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diff --git a/rubbos/app/tomcat-connectors-1.2.32-src/docs/reference/workers.html b/rubbos/app/tomcat-connectors-1.2.32-src/docs/reference/workers.html deleted file mode 100644 index 68b996a7..00000000 --- a/rubbos/app/tomcat-connectors-1.2.32-src/docs/reference/workers.html +++ /dev/null @@ -1,1001 +0,0 @@ -<html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>The Apache Tomcat Connector - Reference Guide - workers.properties configuration</title><meta name="author" value="Mladen Turk"><meta name="email" value="mturk@apache.org"><link href="../style.css" type="text/css" rel="stylesheet"></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="4"><!--PAGE HEADER--><tr><td colspan="2"><!--TOMCAT LOGO--><a href="http://tomcat.apache.org/"><img src="../images/tomcat.gif" align="left" alt="Apache Tomcat" border="0"></a><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="http://www.apache.org/images/asf-logo.gif" align="right" alt="Apache Logo" border="0"></a></td></tr><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap="true"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li></ul><p><strong>Reference Guide</strong></p><ul><li><a href="../reference/workers.html">workers.properties</a></li><li><a href="../reference/uriworkermap.html">uriworkermap.properties</a></li><li><a href="../reference/status.html">Status Worker</a></li><li><a href="../reference/apache.html">Apache HTTP Server</a></li><li><a href="../reference/iis.html">IIS</a></li></ul><p><strong>Generic HowTo</strong></p><ul><li><a href="../generic_howto/quick.html">For the impatient</a></li><li><a href="../generic_howto/workers.html">All about workers</a></li><li><a href="../generic_howto/timeouts.html">Timeouts</a></li><li><a href="../generic_howto/loadbalancers.html">Load Balancing</a></li><li><a href="../generic_howto/proxy.html">Reverse Proxy</a></li></ul><p><strong>Webserver HowTo</strong></p><ul><li><a href="../webserver_howto/apache.html">Apache HTTP Server</a></li><li><a href="../webserver_howto/iis.html">IIS</a></li><li><a href="../webserver_howto/nes.html">Netscape/SunOne/Sun</a></li></ul><p><strong>AJP Protocol Reference</strong></p><ul><li><a href="../ajp/ajpv13a.html">AJPv13</a></li><li><a href="../ajp/ajpv13ext.html">AJPv13 Extension Proposal</a></li></ul><p><strong>Miscellaneous Documentation</strong></p><ul><li><a href="../miscellaneous/faq.html">Frequently asked questions</a></li><li><a href="../miscellaneous/changelog.html">Changelog</a></li><li><a href="http://issues.apache.org/bugzilla/buglist.cgi?query_format=advanced&short_desc_type=allwordssubstr&short_desc=&product=Tomcat+Connectors&long_desc_type=substring&long_desc=&bug_file_loc_type=allwordssubstr&bug_file_loc=&keywords_type=allwords&keywords=&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&emailassigned_to1=1&emailtype1=substring&email1=&emailassigned_to2=1&emailreporter2=1&emailcc2=1&emailtype2=substring&email2=&bugidtype=include&bug_id=&votes=&chfieldfrom=&chfieldto=Now&chfieldvalue=&cmdtype=doit&order=Reuse+same+sort+as+last+time&field0-0-0=noop&type0-0-0=noop&value0-0-0=">Current Tomcat Connectors bugs</a></li><li><a href="../miscellaneous/doccontrib.html">Contribute documentation</a></li><li><a href="../miscellaneous/jkstatustasks.html">JK Status Ant Tasks</a></li><li><a href="../miscellaneous/reporttools.html">Reporting Tools</a></li><li><a href="http://tomcat.apache.org/connectors-doc-archive/jk2/index.html">Old JK/JK2 documentation</a></li></ul><p><strong>News</strong></p><ul><li><a href="../news/20110701.html">2011</a></li><li><a href="../news/20100101.html">2010</a></li><li><a href="../news/20090301.html">2009</a></li><li><a href="../news/20081001.html">2008</a></li><li><a href="../news/20070301.html">2007</a></li><li><a href="../news/20060101.html">2006</a></li><li><a href="../news/20050101.html">2005</a></li><li><a href="../news/20041100.html">2004</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left"><table border="0" width="100%" cellspacing="4"><tr><td align="left" valign="top"><h1>The Apache Tomcat Connector - Reference Guide</h1><h2>workers.properties configuration</h2></td><td align="right" valign="top" nowrap="true"><small><a href="printer/workers.html"><img src="../images/printer.gif" border="0" alt="Printer Friendly Version"><br>print-friendly<br>version - </a></small></td></tr></table><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -A <b>Tomcat worker</b> is a Tomcat instance that is waiting to execute servlets or any other content -on behalf of some web server. For example, we can have a web server such as -Apache forwarding servlet requests to a Tomcat process (the worker) running behind it. -</p> -<p> -The scenario described above is a very simple one; -in fact one can configure multiple Tomcat workers to serve servlets on -behalf of a certain web server. -The reasons for such configuration can be: -</p> -<ul> -<li> -We want different contexts to be served by different Tomcat workers to provide a -development environment where all the developers share the same web server but -own a Tomcat worker of their own. -</li> -<li> -We want different virtual hosts served by different Tomcat processes to provide a -clear separation between sites belonging to different companies. -</li> -<li> -We want to provide load balancing, meaning run multiple Tomcat workers each on a -machine of its own and distribute the requests between them. -</li> -</ul> - -<p> -There are probably more reasons for having multiple workers but I guess that this list is enough... -</p> -<p> -Tomcat workers are defined in a properties file dubbed <b>workers.properties</b> and this tutorial -explains how to work with it. -</p> -</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Configuration File Basics"><strong>Configuration File Basics</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>Defining workers to the Tomcat web server plugin can be done using a properties file -(a sample file named workers.properties is available in the conf/ directory). -</p> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Format, Comments, Whitespace"><strong>Format, Comments, Whitespace</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -The lines in the file define properties. The general format is -</p> -<p><strong><name>=<value></strong></p> -<p> -</p> -Dots are used as part of the name to represent a configuration hierarchy. -<p> -Invalid directives will be logged during web server startup and prevent the web server -from working properly. Some directives have been deprecated. Although they will -still work, you should replace them by their -<a href="#Deprecated Worker Directives">successors</a>. -</p> -<p> -Some directives are allowed multiple times. This will be explicitly -noted in the tables below. -</p> -<p> -Whitespace at the beginning and the end of a property name or value gets ignored. -Comments can be placed in any line and start with a hash sign '#'. -Any line contents behind the hash sign get ignored. -</p> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Global Properties"><strong>Global Properties</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -These directives have global