docs/manual/mod/perchild.html - httpd - Git at Google

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 <H1 ALIGN="CENTER">Multi-Processing Module perchild</H1>
 <P>
 This Multi-Processing Module allows for daemon processes serving requests
 to be assigned a variety of different userids.
 </P>

 <P><A
 HREF="module-dict.html#Status"
 REL="Help"
 ><STRONG>Status:</STRONG></A> MPM
 <BR>
 <A
 HREF="module-dict.html#SourceFile"
 REL="Help"
 ><STRONG>Source File:</STRONG></A> perchild.c
 <BR>
 <A
 HREF="module-dict.html#ModuleIdentifier"
 REL="Help"
 ><STRONG>Module Identifier:</STRONG></A> mpm_perchild_module
 </P>

 <H2>Summary</H2>

 <p>This Multi-Processing Module (MPM) implements a hybrid
 multi-process, multi-threaded web server.  A fixed number of processes
 create threads to handle requests.  Fluctuations in load are handled
 by increasing or decreasing the number of threads in each process.</p>

 <p>A single control process launches the number of child processes
 indicated by the <code>NumServers</code> directive at server startup.
 Each child process creates threads as specified in the
 <code>StartThreads</code> directive.  The individual threads then
 listen for connections and serve them when they arrive.</p>

 <p>Apache always tries to maintain a pool of <em>spare</em> or idle
 server threads, which stand ready to serve incoming requests.  In this
 way, clients do not need to wait for new threads to be created.  For
 each child process, Apache assesses the number of idle threads and
 creates or destroys threads to keep this number within the boundaries
 specified by <code>MinSpareThreads</code> and
 <code>MaxSpareThreads</code>.  Since this process is very
 self-regulating, it is rarely necessary to modify these directives
 from their default values.  The maximum number of clients that may be
 served simultaneously is determined by multiplying the number
 of server processes that will be created (<code>NumServers</code>) by
 the maximum number of threads created in each process
 (<code>MaxThreadsPerChild</code>).</p>

 <p>While the parent process is usually started as root under Unix in
 order to bind to port 80, the child processes and threads are launched
 by Apache as a less-privileged user.  The <code>User</code> and
 <code>Group</code> directives are used to set the privileges of the
 Apache child processes.  The child processes must be able to read all
 the content that will be served, but should have as few privileges
 beyond that as possible.  In addition, unless <a
 href="../suexec.html">suexec</a> is used, these directives also set
 the privileges which will be inherited by CGI scripts.</p>

 <p><code>MaxRequestsPerChild</code> controls how frequently the server
 recycles processes by killing old ones and launching new ones.</p>

 <p>See also: <a href="../bind.html">Setting which addresses and ports
 Apache uses</a>.</p>

 <p>In addition it adds the extra ability to specify that specific processes
 should serve requests under different userids.  These processes can
 then be associated with specific virtual hosts.</p>

 <!-- XXX: This desperately needs more explanation. -->


 <H2>Directives</H2>
 <UL>
 <li><a href="#assignuserid">AssignUserID</a></li>
 <li><a href="#childperuserid">ChildPerUserID</a></li>
 <li><a href="mpm_common.html#connectionstatus">ConnectionStatus</a></li>
 <li><a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li>
 <li><a href="mpm_common.html#group">Group</a></li>
 <li><a href="mpm_common.html#pidfile">PidFile</a></li>
 <li><a href="mpm_common.html#listen">Listen</a></li>
 <li><a href="mpm_common.html#listenbacklog">ListenBacklog</a></li>
 <li><a href="mpm_common.html#lockfile">LockFile</a></li>
 <li><a href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li>
 <li><a href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li>
 <li><a href="mpm_common.html#maxthreadsperchild">MaxThreadsPerChild</a></li>
 <li><a href="mpm_common.html#minsparethreads">MinSpareThreads</a></li>
 <li><a href="mpm_common.html#numservers">NumServers</a></li>
 <li><a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li>
 <li><a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li>
 <li><a href="mpm_common.html#startthreads">StartThreads</a></li>
 <li><a href="mpm_common.html#user">User</a></li>
 </UL>

