stopping.html.en revision c20b8f35a22c3a19f0f6390f7aba054ca95dd92e
45632c3574ce843b9e85b9f73efe75b7b809f789slive<?xml version="1.0" encoding="ISO-8859-1"?>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd This file is generated from xml source: DO NOT EDIT
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd -->
3f08db06526d6901aa08c110b5bc7dde6bc39905nd<title>Stopping and Restarting - Apache HTTP Server</title>
6df89e6e4adeb986b41b7ec6b7593a887e031ce7nd<link href="/style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim<link href="/style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim<link href="/style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
d29d9ab4614ff992b0e8de6e2b88d52b6f1f153erbowen<link href="/images/favicon.ico" rel="shortcut icon" /></head>
d29d9ab4614ff992b0e8de6e2b88d52b6f1f153erbowen<body id="manual-page"><div id="page-header">
d29d9ab4614ff992b0e8de6e2b88d52b6f1f153erbowen<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="/faq/">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p>
d29d9ab4614ff992b0e8de6e2b88d52b6f1f153erbowen<p class="apache">Apache HTTP Server Version 2.3</p>
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim<img alt="" src="/images/feather.gif" /></div>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div class="up"><a href="./"><img title="&lt;-" alt="&lt;-" src="/images/left.gif" /></a></div>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div id="path">
af33a4994ae2ff15bc67d19ff1a7feb906745bf8rbowen<a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="./">Version 2.3</a></div><div id="page-content"><div id="preamble"><h1>Stopping and Restarting</h1>
3f08db06526d6901aa08c110b5bc7dde6bc39905nd<div class="toplang">
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim<p><span>Available Languages: </span><a href="/de/stopping.html" hreflang="de" rel="alternate" title="Deutsch">&nbsp;de&nbsp;</a> |
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim<a href="/en/stopping.html" title="English">&nbsp;en&nbsp;</a> |
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<a href="/es/stopping.html" hreflang="es" rel="alternate" title="Espa�ol">&nbsp;es&nbsp;</a> |
4b5981e276e93df97c34e4da05ca5cf8bbd937dand<a href="/fr/stopping.html" hreflang="fr" rel="alternate" title="Fran�ais">&nbsp;fr&nbsp;</a> |
3f08db06526d6901aa08c110b5bc7dde6bc39905nd<a href="/ja/stopping.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
6df89e6e4adeb986b41b7ec6b7593a887e031ce7nd<a href="/ko/stopping.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd</div>
ed1d958582984a7c54a6ca859e15939a414fa733nd
ed1d958582984a7c54a6ca859e15939a414fa733nd <p>This document covers stopping and restarting Apache on
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim Unix-like systems. Windows NT, 2000 and XP users should see
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim <a href="platform/windows.html#winsvc">Running Apache as a
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim Service</a> and Windows 9x and ME users should see <a href="platform/windows.html#wincons">Running Apache as a
7f5b59ccc63c0c0e3e678a168f09ee6a2f51f9d0nd Console Application</a> for information on how to control
7f5b59ccc63c0c0e3e678a168f09ee6a2f51f9d0nd Apache on those platforms.</p>
63f06dce77bb2d9b1c5aa5deeb47a1069987fd1end</div>
d474d8ef01ec5c2a09341cd148851ed383c3287crbowen<div id="quickview"><ul id="toc"><li><img alt="" src="/images/down.gif" /> <a href="#introduction">Introduction</a></li>
d474d8ef01ec5c2a09341cd148851ed383c3287crbowen<li><img alt="" src="/images/down.gif" /> <a href="#term">Stop Now</a></li>
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd<li><img alt="" src="/images/down.gif" /> <a href="#graceful">Graceful Restart</a></li>
3f08db06526d6901aa08c110b5bc7dde6bc39905nd<li><img alt="" src="/images/down.gif" /> <a href="#hup">Restart Now</a></li>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<li><img alt="" src="/images/down.gif" /> <a href="#gracefulstop">Graceful Stop</a></li>
a29610af88e278144045bfa1bc63b4a1a4b5ff14trawick</ul><h3>See also</h3><ul class="seealso"><li><code class="program"><a href="/programs/httpd.html">httpd</a></code></li><li><code class="program"><a href="/programs/apachectl.html">apachectl</a></code></li><li><a href="invoking.html">Starting</a></li></ul></div>
52fff662005b1866a3ff09bb6c902800c5cc6dedjerenkrantz<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
35b1112eadc3479a2d81ea1b836aa87f21505ee9jerenkrantz<div class="section">