scope. -</p> -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="75%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><strong><code>worker.list</code></strong></td><td align="center" valign="center"><code>ajp13</code></td><td align="left" valign="center"> -A comma separated list of workers names that the JK will use. When starting up, -the web server plugin will instantiate the workers whose name appears in the -worker.list property, these are also the workers to whom you can map requests. -<p> -This directive can be used multiple times. -</p> -</td></tr><tr><td align="left" valign="center"><code>worker.maintain</code></td><td align="center" valign="center"><code>60</code></td><td align="left" valign="center"> -Worker connection pool maintain interval in seconds. If set to the positive -value JK will scan all connections for all workers specified in worker.list -directive and check if connections needs to be recycled. -<p> -Furthermore any load balancer does a global maintenance every worker.maintain -seconds. During global maintenance load counters are decayed and workers -in error are checked for recover_time. -</p> -<p> -This feature has been added in <b>jk 1.2.13</b>. -</p> -</td></tr></table> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Worker Properties"><strong>Worker Properties</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -Each worker configuration directive consists of three words separated by a dot: -</p> -<p><strong>worker.<worker name>.<directive>=<value></strong></p> -<p> -The first word is always <b>worker</b>. -The second word is the worker name you can choose. In the case of load-balancing, -the worker name has an additional meaning. Please consult the -<a href="../generic_howto/loadbalancers.html">Load Balancer HowTo</a>. -</p> -<p><font color="#ff0000"> -The name of the worker can contain only the alphanumeric characters -<b>[a-z][A-Z][0-9][_\-]</b> and is case sensitive. -</font></p> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Variables, Environment Variables"><strong>Variables, Environment Variables</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -You can define and use variables in the workers.properties file. -To define a variable you use the syntax: -</p> -<p><strong><variable_name>=<value></strong></p> -<p> -Dots are allowed in the variable name, but you have to be careful -not to use variable names, that clash with standard directives. -Therefore variable names should never start with "worker.". -</p> -<p> -To use a variable, you can insert "$(variable_name)" at any place -on the value side of a property line. If a variable has not been -defined before its use, we will search the process environment for -a variable with the same name and use their value. -</p> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Property Inheritance"><strong>Property Inheritance</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>Often one wants to use the same property values for various workers. -To reduce duplication of configuration lines and to ease the maintenance of -the file, you can inherit properties from one worker to another, or even -from a template to real workers. -</p> -<p> -The directive "reference" allows to copy configurations between workers -in a hierarchical way. If worker castor sets <b>worker.castor.reference=worker.pollux</b> -then it inherits all properties of <b>pollux</b>, except for the ones that -are explicitly set for <b>castor</b>. -</p> -<p> -Please note, that the value of the directive is not only the name of the referred worker, -but the complete prefix including "worker.". -</p> -<p> -To use a template worker simply define it like a real worker, but do not add it -to the "worker.list" or as a member to any load balancer. Such a template worker -does not have to contain mandatory directives. This approach is especially useful, -if one has a lot of balanced workers in a load balancer -and these workers share most of their properties. You can set all of these properties -in a template worker, e.g. using the prefix "worker.template1", and then simply -reference those common properties in all balanced workers. -</p> -<p> -References can be used to inherit properties over multiple hops in a hierarchical way. -</p> -<p> -This feature has been added in <b>jk 1.2.19</b>. -</p> -</blockquote></td></tr></table> -</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="List of All Worker Directives"><strong>List of All Worker Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Mandatory Directives"><strong>Mandatory Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>Mandatory directives are the one that each worker <b>must</b> contain. Without them the worker will -be unavailable or will misbehave. Those directives will be marked with a <strong>strong</strong> font in the following tables. -</p> -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="75%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><strong><code>type</code></strong></td><td align="center" valign="center"><code>ajp13</code></td><td align="left" valign="center"> -Type of the worker (can be one of ajp13, ajp14, jni, lb or status). The type of the worker -defines the directives that can be applied to the worker. -<p>AJP13 worker is the preferred worker type that JK uses for communication -between web server and Tomcat. This type of worker uses sockets as communication -channel. For detailed description of the AJP13 protocol stack browse to -<a href="../ajp/ajpv13a.html">AJPv13 protocol specification</a> -</p> -<p><font color="#ff0000">JNI workers have been deprecated. They will likely not work. Do not use them.</font></p> -</td></tr></table> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Connection Directives"><strong>Connection Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>Connection directives defines the parameters needed to connect and maintain -the connections pool of persistent connections between JK and remote Tomcat. -</p> -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="75%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>host</code></td><td align="center" valign="center"><code>localhost</code></td><td align="left" valign="center"> -Host name or IP address of the backend Tomcat instance. The remote Tomcat must -support the ajp13 protocol stack. The host name can have a <b>port</b> number -embedded separated by the colon (':') character. -</td></tr><tr><td align="left" valign="center"><code>port</code></td><td align="center" valign="center"><code>8009</code></td><td align="left" valign="center"> -Port number of the remote Tomcat instance listening for defined protocol requests. -The default value depends on the worker type. For AJP13 workers the default port is -<b>8009</b>, while for AJP14 type of worker that value is <b>8011</b>. -</td></tr><tr><td align="left" valign="center"><code>socket_timeout</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Socket timeout in seconds used for the communication channel between JK and remote host. -If the remote host does not respond inside the timeout specified, JK will generate an error, -and retry again. If set to zero (default) JK will wait for an infinite amount of time -on all socket operations. -</td></tr><tr><td