 <hr>

 <H2><A NAME="assignuserid">AssignUserID directive</A></H2>
 <p><A
  HREF="directive-dict.html#Syntax"
  REL="Help"
 ><STRONG>Syntax:</STRONG></A><BR>
 <A
  HREF="directive-dict.html#Default"
  REL="Help"
 ><STRONG>Default:</STRONG></A><BR>
 <A
  HREF="directive-dict.html#Context"
  REL="Help"
 ><STRONG>Context:</STRONG></A> server config<BR>
 <A
  HREF="directive-dict.html#Status"
  REL="Help"
 ><STRONG>Status:</STRONG></A> MPM<BR>
 <A
  HREF="directive-dict.html#Module"
  REL="Help"
 ><STRONG>Module:</STRONG></A> perchild</p>

 <p>Tie a virtual host to a specific child process.</p>

 <hr>

 <H2><A NAME="childperuserid">ChilePerUserID directive</A></H2>
 <p><A
  HREF="directive-dict.html#Syntax"
  REL="Help"
 ><STRONG>Syntax:</STRONG></A><BR>
 <A
  HREF="directive-dict.html#Default"
  REL="Help"
 ><STRONG>Default:</STRONG></A><BR>
 <A
  HREF="directive-dict.html#Context"
  REL="Help"
 ><STRONG>Context:</STRONG></A> server config<BR>
 <A
  HREF="directive-dict.html#Status"
  REL="Help"
 ><STRONG>Status:</STRONG></A> MPM<BR>
 <A
  HREF="directive-dict.html#Module"
  REL="Help"
 ><STRONG>Module:</STRONG></A> perchild</p>

 <p>Specify a User and Group for a specific child process.</p>


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 </BODY>
 </HTML>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
	<HTML>
	<HEAD>
	<TITLE>Apache MPM perchild</TITLE>
	</HEAD>

	<!-- Background white, links blue (unvisited), navy (visited), red (active) -->
	<BODY
	BGCOLOR="#FFFFFF"
	TEXT="#000000"
	LINK="#0000FF"
	VLINK="#000080"
	ALINK="#FF0000"
	>
	<!--#include virtual="header.html" -->

	<H1 ALIGN="CENTER">Multi-Processing Module perchild</H1>
	<P>
	This Multi-Processing Module allows for daemon processes serving requests
	to be assigned a variety of different userids.
	</P>

	<P><A
	HREF="module-dict.html#Status"
	REL="Help"
	><STRONG>Status:</STRONG></A> MPM
	<BR>
	<A
	HREF="module-dict.html#SourceFile"
	REL="Help"
	><STRONG>Source File:</STRONG></A> perchild.c
	<BR>
	<A
	HREF="module-dict.html#ModuleIdentifier"
	REL="Help"
	><STRONG>Module Identifier:</STRONG></A> mpm_perchild_module
	</P>

	<H2>Summary</H2>

	<p>This Multi-Processing Module (MPM) implements a hybrid
	multi-process, multi-threaded web server. A fixed number of processes
	create threads to handle requests. Fluctuations in load are handled
	by increasing or decreasing the number of threads in each process.</p>

	<p>A single control process launches the number of child processes
	indicated by the <code>NumServers</code> directive at server startup.
	Each child process creates threads as specified in the
	<code>StartThreads</code> directive. The individual threads then
	listen for connections and serve them when they arrive.</p>

	<p>Apache always tries to maintain a pool of <em>spare</em> or idle
	server threads, which stand ready to serve incoming requests. In this
	way, clients do not need to wait for new threads to be created. For
	each child process, Apache assesses the number of idle threads and
	creates or destroys threads to keep this number within the boundaries
	specified by <code>MinSpareThreads</code> and
	<code>MaxSpareThreads</code>. Since this process is very
	self-regulating, it is rarely necessary to modify these directives
	from their default values. The maximum number of clients that may be
	served simultaneously is determined by multiplying the number
	of server processes that will be created (<code>NumServers</code>) by
	the maximum number of threads created in each process
	(<code>MaxThreadsPerChild</code>).</p>

