connectors/jk/xdocs/generic_howto/workers.xml - tomcat55 - Git at Google

 <?xml version="1.0" encoding="ISO-8859-1"?>
 <!DOCTYPE document [
   <!ENTITY project SYSTEM "project.xml">
 ]>
 <document url="workers.html">

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 </copyright>
 <properties>
 <title>Workers HowTo</title>
 <author email="hgomez@apache.org">Henri Gomez</author>
 <author email="shachor@il.ibm.com">Gal Shachor</author>
 <author email="mturk@apache.org">Mladen Tur</author>
 <date>$Date$</date>
 </properties>
 <body>
 <section name="Introduction">
 <p>
 A Tomcat worker is a Tomcat instance that is waiting to execute servlets 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...
 Tomcat workers are defined in a properties file dubbed workers.properties and this tutorial
 explains how to work with it.
 </p>

 <p>
 This document was originally part of <b>Tomcat: A Minimalistic User's Guide</b> written by Gal Shachor,
 but has been split off for organizational reasons.
 </p>
 </section>

 <section name="Defining Workers">
 <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>

 <p>
 the file contains entries of the following form:
 </p>

 <p>
 <b>worker.list</b>=&lt;a comma separated list of worker names&gt;
 </p>

 <source>
   # the list of workers
   worker.list= worker1, worker2
 </source>

 <p>
 When starting up, the web server plugin will instantiate the workers whose name appears in the
 <b>worker.list</b> property, these are also the workers to whom you can map requests. The directive can be used multiple times.
 </p>

 <subsection name="Workers Type">
 <p>
 Each named worker should also have a few entries to provide additional information on his behalf.
 This information includes the worker's type and other related worker information.
 Currently the following worker types that exists are (JK 1.2.5):
 </p>

 <table>
   <tr><th>Type</th><th>Description</th></tr>
   <tr><td>ajp12</td><td>This worker knows how to forward requests to out-of-process Tomcat workers using the ajpv12 protocol.</td></tr>
   <tr><td>ajp13</td><td>This worker knows how to forward requests to out-of-process Tomcat workers using the ajpv13 protocol.</td></tr>
   <tr><td>jni</td><td>This worker knows how to forward requests to in-process Tomcat workers using JNI.</td></tr>
   <tr><td>lb</td><td>This is a load-balancing worker; it knows how to provide round-robin based sticky load balancing with a certain level of fault-tolerance.</td></tr>
   <tr><td>status</td><td>This is a status worker for managing load balancers.</td></tr>
 </table>

 <p>
 Defining workers of a certain type should be done with the following property format:
 </p>

 <p>
 <b>worker</b>.<b>worker name</b>.<b>type</b>=&lt;worker type&gt;
 Where worker name is the name assigned to the worker and the worker type is one of the four types defined
 in the table (a worker name may only contain any space the characters [a-zA-Z0-9\-_]).
 </p>

 <source>
   # Defines a worker named "local" that uses the ajpv12 protocol to forward requests to a Tomcat process.
   worker.local.type=ajp12
   # Defines a worker named "remote" that uses the ajpv13 protocol to forward requests to a Tomcat process.
   worker.remote.type=ajp13
   # Defines a worker named "fast" that uses JNI to forward requests to a Tomcat process.
   worker.fast.type=jni
   # Defines a worker named "loadbalancer" that loadbalances several Tomcat processes transparently.
   worker.loadbalancer.type=lb
 </source>

 </subsection>

 </section>

 <section name="Setting Worker Properties">
 <p>
 After defining the workers you can also specify properties for them.
 Properties can be specified in the following manner:
 </p>

 <p>
 worker.&lt;worker name&gt;.&lt;property&gt;=&lt;property value&gt;
 </p>

 Each worker has a set of properties that you can set as specified in the following subsections:

 <subsection name="ajp12 Worker properties">
 <p><warn>
 The <b>ajp12</b> has been <b>deprecated</b> with Tomcat 3.3.x and you should use instead
 <b>ajp13</b> which is the only ajp protocol known by Tomcat 4.x and 5 and 5.5 and Tomcat 6.
 </warn></p>
 <p>
 The ajp12 typed workers forward requests to out-of-process Tomcat workers
 using the ajpv12 protocol over TCP/IP sockets.
 </p>