align="left" valign="center"><code>socket_connect_timeout</code></td><td align="center" valign="center"><code>socket_timeout*1000</code></td><td align="left" valign="center"> -Socket connect timeout in milliseconds used for the communication channel between JK and remote host. -If the remote host does not respond inside the timeout specified, JK will generate an error, -and retry again. -<p> -Note that <b class="code">socket_timeout</b> is in seconds, and -<b class="code">socket_connect_timeout</b> in milliseconds, -so in absolute terms the default <b class="code">socket_connect_timeout</b> is -equal to <b class="code">"socket_timeout</b>. -</p> -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>socket_keepalive</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -This directive should be used when you have a firewall between your webserver -and the Tomcat engine, who tend to drop inactive connections. This flag will tell the Operating System -to send <b class="code">KEEP_ALIVE</b> messages on inactive connections (interval depend on global OS settings, -generally 120 minutes), and thus prevent the firewall to cut inactive connections. -To enable keepalive set this property value to <b>True</b>. -<p> -The problem with Firewall cutting inactive connections is that sometimes, neither webserver or Tomcat -have information about the cut and couldn't handle it. -</p> -</td></tr><tr><td align="left" valign="center"><code>ping_mode</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -This flag determines, under which conditions established -connections are probed to ensure they are still working. -The probe is done with an empty AJP13 packet (CPing) and -expects to receive an appropriate answer (CPong) within -some timeout. -<p> -The value of the flag can be any combination of the following -flags (multiple values are combined without any separators): -</p> -<p><b>C</b> (connect): If set, the connection will -be probed once after connecting to the backend. The timeout -can be set by <b class="code">connect_timeout</b>. If it is not set, -the value of <b class="code">ping_timeout</b> will be used instead. -</p> -<p><b>P</b> (prepost): If set, the connection will -be probed before sending each request to the backend. The timeout -can be set by <b class="code">prepost_timeout</b>. If it is not set, -the value of <b class="code">ping_timeout</b> will be used instead. -</p> -<p><b>I</b> (interval): If set, the connection will -be probed during the regular internal maintenance cycle, -but only if it is idle longer than -<b class="code">connection_ping_interval</b>. The timeout -can be set by <b class="code">ping_timeout</b>. -</p> -<p><b>A</b> If set, all of the above probes will be used. -</p> -<p> -This feature has been added in <b>jk 1.2.27</b>. Connect and -prepost probing were already available via <b class="code">connect_timeout</b> -and <b class="code">prepost_timeout</b> since version <b>jk 1.2.6</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>ping_timeout</code></td><td align="center" valign="center"><code>10000</code></td><td align="left" valign="center"> -Timeout in milliseconds used when waiting for the CPong answer of a -CPing connection probe. The activation of the probes is done via -<b class="code">ping_mode</b>. The timeouts for <b class="code">ping_mode</b> -connect and prepost can be overwritten individually via -<b class="code">connect_timeout</b> and <b class="code">prepost_timeout</b>. -<p> -For compatibility reasons, CPing/CPong is also used, whenever -<b class="code">connect_timeout</b> or <b class="code">prepost_timeout</b> are set, -even if <b class="code">ping_mode</b> is empty. -</p> -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>connection_ping_interval</code></td><td align="center" valign="center"><code>0 / (ping_timeout/1000)*10</code></td><td align="left" valign="center"> -When using interval connection probing, connections idle for longer than this -interval in seconds are probed by CPing packets whether they still work. -<p>Interval probing can be activated either by <b class="code">ping_mode</b>, -or by setting <b class="code">connection_ping_interval</b> to some value bigger -than zero. If you activate interval probing via <b class="code">ping_mode</b>, -then the default value of <b class="code">connection_ping_interval</b> is -<b class="code">(ping_timeout/1000) * 10</b>. Note that <b class="code">ping_timeout</b> -is in milliseconds, and <b class="code">connection_ping_interval</b> in seconds, -so in absolute terms the default <b class="code">connection_ping_interval</b> is -10 times <b class="code">ping_timeout</b>. -</p> -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>connection_pool_size</code></td><td align="center" valign="center"><code>see text</code></td><td align="left" valign="center"> -This defines the number of connections made to the AJP backend that -are maintained as a connection pool. -It will limit the number of those connection that each web server child -process can made. -<p> -Connection pool size property is only used for multi threaded -web servers such as Apache, IIS and Netscape/Sun. The connection_pool_size property -needs to reflect the number of requests one web server process should -be able to send to a backend in parallel. Usually this is the same as -the number of threads per web server process. JK will discover -this number for the Apache web server automatically and set the pool size to -this value. For IIS the default value is 250 (before version 1.2.20: 10), -for Netscape/Sun the default value is 1. -</p> -<p>We strongly recommend adjusting this value for IIS and the Netscape/Sun -to the number of requests one web server process should -be able to send to a backend in parallel. You should measure how many connections -you need during peak activity without performance problems, and then add some -percentage depending on your growth rate. Finally you should check, -whether your web server processes are able to use at least as many threads, -as you configured as the pool size. -</p> -<p><font color="#ff0000">Do not use connection_pool_size with values higher then 1 on <b>Apache 2.x prefork</b> or <b>Apache 1.3.x</b>!</font></p> -</td></tr><tr><td align="left" valign="center"><code>connection_pool_minsize</code></td><td align="center" valign="center"><code>(pool+1)/2</code></td><td align="left" valign="center"> -Minimum size of the connection pool that will be maintained. -<p> -Its default value is (connection_pool_size+1)/2. -</p> -<p><font color="#ff0000">Do not use connection_pool_size with values higher then 1 on <b>Apache 2.x prefork</b> or <b>Apache 1.3.x</b>!