the application.
It needs very little resource. Its event-driven architecture allows it
to easily handle thousands of simultaneous connections on hundreds of
instances without risking the system’s stability.
OPTIONS
-f <configuration file>
Specify configuration file path.
-n <maxconn>
Set the high limit for the total number of simultaneous
connections.
-N <maxconn>
Set the high limit for the per-listener number of simultaneous
connections.
-d Start in foregreound with debugging mode enabled. When the
proxy runs in this mode, it dumps every connections,
disconnections, timestamps, and HTTP headers to stdout. This
should NEVER be used in an init script since it will prevent the
system from starting up.
-D Start in daemon mode.
-q Disable messages on output.
-V Displays messages on output even when -q or ’quiet’ are
specified. Some information about pollers and config file are
displayed during startup.
-c Only checks config file and exits with code 0 if no error was
found, or exits with code 1 if a syntax error was found.
-p <pidfile>
Ask the process to write down each of its children’s pids to
this file in daemon mode.
-s Show statistics (only if compiled in). Statistics are only
available if compiled in with the ’STATTIME’ option. It’s only
used during code optimization phases, and will soon disappear.
-l Show even more statistics (implies ’-s’).
-dk Disable use of kqueue(). kqueue() is available only on BSD
systems.
-ds Disable use of speculative epoll(). epoll() is available only on
Linux 2.6 and some custom Linux 2.4 systems.
-de Disable use of epoll(). epoll() is available only on Linux 2.6
and some custom Linux 2.4 systems.
-dp Disables use of poll(). select() might be used instead.
-db Disables background mode (stays in foreground, useful for
debugging). For debugging, the ’-db’ option is very useful as
it temporarily disables daemon mode and multi-process mode. The
service can then be stopped by simply pressing Ctrl-C, without
having to edit the config nor run full debug.
-m <megs>
Enforce a memory usage limit to a maximum of <megs> megabytes.
-sf <pidlist>
Send FINISH signal to the pids in pidlist after startup. The
processes which receive this signal will wait for all sessions
to finish before exiting. This option must be specified last,
followed by any number of PIDs. Technically speaking, SIGTTOU
and SIGUSR1 are sent.
-st <pidlist>
Send TERMINATE signal to the pids in pidlist after startup. The
processes which receive this signal will wait immediately
terminate, closing all active sessions. This option must be
specified last, followed by any number of PIDs. Technically
speaking, SIGTTOU and SIGTERM are sent.
LOGGING
Since HAProxy can run inside a chroot, it cannot reliably access
/dev/log. For this reason, it uses the UDP protocol to send its logs
to the server, even if it is the local server. People who experience
trouble receiving logs should ensure that their syslog daemon listens
to the UDP socket. Several Linux distributions which ship with syslogd
from the sysklogd package have UDP disabled by default. The -r option
must be passed to the daemon in order to enable UDP.
SIGNALS
Some signals have a special meaning for the haproxy daemon. Generally,
they are used between daemons and need not be used by the
administrator.
- SIGUSR1
Tells the daemon to stop all proxies and exit once all sessions
are closed. It is often referred to as the "soft-stop" signal.
- SIGTTOU
Tells the daemon to stop listening to all sockets. Used
internally by -sf and -st.
- SIGTTIN
Tells the daemon to restart listening to all sockets after a
SIGTTOU. Used internally when there was a problem during hot
reconfiguration.
- SIGINT and SIGTERM
Both signals can be used to quickly stop the daemon.
- SIGHUP
Dumps the status of all proxies and servers into the logs.
Mostly used for trouble-shooting purposes.
- SIGQUIT
Dumps information about memory pools into the logs. Mostly used
for debugging purposes.
- SIGPIPE
This signal is intercepted and ignored on systems without
MSG_NOSIGNAL.
SEE ALSO
A much better documentation can be found in haproxy-en.txt. On debian
systems, you can find this file in /usr/share/doc/haproxy/haproxy-
en.txt.gz.
AUTHOR
HAProxy was written by Willy Tarreau. This man page was written by
Arnaud Cornet and Willy Tarreau.
17 August 2007