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

Provided by: haproxy_2.4.24-0ubuntu0.22.04.1_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)