Ubuntu Manpage: HAProxy - fast and reliable http reverse proxy and load balancer

Provided by: haproxy_2.4.24-0ubuntu0.22.04.3_amd64

NAME

       HAProxy - fast and reliable http reverse proxy and load balancer

SYNOPSIS

       haproxy  -f  <configuration file|dir> [-L <name>] [-n maxconn] [-N maxconn] [-C <dir>] [-v|-vv] [-d] [-D]
       [-W] [-Ws] [-q] [-V] [-c] [-p <pidfile>] [-dk] [-ds] [-de]  [-dp]  [-db]  [-dM[<byte>]]  [-m <megs>]  [-x
       <unix_socket>] [{-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|dir>
Specify configuration file or directory path. If the argument is a directory the files (and only
files) it contains are added in lexical order (using LC_COLLATE=C) ; only non hidden files with
".cfg" extension are added.

-L <name>
Set the local instance's peer name. Peers are defined in the peers configuration section and used
for syncing stick tables between different instances. If this option is not specified, the local
hostname is used as peer name. This name is exported in the $HAPROXY_LOCALPEER environment
variable and can be used in the configuration file.

-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.

-C <dir>
Change directory to <dir> before loading any files.

-v Display HAProxy's version.

-vv Display HAProxy's version and all build options.

-d Start in foreground 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.

-W Start in master-worker mode. Could be used either with foreground or daemon mode.

-Ws Start in master-worker mode with systemd notify support. It tells systemd when the process is
ready. This mode forces foreground.

-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 or ask the
process to write down its master's pid to this file in master-worker mode.

-dk Disable use of kqueue(2). kqueue(2) is available only on BSD systems.

-dv Disable use of event ports. Event ports are available only on SunOS systems derived from Solaris
10 and later (including illumos systems).

-ds Disable use of speculative epoll(7). epoll(7) is available only on Linux 2.6 and some custom Linux
2.4 systems.

-de Disable use of epoll(7). epoll(7) is available only on Linux 2.6 and some custom Linux 2.4
systems.

-dp Disables use of poll(2). select(2) might be used instead.

-dS Disables use of splice(2), which is broken on older kernels.

-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.

-dM[<byte>]
Initializes all allocated memory areas with the given <byte>. This makes it easier to detect bugs
resulting from uninitialized memory accesses, at the expense of touching all allocated memory
once. If <byte> is not specified, it defaults to 0x50 (ASCII 'P').

-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 terminate immediately, closing all active sessions. This option must be specified
last, followed by any number of PIDs. Technically speaking, SIGTTOU and SIGTERM are sent.

-x <unix_socket>
Attempt to connect to the unix socket, and retrieve all the listening sockets from the old
process. Those sockets will then be used if possible instead of binding new ones.

-S <bind>[,<bind options>...]
In master-worker mode, create a master CLI. This CLI will enable access to the CLI of every
worker. Useful for debugging, it's a convenient way of accessing a leaving process.

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.

       - SIGUSR2
              In master-worker mode, reloads the configuration and sends a soft-stop signal to old processes.

       - 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 on stderr. Mostly used for debugging purposes.

       - SIGPIPE
              This signal is intercepted and ignored on systems without MSG_NOSIGNAL.

AUTHOR

       HAProxy was written by Willy Tarreau. This man page was written by Arnaud Cornet and Willy Tarreau.

                                                 17 August 2007                                       HAPROXY(1)