</font></p> -<p> -This feature has been added in <b>jk 1.2.16</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>connection_pool_timeout</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Cache timeout property should be used with <b>connection_pool_minsize</b> to specify how many seconds JK should keep -an inactive socket in cache before closing it. This property should be used to reduce the number of threads -on the Tomcat web server. The default value zero disables the closing (infinite timeout). -<p> -Each child could open an ajp13 connection if it has to forward a request to Tomcat, creating -a new ajp13 thread on Tomcat side. -</p> -<p> -The problem is that after an ajp13 connection is created, the child won't drop it -until killed. And since the webserver will keep its childs/threads running -to handle high-load, even it the child/thread handle only static contents, you could -finish having many unused ajp13 threads on the Tomcat side. -</p> -<p> -You should keep this time interval in sync with the <b>connectionTimeout</b> attribute -of your AJP connector in Tomcat's server.xml. Note however, that the value -for mod_jk is given in seconds, the one in server.xml has to use milliseconds. -</p> -</td></tr><tr><td align="left" valign="center"><code>connection_acquire_timeout</code></td><td align="center" valign="center"><code>retries*retry_interval</code></td><td align="left" valign="center"> -Timeout the worker will wait for a free socket in cache before giving up. -<p> -Its default value is <b>retries * retry_interval</b>. -</p> -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>lbfactor</code></td><td align="center" valign="center"><code>1</code></td><td align="left" valign="center"> -Only used for a member worker of a load balancer. -<p> -The integer number lbfactor (load-balancing factor) is -<i>how much we expect this worker to work</i>, or -<i>the worker's work quota</i>. Load balancing factor is compared with other workers -that makes the load balancer. For example if one worker has lb_factor 5 times higher then -other worker, then it will receive five times more requests. -</p> -</td></tr></table> - -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Load Balancing Directives"><strong>Load Balancing Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>Load balancer is a virtual worker that does not really communicate with Tomcat workers. -Instead it is responsible for the management of several "real" workers. -The worker is supposed to be a load balancer if it's worker type is <b>lb</b>. -See worker's <b>type</b> directive. -</p> -<p>Loadbalancer directives define the parameters needed to create the workers that are -connecting to a remote cluster of backend Tomcat servers. Each cluster node has to -have a worker defined. -</p> -<p> -Load balancer management includes: -</p> - -<ul> -<li> -Instantiating the workers in the web server. -</li> -<li> -Using the worker's load-balancing factor, perform weighed-round-robin load balancing where -high lbfactor means stronger machine (that is going to handle more requests) -</li> -<li> -Keeping requests belonging to the same session executing on the same Tomcat worker. -</li> -<li> -Identifying failed Tomcat workers, suspending requests to them and instead fall-backing on -other workers managed by the lb worker. -</li> -</ul> - -<p> -The overall result is that workers managed by the same lb worker are load-balanced -(based on their lbfactor and current user session) and also fall-backed so a single -Tomcat process death will not "kill" the entire site. -</p> -<p><font color="#ff0000"> -If you want to use session stickiness, you must set different jvmRoute attributes -in the Engine element in Tomcat's server.xml. Furthermore the names of the workers -which are managed by the balancer have to be equal to the jvmRoute of the Tomcat -instance they connect with. -</font></p> -<p> -The restriction on the worker names can be lifted, if you use the route attribute for the workers. -</p> -<p> -The following table specifies properties that the lb worker can accept: -</p> - -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="75%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><strong><code>balance_workers</code></strong></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -A comma separated list of workers that the load balancer -need to manage. -<p> -This directive can be used multiple times for the same load balancer. -</p> -<p> -This directive replaces old <b>balanced_workers</b> directive and -can be used only with mod_jk versions 1.2.7 and up. -</p> -<p><font color="#ff0000">As long as these workers should only be used via the load balancer worker, -there is no need to also put them into the <b>worker.list</b> property.</font></p> -</td></tr><tr><td align="left" valign="center"><code>sticky_session</code></td><td align="center" valign="center"><code>True</code></td><td align="left" valign="center"> -Specifies whether requests with SESSION ID's should be routed back to the same -Tomcat worker. If sticky_session is set to <b>True</b> or <b>1</b> sessions are sticky, otherwise -sticky_session is set to <b>False</b>. Set sticky_session to <b>False</b> when Tomcat -is using a Session Manager which can persist session data across multiple -instances of Tomcat. -</td></tr><tr><td align="left" valign="center"><code>sticky_session_force</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -Specifies whether requests with SESSION ID's for workers that are in error state -should be rejected. If sticky_session_force is set to <b>True</b> or <b>1</b> -and the worker that matches that SESSION ID is in error state, client will -receive 500 (Server Error). If set to <b>False</b> or <b>0</b> failover on -another worker will be issued with loosing client session. This directive is -used only when you set <b>sticky_session=True</b>. -<p> -This feature has been added in <b>jk 1.2.9</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>method</code></td><td align="center" valign="center"><code>Request</code></td><td align="left" valign="center"> -Specifies what method load balancer is using for electing the best worker. -Please note, that session stickiness and perfect load balancing are -conflicting targets, especially when the number -of sessions is small, or the usage of sessions is extremely varying -For huge numbers of sessions this usually is not a problem. -<p> -Some methods note, that they aggregate in a sliding time window. They add up -accesses, and on each run of the global maintain method, the load counters -get divided by 2. Usually this happens once a minute, depending on the -setting of worker.maintain. The value of the load counters can be inspected -using the status worker. -</p> -<p> -If method is set to <b>R[equest]</b> the balancer will use number of requests -to find the best worker. Accesses will be distributed according to the -lbfactor in a sliding time window. This is the default value and should be -working well for most applications. -</p> -<p> -If method is set to <b>S[ession]</b> the balancer will use number of sessions -to find the best worker. Accesses will be distributed according to the -lbfactor in a sliding time window. Because the balancer does not keep any state, -it actually does not know the number of sessions. Instead it counts each request -without a session cookie or URL encoding as a new session. This method will neither -know, when a session is being invalidated, nor will it correct its load numbers -according to session timeouts or worker failover. This method should be used, -if sessions are your limiting resource, e.g. when you only have limited memory -and your sessions need a lot of memory. -</p> -<p> -If set to <b>T[raffic]</b> the balancer will use -the network traffic