	<p>While the parent process is usually started as root under Unix in
	order to bind to port 80, the child processes and threads are launched
	by Apache as a less-privileged user. The <code>User</code> and
	<code>Group</code> directives are used to set the privileges of the
	Apache child processes. The child processes must be able to read all
	the content that will be served, but should have as few privileges
	beyond that as possible. In addition, unless <a
	href="../suexec.html">suexec</a> is used, these directives also set
	the privileges which will be inherited by CGI scripts.</p>

	<p><code>MaxRequestsPerChild</code> controls how frequently the server
	recycles processes by killing old ones and launching new ones.</p>

	<p>See also: <a href="../bind.html">Setting which addresses and ports
	Apache uses</a>.</p>

	<p>In addition it adds the extra ability to specify that specific processes
	should serve requests under different userids. These processes can
	then be associated with specific virtual hosts.</p>

	<!-- XXX: This desperately needs more explanation. -->


	<H2>Directives</H2>
	<UL>
	<li><a href="#assignuserid">AssignUserID</a></li>
	<li><a href="#childperuserid">ChildPerUserID</a></li>
	<li><a href="mpm_common.html#connectionstatus">ConnectionStatus</a></li>
	<li><a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li>
	<li><a href="mpm_common.html#group">Group</a></li>
	<li><a href="mpm_common.html#pidfile">PidFile</a></li>
	<li><a href="mpm_common.html#listen">Listen</a></li>
	<li><a href="mpm_common.html#listenbacklog">ListenBacklog</a></li>
	<li><a href="mpm_common.html#lockfile">LockFile</a></li>
	<li><a href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li>
	<li><a href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li>
	<li><a href="mpm_common.html#maxthreadsperchild">MaxThreadsPerChild</a></li>
	<li><a href="mpm_common.html#minsparethreads">MinSpareThreads</a></li>
	<li><a href="mpm_common.html#numservers">NumServers</a></li>
	<li><a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li>
	<li><a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li>
	<li><a href="mpm_common.html#startthreads">StartThreads</a></li>
	<li><a href="mpm_common.html#user">User</a></li>
	</UL>

	<hr>

	<H2><A NAME="assignuserid">AssignUserID directive</A></H2>
	<p><A
	HREF="directive-dict.html#Syntax"
	REL="Help"
	><STRONG>Syntax:</STRONG></A><BR>
	<A
	HREF="directive-dict.html#Default"
	REL="Help"
	><STRONG>Default:</STRONG></A><BR>
	<A
	HREF="directive-dict.html#Context"
	REL="Help"
	><STRONG>Context:</STRONG></A> server config<BR>
	<A
	HREF="directive-dict.html#Status"
	REL="Help"
	><STRONG>Status:</STRONG></A> MPM<BR>
	<A
	HREF="directive-dict.html#Module"
	REL="Help"
	><STRONG>Module:</STRONG></A> perchild</p>

	<p>Tie a virtual host to a specific child process.</p>

	<hr>

	<H2><A NAME="childperuserid">ChilePerUserID directive</A></H2>
	<p><A
	HREF="directive-dict.html#Syntax"
	REL="Help"
	><STRONG>Syntax:</STRONG></A><BR>
	<A
	HREF="directive-dict.html#Default"
	REL="Help"
	><STRONG>Default:</STRONG></A><BR>
	<A
	HREF="directive-dict.html#Context"
	REL="Help"
	><STRONG>Context:</STRONG></A> server config<BR>
	<A
	HREF="directive-dict.html#Status"
	REL="Help"
	><STRONG>Status:</STRONG></A> MPM<BR>
	<A
	HREF="directive-dict.html#Module"
	REL="Help"
	><STRONG>Module:</STRONG></A> perchild</p>

	<p>Specify a User and Group for a specific child process.</p>





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