This is the command haproxy that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
HAProxy - fast and reliable http reverse proxy and load balancer
SYNOPSIS
haproxy -f <configuration file> [-L <name>] [-n maxconn] [-N maxconn] [-C <dir>] [-v|-vv]
[-d] [-D] [-q] [-V] [-c] [-p <pidfile>] [-dk] [-ds] [-de] [-dp] [-db] [-dM[<byte>]]
[-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.
-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.
-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.
-Ds Start in systemd daemon mode, keeping a process in 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.
-dk Disable use of kqueue(2). kqueue(2) is available only on BSD 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 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 on stderr. Mostly used for debugging purposes.
- SIGPIPE
This signal is intercepted and ignored on systems without MSG_NOSIGNAL.
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