between JK and Tomcat to find the best worker. -Accesses will be distributed according to the lbfactor in a sliding time window. -This method should be used, if network to and from the backends is your -limiting resource. -</p> -<p> -If set to <b>B[usyness]</b> the balancer will -pick the worker with the lowest current load, based on how many requests the -worker is currently serving. This number is divided by the workers lbfactor, -and the lowest value (least busy) worker is picked. This method is especially -interesting, if your request take a long time to process, like for a download -application. -</p> -<p> -This feature has been added in <b>jk 1.2.9</b>. -The Session method has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>lock</code></td><td align="center" valign="center"><code>Optimistic</code></td><td align="left" valign="center"> -Specifies what lock method the load balancer will use for synchronising -shared memory runtime data. -If lock is set to <b>O[ptimistic]</b> balancer will not use shared memory lock -to find the best worker. If set to <b>P[essimistic]</b> balancer will use -shared memory lock. The balancer will work more accurately in case of -Pessimistic locking, but can slow down the average response time. -<p> -This feature has been added in <b>jk 1.2.13</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>retries</code></td><td align="center" valign="center"><code>2</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive also exists for normal workers. -For those it has a <a href="#Advanced Worker Directives">different meaning</a>.</font></p> -If the load balancer can not get a valid member worker or in case of failover, -it will try again a number of times given by <b>retries</b>. -Before each retry, it will make a pause define by <b>retry_interval</b> directive. -<p> -Until version <b>1.2.16</b> the default value was 3. -</p> -</td></tr></table> - -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Status Worker Directives"><strong>Status Worker Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -The status worker does not communicate with Tomcat. -Instead it is responsible for the load balancer management. -</p> -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="75%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>css</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -Specifies the url for cascading stylesheet to use. -</td></tr><tr><td align="left" valign="center"><code>read_only</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -A status worker with read_only=True will not allow any operations, -that change the runtime state or configuration of the other workers. -These are edit/update/reset/recover. -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>user</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -It is a list of users -which gets compared to the user name authenticated by the web server. -If the name is not contained in this list, access is denied. Per -default the list is empty and then access is allowed to anybody. -<p> -This directive can be used multiple times. -</p> -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>user_case_insensitive</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -By default, the user names are matched case sensitively. You can set -user_case_insensitive=True to make the comparison case insensitive. -This may be especially useful on the Windows platform. -<p> -This feature has been added in <b>jk 1.2.21</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>good</code></td><td align="center" valign="center"><code>a.o,a.n,a.b,a.r</code></td><td align="left" valign="center"> -For every load balancer worker, the status worker shows a summary -of the state of its members. There are three such states, -"good", "bad" and "degraded". -<p> -These states are determined depending on the activation of the members -(active, disabled, stopped) and their runtime state -(ok, n/a, busy, recovering, probing, forced recovery, error). -By default, members are assumed to be "good", if their activation -is "active" and their runtime state is not "error". -</p> -<p> -You can change this mapping, by assigning a list of values to the -attribute "good". Each value gives a possible match for the members, -and one match suffices. Each value is either a single character, or two -characters combined with a dot ".". The single characters are the -first characters in the words "active", "disabled", "stopped", -"ok", "na", "busy", "recovering", "error". The additional states "probing" -and "forced recovery" are always rated equivalent to "recovering". -If a value consists only -of a single character, then all members with this activation or runtime -state will be assumed good. A combination of an activation and a runtime -state concatenated with a dot "." does only apply to a member, that has -exactly this activation and state. -</p> -<p> -Members of a load balancer will first be matched against the state "bad", -if they don't match, the state "good" will be tried, and if they -still don't match, their state will be "degraded". -</p> -<p> -This directive can be used multiple times. -</p> -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>bad</code></td><td align="center" valign="center"><code>s,e</code></td><td align="left" valign="center"> -See: "good". -<p> -By default, members are assumed to be "bad", if their activation -is "stopped" or their runtime state is "error". -</p> -<p> -This directive can be used multiple times. -</p> -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>prefix</code></td><td align="center" valign="center"><code>worker</code></td><td align="left" valign="center"> -The prefix, which will be used by the status worker -when producing properties output (mime=prop). -Each property key will be prefixed by this value. -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>ns</code></td><td align="center" valign="center"><code>jk:</code></td><td align="left" valign="center"> -This directive can be used to customise the XML output from the -status worker. If set to <b>-</b> no namespace will be used. -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>xmlns</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -This directive can be used to customise the XML output from the -status worker. If set to <b>-</b> no xmlns will be used. -<p> -Default value is set to xmlns:jk="http://tomcat.apache.org" -</p> -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>doctype</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -This directive can be used to customise the XML output from the -status worker. This value will be inserted to the output xml -after the xml header. -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -</td></tr></table> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Advanced Worker Directives"><strong>Advanced Worker Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p> -This table lists more advanced configuration options. Most of them only apply to -some types of workers. We use the abbreviations <b>AJP</b> for ajp13/ajp14 workers -used directly via the workers.list, <b>LB</b> for load balancer workers, -and <b>SUB</b> for the workers used indirectly in a load balancer worker -as a