52fff662005b1866a3ff09bb6c902800c5cc6dedjerenkrantz<h2><a name="introduction" id="introduction">Introduction</a></h2>
a12dd6260a66f51e25119982390def72e2db4be5nd
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <p>In order to stop or restart Apache, you must send a signal to
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd the running <code class="program"><a href="/programs/httpd.html">httpd</a></code> processes. There are two ways to
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd send the signals. First, you can use the unix <code>kill</code>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd command to directly send signals to the processes. You will
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd notice many <code class="program"><a href="/programs/httpd.html">httpd</a></code> executables running on your system,
af33a4994ae2ff15bc67d19ff1a7feb906745bf8rbowen but you should not send signals to any of them except the parent,
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd whose pid is in the <code class="directive"><a href="/mod/mpm_common.html#pidfile">PidFile</a></code>. That is to say you
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd shouldn't ever need to send signals to any process except the
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd parent. There are four signals that you can send the parent:
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <code><a href="#term">TERM</a></code>,
63581ee088272ef76aa8d053609dc1705c222deesf <code><a href="#graceful">USR1</a></code>,
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <code><a href="#hup">HUP</a></code>, and
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <code><a href="#gracefulstop">WINCH</a></code>, which
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd will be described in a moment.</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
562b6e25d7f0ca73dca724b09b555a91399448d5rbowen <p>To send a signal to the parent you should issue a command
562b6e25d7f0ca73dca724b09b555a91399448d5rbowen such as:</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div class="example"><p><code>kill -TERM `cat /usr/local/apache2/logs/httpd.pid`</code></p></div>
4af55bbfdbff2cae0cd3195876c93ea991523d1fcolm
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <p>The second method of signaling the <code class="program"><a href="/programs/httpd.html">httpd</a></code> processes
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd is to use the <code>-k</code> command line options: <code>stop</code>,
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <code>restart</code>, <code>graceful</code> and <code>graceful-stop</code>,
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd as described below. These are arguments to the <code class="program"><a href="/programs/httpd.html">httpd</a></code> binary, but we recommend that
64f23d7fddbd8bacb8c18434baedb5f1f86b432aminfrin you send them using the <code class="program"><a href="/programs/apachectl.html">apachectl</a></code> control script, which
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd will pass them through to <code class="program"><a href="/programs/httpd.html">httpd</a></code>.</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <p>After you have signaled <code class="program"><a href="/programs/httpd.html">httpd</a></code>, you can read about
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd its progress by issuing:</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div class="example"><p><code>tail -f /usr/local/apache2/logs/error_log</code></p></div>
38819b9bf8b10d6db4842fb5a4ede7828b409819rbowen
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <p>Modify those examples to match your <code class="directive"><a href="/mod/core.html#serverroot">ServerRoot</a></code> and <code class="directive"><a href="/mod/mpm_common.html#pidfile">PidFile</a></code> settings.</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div class="section">
1844bb5f7939bd31f51dffaf8d8cf1c00657a681rbowen<h2><a name="term" id="term">Stop Now</a></h2>
1844bb5f7939bd31f51dffaf8d8cf1c00657a681rbowen
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<dl><dt>Signal: TERM</dt>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<dd><code>apachectl -k stop</code></dd>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd</dl>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd <p>Sending the <code>TERM</code> or <code>stop</code> signal to
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd the parent causes it to immediately attempt to kill off all of its