 <p>
 the ajp12 worker properties are :
 </p>

 <p>
 <b>host</b> property sets the host where the Tomcat worker is listening for ajp12 requests.
 </p>

 <p>
 <b>port</b> property sets the port where the Tomcat worker is listening for ajp12 requests
 </p>

 <p>
 <b>lbfactor</b>property is used when working with a load balancer worker, this is the load-balancing factor for the worker.
 We'll see more on this in the <a href="../generic_howto/loadbalancers.html">lb worker</a> section.
 </p>

 <source>
   # worker "worker1" will talk to Tomcat listening on machine www.x.com at port 8007 using 2 lb factor
   worker.worker1.host=www.x.com
   worker.worker1.port=8007
   worker.worker1.lbfactor=2
 </source>

 <p>
 Notes: In the ajpv12 protocol, connections are created, used and then closed at each request.
 The default port for ajp12 is 8007
 </p>

 </subsection>

 <subsection name="ajp13 Worker properties">
 <p>
 The ajp13 typed workers forward requests to out-of-process Tomcat workers using the ajpv13 protocol over TCP/IP sockets.
 The main difference between ajpv12 and ajpv13 are that:
 <ul>
 <li>
 ajpv13 is a more binary protocol and it tries to compress some of the request data by coding
 frequently used strings as small integers.
 </li>
 <li>
 ajpv13 reuses open sockets and leaves them open for future requests (remember when you've got a Firewall between your
 web server and Tomcat).
 </li>
 <li>
 ajpv13 has special treatment for SSL information so that the container can implement
 SSL related methods such as isSecure().
 </li>
 </ul>

 </p>

 <p>
 You should note that Ajp13 is now the only out-process protocol supported by Tomcat 4.0.x, 4.1.x, 5.0.x, 5.5.x and 6.
 </p>


 <source>
   # worker "worker2" will talk to Tomcat listening on machine www2.x.com at port 8009 using 3 lb factor
   worker.worker2.host=www2.x.com
   worker.worker2.port=8009
   worker.worker2.lbfactor=3
   # worker "worker2" uses connections, which will stay no more than 10mn in the connection pool
   worker.worker2.connection_pool_timeout=600
   # worker "worker2" ask operating system to send KEEP-ALIVE signal on the connection
   worker.worker2.socket_keepalive=1
   # mount can be used as an alternative to the JkMount directive
   worker.worker2.mount=/contexta /contexta/* /contextb /contextb/*
 </source>

 <p>
 Notes: In the ajpv13 protocol, the default port is 8009
 </p>

 </subsection>

 <subsection name="lb Worker properties">
 <p>
 The load-balancing worker does not really communicate with Tomcat workers.
 Instead it is responsible for the management of several "real" workers.
 This 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 falling-back 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.
 The following table specifies some properties that the lb worker can accept:
 <ul>
 <li><b>balance_workers</b> is a comma separated list of workers that the load balancer need to manage.
 These workers should not appear in the worker.list property. This directive can be used multiple times for the same load balancer.</li>
 <li><b>sticky_session</b> specifies whether requests with SESSION ID's should be routed back to the same
 Tomcat worker. Set sticky_session to False when Tomcat is using a Session Manager which
 can persist session data across multiple instances of Tomcat. By default sticky_session is set to True.</li>
 </ul>
 </p>

 <source>
   # The worker balance1 while use "real" workers worker1 and worker2
   worker.balance1.balance_workers=worker1, worker2
 </source>

 </subsection>

 <subsection name="Status Worker properties">
 <p>
 The status worker does not communicate with Tomcat.
 Instead it is responsible for the load balancer management.
 </p>
 <source>
   # Add the status worker to the worker list
   worker.list=jkstatus
   # Define a 'jkstatus' worker using status
   worker.jkstatus.type=status
 </source>
 <p>Next thing is to mount the requests to the jkstatus worker. For Apache
 web servers use the:</p>
 <source>
   # Add the jkstatus mount point
   JkMount /jkmanager/* jkstatus
 </source>
 <p>To obtain a higher level of security use the:</p>
 <source>
   # Enable the JK manager access from localhost only
  &lt;Location /jkmanager/&gt;
     JkMount jkstatus
     Order deny,allow
     Deny from all
     Allow from 127.0.0.1
  &lt;/Location&gt;
 </source>