sub worker or member. -</p> -<table border="1" cellpadding="5"><tr><th width="10%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Worker Type</font></th><th width="8%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="72%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>connect_timeout</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Connect timeout property told webserver to send a PING request on ajp13 connection after -connection is established. The parameter is the delay in milliseconds to wait for the PONG reply. -The default value zero disables the timeout (infinite timeout). -<p> -This features has been added in <b>jk 1.2.6</b> to avoid problem with hung Tomcat's and require ajp13 -ping/pong support which has been implemented on Tomcat <b>3.3.2+, 4.1.28+ and 5.0.13+</b>. -Disabled by default. -</p> -</td></tr><tr><td align="left" valign="center"><code>prepost_timeout</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Prepost timeout property told webserver to send a PING request on ajp13 connection before -forwarding to it a request. The parameter is the delay in milliseconds to wait for the PONG reply. -The default value zero disables the timeout (infinite timeout). -<p> -This features has been added in <b>jk 1.2.6</b> to avoid problem with hung Tomcat's and require ajp13 -ping/pong support which has been implemented on <b>Tomcat 3.3.2+, 4.1.28+ and 5.0.13+</b>. -Disabled by default. -</p> -</td></tr><tr><td align="left" valign="center"><code>reply_timeout</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -The parameter is the number of milliseconds to wait for success during a read event. -So this is not a timeout for the complete answer time of a request, but only -for the maximum time between two packets received from Tomcat. Usually the longest -pause is between sending the request and getting the first packet of the response. -<p> -If the timeout passes without any data received from Tomcat, the webserver will -no longer wait for the rest of the response and send an error to the client (browser). -Usually this does not mean, that the request is also aborted on the Tomcat backend. -If the worker is a member of a load balancer, the load balancer might place the -worker into an error state and retry the request on another member. -See also <b>max_reply_timeouts</b>, <b>retries</b> and <b>recovery_options</b>. -</p> -<p> -By default (value zero) the webserver will wait forever which could be an issue for you. -If you set a reply_timeout, adjust it carefully if you have long running servlets. -</p> -<p> -The reply_timeout can be overwritten using the Apache httpd environment variable -JK_REPLY_TIMEOUT. -</p> -<p> -This features has been added in <b>jk 1.2.6</b> to avoid problem with hung Tomcat's and works on all -servlet engines supporting ajp13. The variable JK_REPLY_TIMEOUT has been added in version <b>1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>retries</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>2</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive also exists for load balancer workers. -For those it has a <a href="#Load Balancing Directives">different meaning</a>.</font></p> -The maximum number of times that the worker will send a request to Tomcat -in case of a communication error. Each retry will be done over another -connection. The first time already gets counted, so retries=2 means -one retry after error. Before a retry, the worker waits for a configurable -sleeping time. -<p> -See also the attribute <b>recovery_options</b> for a more fine-grained control -of retries and <b>retry_interval</b> for the sleep time configuration. -</p> -<p> -Until version <b>1.2.16</b> the default value was 3. -</p> -</td></tr><tr><td align="left" valign="center"><code>retry_interval</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>100</code></td><td align="left" valign="center"> -The amount of time in milliseconds the worker sleeps before doing any retry. -<p> -This features has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>recovery_options</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Recovery options influence, how we should handle retries, -in case we detect a problem with Tomcat. -How often we will retry is controlled by the attribute <b>retries</b>. -<p> -This attribute is a bit mask. The following bits are allowed:<br> -1: don't recover if Tomcat failed after getting the request<br> -2: don't recover if Tomcat failed after sending the headers to client<br> -4: close the connection to Tomcat, if we detect an error when writing back -the answer to the client (browser)<br> -8: always recover requests for HTTP method HEAD (even if Bits 1 or 2 are set)<br> -16: always recover requests for HTTP method GET (even if Bits 1 or 2 are set)<br> -</p> -<p> -This features has been added in <b>jk 1.2.6</b>. -Option 4 has been added in version <b>1.2.16</b>, -options 8 and 16 in version <b>1.2.24</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>fail_on_status</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -Set this value to the HTTP status code that will cause a worker to fail -if returned from Servlet container. Use this directive to deal with -cases when the servlet container can temporary return non-200 responses -for a short amount of time, e.g during redeployment. -<p> -The error page, headers and status codes of the original response will not be send back -to the client. Instead the request will result in a 503 response. -If the worker is a member of a load balancer, the member will -be put into an error state. Request failover and worker recovery will be handled -with the usual load balancer procedures. -</p> -<p> -This feature has been added in <b>jk 1.2.20</b>. -</p> -<p> -Starting with <b>jk 1.2.22</b> it is possible to define multiple -status codes separated by space or comma characters. -For example: <b class="code">worker.xxx.fail_on_status=500,503</b> -</p> -<p> -Starting with <b>jk 1.2.25</b> you can also tell the load -balancer to not put a member into an error state, if a -response returned with one of the status codes in -fail_on_status. This feature gets enabled, by putting a minus sign in -front of those status codes. -For example: <b class="code">worker.xxx.fail_on_status=-404,-500,503</b> -</p> -</td></tr><tr><td align="left" valign="center"><code>max_packet_size</code></td><td align="left" valign="center"><code>AJP,SUB</code></td><td align="center" valign="center"><code>8192</code></td><td align="left" valign="center"> -This attribute sets the maximal AJP packet size in Bytes. -The maximum value is 65536. If you change it from the default, -you <b>must</b> also change the packetSize attribute of your AJP -connector on the Tomcat side! The attribute packetSize is only available -in Tomcat 5.5.20+ and 6.0.2+. -<p> -Normally it is not necessary to change the maximum packet size. Problems -with the default value have been reported when sending certificates or -certificate chains. -</p> -<p> -This feature has been added in <b>jk 1.2.19</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>mount</code></td><td align="left" valign="center"><code>AJP,LB</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -Space delimited list