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd children. It may take it several seconds to complete killing off
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd its children. Then the parent itself exits. Any requests in
664e667e221a15fa5f456e73948c67710f43f1b4minfrin progress are terminated, and no further requests are served.</p>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<div class="section">
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<h2><a name="graceful" id="graceful">Graceful Restart</a></h2>
c5ac4f57bfd156a62495b9c6a049f05bbcb69acarbowen
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<dl><dt>Signal: USR1</dt>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd<dd><code>apachectl -k graceful</code></dd>
0f6a0052bbfc841b1067c1ce0ca37880121d4713rbowen</dl>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd
e930328445e961ade1bd37ed7ca01c293b586400noodl <p>The <code>USR1</code> or <code>graceful</code> signal causes
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd the parent process to <em>advise</em> the children to exit after
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd their current request (or to exit immediately if they're not
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd serving anything). The parent re-reads its configuration files and
ed1d958582984a7c54a6ca859e15939a414fa733nd re-opens its log files. As each child dies off the parent replaces
ed1d958582984a7c54a6ca859e15939a414fa733nd it with a child from the new <em>generation</em> of the
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim configuration, which begins serving new requests immediately.</p>
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim
7add1372edb1ee95a2c4d1314df4c7567bda7c62jim <p>This code is designed to always respect the process control
7f5b59ccc63c0c0e3e678a168f09ee6a2f51f9d0nd directive of the MPMs, so the number of processes and threads
7f5b59ccc63c0c0e3e678a168f09ee6a2f51f9d0nd available to serve clients will be maintained at the appropriate
63f06dce77bb2d9b1c5aa5deeb47a1069987fd1end values throughout the restart process. Furthermore, it respects
d474d8ef01ec5c2a09341cd148851ed383c3287crbowen <code class="directive"><a href="/mod/mpm_common.html#startservers">StartServers</a></code> in the
d474d8ef01ec5c2a09341cd148851ed383c3287crbowen following manner: if after one second at least <code class="directive"><a href="/mod/mpm_common.html#startservers">StartServers</a></code> new children have not
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd been created, then create enough to pick up the slack. Hence the
1a1356f375e36db7bee379ea0684ab389579f798rbowen code tries to maintain both the number of children appropriate for
af33a4994ae2ff15bc67d19ff1a7feb906745bf8rbowen the current load on the server, and respect your wishes with the
0d0ba3a410038e179b695446bb149cce6264e0abnd <code class="directive"><a href="/mod/mpm_common.html#startservers">StartServers</a></code>
7fec19672a491661b2fe4b29f685bc7f4efa64d4nd parameter.</p>
7fec19672a491661b2fe4b29f685bc7f4efa64d4nd
7fec19672a491661b2fe4b29f685bc7f4efa64d4nd <p>Users of <code class="module"><a href="/mod/mod_status.html">mod_status</a></code>
29fb68cf24dbdb4985cbb4734cb6074ea4bbab26nd will notice that the server statistics are <strong>not</strong>
set to zero when a <code>USR1</code> is sent. The code was
written to both minimize the time in which the server is unable
to serve new requests (they will be queued up by the operating
system, so they're not lost in any event) and to respect your
tuning parameters. In order to do this it has to keep the
<em>scoreboard</em> used to keep track of all children across
generations.</p>
<p>The status module will also use a <code>G</code> to indicate
those children which are still serving requests started before
the graceful restart was given.</p>
<p>At present there is no way for a log rotation script using
<code>USR1</code> to know for certain that all children writing
the pre-restart log have finished. We suggest that you use a
suitable delay after sending the <code>USR1</code> signal
before you do anything with the old log. For example if most of
your hits take less than 10 minutes to complete for users on
low bandwidth links then you could wait 15 minutes before doing
anything with the old log.</p>
<div class="note">
<p>When you issue a restart, a syntax check is first run, to
ensure that there are no errors in the configuration files.