 </subsection>

 <subsection name="Property file macros">
 <p>
 You can define "macros" in the property files.
 These macros let you define properties and later on use them while
 constructing other properties and it's very usefull when you want to
 change your Java Home, Tomcat Home or OS path separator
 </p>

 <source>
   # property example, don't hardcode path separator
   ps=\
   workers.tomcat_home=d:\tomcat
   workers.java_home=d:\sdk\jdk1.2.2
   # Using macros we'll have : worker.inprocess.class_path=d:\tomcat\classes
   worker.inprocess.class_path=$(workers.tomcat_home)$(ps)classes
   # Using macros we'll have : worker.inprocess.class_path=d:\sdk\jdk1.2.2\lib\tools.jar
   worker.inprocess.class_path=$(workers.java_home)$(ps)lib$(ps)tools.jar
 </source>

 </subsection>

 <subsection name="Hierarchical property configuration">
 <p>
 Workers can reference configurations of other workers.
 If worker "x" references worker "y", then it inherits all
 configuration parameters from "y", except for the ones
 that have explicitely been set for "x".
 </p>

 <source>
   # worker toe defines some default settings
   worker.toe.type=ajp13
   worker.toe.socket_keepalive=true
   worker.toe.connect_timeout=10000
   worker.toe.recovery_options=7
   # workers tic and tac inherit those values
   worker.tic.reference=worker.toe
   worker.tac.reference=worker.toe
 </source>

 <p>
 Please note, that the reference contains
 the full prefix to the referenced configuration attributes,
 not only the name of the referenced worker.
 </p>

 <p>
 References can be nested. Be careful to avoid loops!
 </p>

 <p>
 References are especially useful, when configuring load balancers.
 Try to understand the following two stage references:
 </p>

 <source>
   # We only use one load balancer
   worker.list=lb
   # Let's define some defaults
   worker.basic.port=8009
   worker.basic.type=ajp13
   worker.basic.socket_keepalive=true
   worker.basic.connect_timeout=10000
   worker.basic.recovery_options=7
   # And we use them in two groups
   worker.lb1.domain=dom1
   worker.lb1.distance=0
   worker.lb1.reference=worker.basic
   worker.lb2.domain=dom2
   worker.lb2.distance=1
   worker.lb2.reference=worker.basic
   # Now we configure the load balancer
   worker.lb.type=lb
   worker.lb.method=B
   worker.lb.balanced_workers=w11,w12,w21,w22
   worker.w11.host=myhost11
   worker.w11.reference=worker.lb1
   worker.w12.host=myhost12
   worker.w12.reference=worker.lb1
   worker.w21.host=myhost21
   worker.w21.reference=worker.lb2
   worker.w22.host=myhost22
   worker.w22.reference=worker.lb2
 </source>

 </subsection>

 </section>

 <section name="A sample worker.properties">
 <p>
 Since coping with worker.properties on your own is not an easy thing to do,
 a sample worker.properties file is bundled along JK.
 </p>

 <p>
 You could also find here a sample workers.properties defining :
 </p>

 <ul>
 <li>
 An ajp12 worker that used the host localhost and the port 8007
 </li>
 <li>
 An ajp13 worker that used the host localhost and the port 8008
 </li>
 <li>
 A jni worker
 </li>
 <li>
 A lb worker that load balance the ajp12 and ajp13 workers
 </li>
 </ul>