of uri maps the worker should handle. It is only used, -if the worker is included in worker.list. -<p> -This directive can be used multiple times for the same worker. -</p> -</td></tr><tr><td align="left" valign="center"><code>secret</code></td><td align="left" valign="center"><code>AJP,LB,SUB</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -You can set a secret keyword on the Tomcat AJP Connector. Then only requests -from workers with the same secret keyword will be accepted. -<p> -Use <b>request.secret="secret key word"</b> in your Tomcat AJP Connector configuration. -</p> -<p> -If you set a secret on a load balancer, all its members will inherit this secret. -</p> -<p> -This feature has been added in <b>jk 1.2.12</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>max_reply_timeouts</code></td><td align="left" valign="center"><code>LB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -If you use a <b>reply_timeout</b> for the members of a load balancer worker, -and you want to tolerate a few requests taking longer than reply_timeout, -you can set this attribute to some positive value. -<p> -Long running requests will still time out after reply_timeout milliseconds waiting for -data, but the corresponding member worker will only be put into an error state, -if more than <b>max_reply_timeouts</b> requests have timed out. -More precisely, the counter for those bad requests will be divided by two, -whenever the load balancer does its internal maintenance (by default every 60 -seconds). -</p> -<p> -This features has been added in <b>jk 1.2.24</b> to make <b>reply_timeout</b> less -sensitive for sporadic long running requests. -</p> -</td></tr><tr><td align="left" valign="center"><code>recover_time</code></td><td align="left" valign="center"><code>LB</code></td><td align="center" valign="center"><code>60</code></td><td align="left" valign="center"> -The recover time is the time in seconds the load balancer will not try -to use a worker, after it went into error state. Only after this time has passed, -a worker in error state will be marked as in recovering, so that it will be -tried for new requests. -<p> -This interval is not checked every time a request is being processed. -Instead it is being checked during global maintenance. The time between two -runs of global maintenance is controlled by worker.maintain. -</p> -<p> -Do not set recover_time to a very short time unless you understand the implications. -Every recovery attempt for a worker in error is done by a real request! -</p> -</td></tr><tr><td align="left" valign="center"><code>error_escalation_time</code></td><td align="left" valign="center"><code>LB</code></td><td align="center" valign="center"><code>recover_time / 2</code></td><td align="left" valign="center"> -Setting a member of a load balancer into an error state is quite serious. E.g. -it means that if you need stickyness, all access to the sessions of the -respective node is blocked. -<p> -Some types of error detection do not provide a precise information, whether -a node is completely broken or not. In those cases an LB will not immediately -put the node into the error state. Only when there have been no successful -responses for <b>error_escalation_time</b> seconds after such an error, -will the node be put into error state. -</p> -<p> -This features has been added in <b>jk 1.2.28</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>activation</code></td><td align="left" valign="center"><code>SUB</code></td><td align="center" valign="center"><code>Active</code></td><td align="left" valign="center"> -Using this directive, a balanced worker of a load balancer -can be configured as disabled or stopped. A disabled worker only gets -requests, which belong to sessions for that worker. A stopped -worker does not get any requests. Users of a stopped worker will -loose their sessions, unless session replication via clustering is used. -<p> -Use <b>d</b> or <b>D</b> to disable and <b>s</b> or <b>S</b> to stop. -If this directive is not present the deprecated directives -"disabled" or "stopped" are used. -</p> -<p> -This flag can be changed at runtime using status worker. -</p> -<p> -This feature has been added in <b>jk 1.2.19</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>route</code></td><td align="left" valign="center"><code>SUB</code></td><td align="center" valign="center"><code>worker name</code></td><td align="left" valign="center"> -Normally the name of a balanced worker in a load balancer is equal to the jvmRoute -of the corresponding Tomcat instance. If you want to include a worker corresponding -to a Tomcat instance into several load balancers with different balancing configuration -(e.g. disabled, stopped) you can use this attribute. -<p> -Define a separate worker per lb and per Tomcat instance with an arbitrary worker name and -set the route attribute of the worker equal to the jvmRoute of the target Tomcat instance. -</p> -<p> -If this attribute is left empty, the name of the worker will be used. -</p> -<p> -This attribute can be changed at runtime using status worker. -</p> -<p> -If the route name contains a period, the part before the first period will be -used as domain name, unless domain is set explicitly. -</p> -<p> -This feature has been added in <b>jk 1.2.16</b>.<br> -The automatic domain rule has been added in <b>jk 1.2.20</b>.<br> -The attribute has been renamed from jvm_route to route in <b>jk 1.2.20</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>distance</code></td><td align="left" valign="center"><code>SUB</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -An integer number to express preferences between -the balanced workers of an lb worker. -A load balancer will never choose some balanced worker -in case there is another usable worker with lower distance. -<p> -Only in case all workers below a given distance are in error, disabled or stopped, -workers of a larger distance are eligible for balancing. -</p> -<p> -This feature has been added in <b>jk 1.2.16</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>domain</code></td><td align="left" valign="center"><code>SUB</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -Domain directive can be used only when the worker is a member of the load balancer. -Workers that share the same domain name are treated as single worker. If sticky_session -is used, then the domain name is used as session route. -<p> -This directive is used for large system with more then 6 Tomcats, to be able -to cluster the Tomcats in two groups and thus lowering the session replication -transfer between them. -</p> -<p> -This feature has been added in <b>jk 1.2.8</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>redirect</code></td><td align="left" valign="center"><code>SUB</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -Set to the name of the preferred failover worker. If worker matching -SESSION ID is in error state then the redirect worker will be used instead. -It will be used even if being disabled, thus offering hot standby. -<p> -If you explicitly set a route via the "route" attribute, you must set "redirect" -to this route of the preferred failover worker and not to its name. -</p> -<p> -This feature has