If your configuration file has errors in it, you will get an
error message about that syntax error, and the server will refuse to
restart. This avoids the situation where the server halts and then
cannot restart, leaving you with a non-functioning server.</p>
<p>This still will not
guarantee that the server will restart correctly. To check the
semantics of the configuration files as well as the syntax, you
can try starting <code class="program"><a href="/programs/httpd.html">httpd</a></code> as a non-root user. If there
are no errors it will attempt to open its sockets and logs and fail
because it's not root (or because the currently running
<code class="program"><a href="/programs/httpd.html">httpd</a></code> already has those ports bound). If it fails
for any other reason then it's probably a config file error and the error
should be fixed before issuing the graceful restart.</p></div>
</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
<div class="section">
<h2><a name="hup" id="hup">Restart Now</a></h2>
<dl><dt>Signal: HUP</dt>
<dd><code>apachectl -k restart</code></dd>
</dl>
<p>Sending the <code>HUP</code> or <code>restart</code> signal to
the parent causes it to kill off its children like in
<code>TERM</code>, but the parent doesn't exit. It re-reads its
configuration files, and re-opens any log files. Then it spawns a
new set of children and continues serving hits.</p>
<p>Users of <code class="module"><a href="/mod/mod_status.html">mod_status</a></code>
will notice that the server statistics are set to zero when a
<code>HUP</code> is sent.</p>
<div class="note">As with a graceful restart, a syntax check is run before the
restart is attempted. If your configuration file has errors in it, the
restart will not be attempted, and you will receive notification of the
syntax error(s).</div>
</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
<div class="section">
<h2><a name="gracefulstop" id="gracefulstop">Graceful Stop</a></h2>
<dl><dt>Signal: WINCH</dt>
<dd><code>apachectl -k graceful-stop</code></dd>
</dl>
<p>The <code>WINCH</code> or <code>graceful-stop</code> signal causes
the parent process to <em>advise</em> the children to exit after
their current request (or to exit immediately if they're not
serving anything). The parent will then remove its <code class="directive"><a href="/mod/mpm_common.html#pidfile">PidFile</a></code> and cease listening on
all ports. The parent will continue to run, and monitor children
which are handling requests. Once all children have finalised
and exited or the timeout specified by the <code class="directive"><a href="/mod/mpm_common.html#gracefulshutdowntimeout">GracefulShutdownTimeout</a></code> has been
reached, the parent will also exit. If the timeout is reached,
any remaining children will be sent the <code>TERM</code> signal
to force them to exit.</p>
<p>A <code>TERM</code> signal will immediately terminate the
parent process and all children when in the "graceful" state. However
as the <code class="directive"><a href="/mod/mpm_common.html#pidfile">PidFile</a></code> will
have been removed, you will not be able to use
<code>apachectl</code> or <code>httpd</code> to send this signal,</p>
<div class="note"><p>The <code>graceful-stop</code> signal allows you to run multiple
identically configured instances of <code class="program"><a href="/programs/httpd.html">httpd</a></code> at the
same time. This is a powerful feature when performing graceful
upgrades of Apache, however it can also cause deadlocks and race
conditions with some configurations.</p>
<p>Care has been taken to ensure that on-disk files
such as the <code class="directive"><a href="/mod/core.html#lockfile">Lockfile</a></code> and <code class="directive"><a href="/mod/mod_cgid.html#scriptsock">ScriptSock</a></code> files contain the server
PID, and should co-exist without problem. However, if a configuration
directive, third-party module or persistent CGI utilises any other on-disk
lock or state files; care should be taken to ensure that multiple running
instances of <code class="program"><a href="/programs/httpd.html">httpd</a></code> do not clobber each others files.</p>
<p>You should also be wary of other potential race conditions, such as
using <code class="program"><a href="/programs/rotatelogs.html">rotatelogs</a></code> style piped logging. Multiple running
instances of <code class="program"><a href="/programs/rotatelogs.html">rotatelogs</a></code> attempting to rotate the same
logfiles at the same time may destroy each other's logfiles.</p></div>
</div></div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="/de/stopping.html" hreflang="de" rel="alternate" title="Deutsch">&nbsp;de&nbsp;</a> |
<a href="/en/stopping.html" title="English">&nbsp;en&nbsp;</a> |
<a href="/es/stopping.html" hreflang="es" rel="alternate" title="Espa�ol">&nbsp;es&nbsp;</a> |
<a href="/fr/stopping.html" hreflang="fr" rel="alternate" title="Fran�ais">&nbsp;fr&nbsp;</a> |
<a href="/ja/stopping.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
<a href="/ko/stopping.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
</div><div id="footer">
<p class="apache">Copyright 2007 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="/faq/">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p></div>
</body></html>