 <source>
   # Define some properties
   workers.apache_log=/var/log/httpd/
   workers.tomcat_home=/var/tomcat3
   workers.java_home=/opt/IBMJava2-131/
   ps=/
   # Define 4 workers, 3 real workers using ajp12, ajp13, jni, the last one being a loadbalancing worker
   worker.list=worker1, worker2, worker3, worker4
   # Set properties for worker1 (ajp12)
   worker.worker1.type=ajp12
   worker.worker1.host=locahost
   worker.worker1.port=8007
   worker.worker1.lbfactor=1
   # Set properties for worker2 (ajp13)
   worker.worker2.type=ajp13
   worker.worker2.host=locahost
   worker.worker2.port=8009
   worker.worker2.lbfactor=1
   worker.worker2.connection_pool_timeout=600
   worker.worker2.socket_keepalive=1
   worker.worker2.socket_timeout=60
   # Set properties for worker3 (jni)
   worker.worker3.type=jni
   # Set worker3 bridge type, here Tomcat 3.3
   worker.worker3.bridge=tomcat33
   # Set worker3 classpath
   worker.worker3.class_path=$(workers.tomcat_home)$(ps)classes
   worker.worker3.class_path=$(workers.tomcat_home)$(ps)lib$(ps)tomcat.jar
   # Set worker3 tomcat command line
   worker.worker3.cmd_line=-home
   worker.worker3.cmd_line=$(workers.tomcat_home)
   # Set worker3 Tomcat/JVM settings
   worker.worker3.jvm_lib=$(workers.java_home)$(ps)jre$(ps)bin$(ps)classic$(ps)libjvm.so
   worker.worker3.stdout=$(workers.apache_log)$(ps)inprocess.stdout
   worker.worker3.stderr=$(workers.apache_log)$(ps)inprocess.stderr
   worker.worker3.sysprops=tomcat.home=$(workers.tomcat_home)
   # Set properties for worker4 (lb) which use worker1 and worker2
   worker.worker4.balance_workers=worker1,worker2
 </source>

 </section>
 </body>
 </document>
	<?xml version="1.0" encoding="ISO-8859-1"?>
	<!DOCTYPE document [
	<!ENTITY project SYSTEM "project.xml">
	]>
	<document url="workers.html">

	&project;
	<copyright>
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file distributed with
	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	</copyright>
	<properties>
	<title>Workers HowTo</title>
	<author email="hgomez@apache.org">Henri Gomez</author>
	<author email="shachor@il.ibm.com">Gal Shachor</author>
	<author email="mturk@apache.org">Mladen Tur</author>
	<date>$Date$</date>
	</properties>
	<body>
	<section name="Introduction">
	<p>
	A Tomcat worker is a Tomcat instance that is waiting to execute servlets 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...
	Tomcat workers are defined in a properties file dubbed workers.properties and this tutorial
	explains how to work with it.
	</p>

	<p>
	This document was originally part of <b>Tomcat: A Minimalistic User's Guide</b> written by Gal Shachor,
	but has been split off for organizational reasons.
	</p>
	</section>

	<section name="Defining Workers">
	<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>

	<p>
	the file contains entries of the following form:
	</p>

	<p>
	<b>worker.list</b>=<a comma separated list of worker names>
	</p>

	<source>
	# the list of workers
	worker.list= worker1, worker2
	</source>

	<p>
	When starting up, the web server plugin will instantiate the workers whose name appears in the
	<b>worker.list</b> property, these are also the workers to whom you can map requests. The directive can be used multiple times.
	</p>

	<subsection name="Workers Type">
	<p>
	Each named worker should also have a few entries to provide additional information on his behalf.
	This information includes the worker's type and other related worker information.
	Currently the following worker types that exists are (JK 1.2.5):
	</p>

	<table>
	<tr><th>Type</th><th>Description</th></tr>
	<tr><td>ajp12</td><td>This worker knows how to forward requests to out-of-process Tomcat workers using the ajpv12 protocol.</td></tr>
	<tr><td>ajp13</td><td>This worker knows how to forward requests to out-of-process Tomcat workers using the ajpv13 protocol.</td></tr>
	<tr><td>jni</td><td>This worker knows how to forward requests to in-process Tomcat workers using JNI.</td></tr>
	<tr><td>lb</td><td>This is a load-balancing worker; it knows how to provide round-robin based sticky load balancing with a certain level of fault-tolerance.</td></tr>
	<tr><td>status</td><td>This is a status worker for managing load balancers.</td></tr>
	</table>

	<p>
	Defining workers of a certain type should be done with the following property format:
	</p>

	<p>
	<b>worker</b>.<b>worker name</b>.<b>type</b>=<worker type>
	Where worker name is the name assigned to the worker and the worker type is one of the four types defined
	in the table (a worker name may only contain any space the characters [a-zA-Z0-9\-_]).
	</p>