been added in <b>jk 1.2.9</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>session_cookie</code></td><td align="left" valign="center"><code>LB</code></td><td align="center" valign="center"><code>JSESSIONID</code></td><td align="left" valign="center"> -The name of the cookie that contains the routing identifier needed for session stickyness. -The routing identifier is everything after a "." character in the value of the cookie. -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>session_path</code></td><td align="left" valign="center"><code>LB</code></td><td align="center" valign="center"><code>;jsessionid</code></td><td align="left" valign="center"> -The name of the path parameter that contains the routing identifier needed for -session stickyness. The routing identifier is everything after a "." character in the value -of the path parameter. -<p> -This feature has been added in <b>jk 1.2.27</b>. -</p> -</td></tr></table> -</blockquote></td></tr></table> - -<table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Deprecated Worker Directives"><strong>Deprecated Worker Directives</strong></a></font></td></tr><tr><td><blockquote> -<br> -<p>The following directives have been deprecated in the past. We include their documentation -in case you need to use an older version of mod_jk. We urge you to update and not use -them any more. Please migrate your existing configurations. -</p> -<table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Directive</font></th><th width="15%" bgcolor="#023264"><font color="#ffffff">Successor</font></th><th width="10%" bgcolor="#023264"><font color="#ffffff">Default</font></th><th width="60%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code>cachesize</code></td><td align="center" valign="center"><code>connection_pool_size</code></td><td align="center" valign="center"><code>see text</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.16.</font></p> -Cachesize defines the number of connections made to the AJP backend that -are maintained as a connection pool. -It will limit the number of those connection that each web server child -process can make. -<p> -Cachesize property is used only for multi threaded -web servers such as Apache 2.0 (worker), IIS and Netscape. The cachesize property -should reflect the number of threads per child process. JK will discover -the number of threads per child process on Apache 2 web server with worker-mpm and set -its default value to match the ThreadsPerChild Apache directive. For IIS the default -value is 10. For other web servers than Apache or IIS this value has to be set manually. -</p> -<p><font color="#ff0000">Do not use cachesize with values higher then 1 on <b>Apache 2.x prefork</b> or <b>Apache 1.3.x</b>!</font></p> -</td></tr><tr><td align="left" valign="center"><code>cache_timeout</code></td><td align="center" valign="center"><code>connection_pool_timeout</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.16.</font></p> -Cache timeout property should be used with <b>cachesize</b> to specify how to time JK should keep -an open socket in cache before closing it. This property should be used to reduce the number of threads -on the Tomcat web server. -<p> -Each child could open an ajp13 connection if it have to forward a request to Tomcat, creating -a new ajp13 thread on Tomcat side. -</p> -<p> -The problem is that after an ajp13 connection is created, the child won't drop it -until killed. And since the webserver will keep its childs/threads running -to handle high-load, even it the child/thread handle only static contents, you could -finish having many unused ajp13 threads on the Tomcat side. -</p> -</td></tr><tr><td align="left" valign="center"><code>recycle_timeout</code></td><td align="center" valign="center"><code>connection_pool_timeout</code></td><td align="center" valign="center"><code>0</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.16.</font></p> -The number of seconds that told webserver to cut an ajp13 connection after some time of -inactivity. When choosing an endpoint for a request and the assigned socket is open, it will be -closed if it was not used for the configured time. -It's a good way to ensure that there won't too old threads living on Tomcat side, -with the extra cost you need to reopen the socket next time a request be forwarded. -This property is very similar to <b>cache_timeout</b> but works also in non-cache mode. -If set to value zero (default) no recycle will took place. -</td></tr><tr><td align="left" valign="center"><code>balanced_workers</code></td><td align="center" valign="center"><code>balance_workers</code></td><td align="center" valign="center"><code>-</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.7.</font></p> -A comma separated list of workers that the load balancer -need to manage. -</td></tr><tr><td align="left" valign="center"><code>disabled</code></td><td align="center" valign="center"><code>activation</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.19.</font></p> -If set to <b>True</b> or <b>1</b> the worker will be disabled if member -of load balancer. This flag can be changed at runtime using status worker. -<p> -This feature has been added in <b>jk 1.2.9</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>stopped</code></td><td align="center" valign="center"><code>activation</code></td><td align="center" valign="center"><code>False</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.19.</font></p> -If set to <b>True</b> or <b>1</b> the worker will be stopped if member -of load balancer. The flag is needed for stop complete traffic of a sticky session -worker. It is only useful, when you have a cluster that replicated the sessions. -This flag can be changed at runtime using status worker. -<p> -This feature has been added in <b>jk 1.2.11</b>. -</p> -</td></tr><tr><td align="left" valign="center"><code>jvm_route</code></td><td align="center" valign="center"><code>route</code></td><td align="center" valign="center"><code>worker name</code></td><td align="left" valign="center"> -<p><font color="#ff0000">This directive has been deprecated since 1.2.20.</font></p> -Normally the name of a balanced worker in a load balancer is equal to the jvmRoute -of the corresponding Tomcat instance. If you want to include a worker corresponding -to a Tomcat instance into several load balancers with different balancing configuration -(e.g. disabled, stopped) you can use this attribute. -<p> -Define a separate worker per lb and per Tomcat instance with an arbitrary worker name and -set the jvm_route attribute of the worker equal to the jvmRoute of the target Tomcat instance. -</p> -<p> -If this attribute is left empty, the name of the worker will be used. -</p> -<p> -This attribute can be changed at runtime using status worker. -</p> -<p> -This feature has been added in <b>jk 1.2.16</b>. -</p> -</td></tr></table> -</blockquote></td></tr></table> - -</blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr noshade size="1"></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font color="#525D76" size="-1"><em> - Copyright © 1999-2011, Apache Software Foundation - </em></font></div></td></tr></table></body></html>
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