	<source>
	# Defines a worker named "local" that uses the ajpv12 protocol to forward requests to a Tomcat process.
	worker.local.type=ajp12
	# Defines a worker named "remote" that uses the ajpv13 protocol to forward requests to a Tomcat process.
	worker.remote.type=ajp13
	# Defines a worker named "fast" that uses JNI to forward requests to a Tomcat process.
	worker.fast.type=jni
	# Defines a worker named "loadbalancer" that loadbalances several Tomcat processes transparently.
	worker.loadbalancer.type=lb
	</source>

	</subsection>

	</section>

	<section name="Setting Worker Properties">
	<p>
	After defining the workers you can also specify properties for them.
	Properties can be specified in the following manner:
	</p>

	<p>
	worker.<worker name>.<property>=<property value>
	</p>

	Each worker has a set of properties that you can set as specified in the following subsections:

	<subsection name="ajp12 Worker properties">
	<p><warn>
	The <b>ajp12</b> has been <b>deprecated</b> with Tomcat 3.3.x and you should use instead
	<b>ajp13</b> which is the only ajp protocol known by Tomcat 4.x and 5 and 5.5 and Tomcat 6.
	</warn></p>
	<p>
	The ajp12 typed workers forward requests to out-of-process Tomcat workers
	using the ajpv12 protocol over TCP/IP sockets.
	</p>

	<p>
	the ajp12 worker properties are :
	</p>

	<p>
	<b>host</b> property sets the host where the Tomcat worker is listening for ajp12 requests.
	</p>

	<p>
	<b>port</b> property sets the port where the Tomcat worker is listening for ajp12 requests
	</p>

	<p>
	<b>lbfactor</b>property is used when working with a load balancer worker, this is the load-balancing factor for the worker.
	We'll see more on this in the <a href="../generic_howto/loadbalancers.html">lb worker</a> section.
	</p>

	<source>
	# worker "worker1" will talk to Tomcat listening on machine www.x.com at port 8007 using 2 lb factor
	worker.worker1.host=www.x.com
	worker.worker1.port=8007
	worker.worker1.lbfactor=2
	</source>

	<p>
	Notes: In the ajpv12 protocol, connections are created, used and then closed at each request.
	The default port for ajp12 is 8007
	</p>

	</subsection>

	<subsection name="ajp13 Worker properties">
	<p>
	The ajp13 typed workers forward requests to out-of-process Tomcat workers using the ajpv13 protocol over TCP/IP sockets.
	The main difference between ajpv12 and ajpv13 are that:
	<ul>
	<li>
	ajpv13 is a more binary protocol and it tries to compress some of the request data by coding
	frequently used strings as small integers.
	</li>
	<li>
	ajpv13 reuses open sockets and leaves them open for future requests (remember when you've got a Firewall between your
	web server and Tomcat).
	</li>
	<li>
	ajpv13 has special treatment for SSL information so that the container can implement
	SSL related methods such as isSecure().
	</li>
	</ul>

	</p>

	<p>
	You should note that Ajp13 is now the only out-process protocol supported by Tomcat 4.0.x, 4.1.x, 5.0.x, 5.5.x and 6.
	</p>


	<source>
	# worker "worker2" will talk to Tomcat listening on machine www2.x.com at port 8009 using 3 lb factor
	worker.worker2.host=www2.x.com
	worker.worker2.port=8009
	worker.worker2.lbfactor=3
	# worker "worker2" uses connections, which will stay no more than 10mn in the connection pool
	worker.worker2.connection_pool_timeout=600
	# worker "worker2" ask operating system to send KEEP-ALIVE signal on the connection
	worker.worker2.socket_keepalive=1
	# mount can be used as an alternative to the JkMount directive
	worker.worker2.mount=/contexta /contexta/* /contextb /contextb/*
	</source>

	<p>
	Notes: In the ajpv13 protocol, the default port is 8009
	</p>

	</subsection>

	<subsection name="lb Worker properties">
	<p>
	The load-balancing worker does not really communicate with Tomcat workers.
	Instead it is responsible for the management of several "real" workers.
	This 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 falling-back 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.
	The following table specifies some properties that the lb worker can accept:
	<ul>
	<li><b>balance_workers</b> is a comma separated list of workers that the load balancer need to manage.
	These workers should not appear in the worker.list property. This directive can be used multiple times for the same load balancer.</li>
	<li><b>sticky_session</b> specifies whether requests with SESSION ID's should be routed back to the same
	Tomcat worker. Set sticky_session to False when Tomcat is using a Session Manager which
	can persist session data across multiple instances of Tomcat. By default sticky_session is set to True.</li>
	</ul>
	</p>

	<source>
	# The worker balance1 while use "real" workers worker1 and worker2
	worker.balance1.balance_workers=worker1, worker2
	</source>

	</subsection>

	<subsection name="Status Worker properties">
	<p>
	The status worker does not communicate with Tomcat.
	Instead it is responsible for the load balancer management.
	</p>
	<source>
	# Add the status worker to the worker list
	worker.list=jkstatus
	# Define a 'jkstatus' worker using status
	worker.jkstatus.type=status
	</source>
	<p>Next thing is to mount the requests to the jkstatus worker. For Apache
	web servers use the:</p>
	<source>
	# Add the jkstatus mount point
	JkMount /jkmanager/* jkstatus
	</source>
	<p>To obtain a higher level of security use the:</p>
	<source>
	# Enable the JK manager access from localhost only
	<Location /jkmanager/>
	JkMount jkstatus
	Order deny,allow
	Deny from all
	Allow from 127.0.0.1
	</Location>
	</source>

	</subsection>

	<subsection name="Property file macros">
	<p>
	You can define "macros" in the property files.
	These macros let you define properties and later on use them while
	constructing other properties and it's very usefull when you want to
	change your Java Home, Tomcat Home or OS path separator
	</p>

	<source>
	# property example, don't hardcode path separator
	ps=\
	workers.tomcat_home=d:\tomcat
	workers.java_home=d:\sdk\jdk1.2.2
	# Using macros we'll have : worker.inprocess.class_path=d:\tomcat\classes
	worker.inprocess.class_path=$(workers.tomcat_home)$(ps)classes
	# Using macros we'll have : worker.inprocess.class_path=d:\sdk\jdk1.2.2\lib\tools.jar
	worker.inprocess.class_path=$(workers.java_home)$(ps)lib$(ps)tools.jar
	</source>

	</subsection>

	<subsection name="Hierarchical property configuration">
	<p>
	Workers can reference configurations of other workers.
	If worker "x" references worker "y", then it inherits all
	configuration parameters from "y", except for the ones
	that have explicitely been set for "x".
	</p>

	<source>
	# worker toe defines some default settings
	worker.toe.type=ajp13
	worker.toe.socket_keepalive=true
	worker.toe.connect_timeout=10000
	worker.toe.recovery_options=7
	# workers tic and tac inherit those values
	worker.tic.reference=worker.toe
	worker.tac.reference=worker.toe
	</source>

	<p>
	Please note, that the reference contains
	the full prefix to the referenced configuration attributes,
	not only the name of the referenced worker.
	</p>

	<p>
	References can be nested. Be careful to avoid loops!
	</p>

	<p>
	References are especially useful, when configuring load balancers.
	Try to understand the following two stage references:
	</p>

	<source>
	# We only use one load balancer
	worker.list=lb
	# Let's define some defaults
	worker.basic.port=8009
	worker.basic.type=ajp13
	worker.basic.socket_keepalive=true
	worker.basic.connect_timeout=10000
	worker.basic.recovery_options=7
	# And we use them in two groups
	worker.lb1.domain=dom1
	worker.lb1.distance=0
	worker.lb1.reference=worker.basic
	worker.lb2.domain=dom2
	worker.lb2.distance=1
	worker.lb2.reference=worker.basic
	# Now we configure the load balancer
	worker.lb.type=lb
	worker.lb.method=B
	worker.lb.balanced_workers=w11,w12,w21,w22
	worker.w11.host=myhost11
	worker.w11.reference=worker.lb1
	worker.w12.host=myhost12
	worker.w12.reference=worker.lb1
	worker.w21.host=myhost21
	worker.w21.reference=worker.lb2
	worker.w22.host=myhost22
	worker.w22.reference=worker.lb2
	</source>

	</subsection>

	</section>

	<section name="A sample worker.properties">
	<p>
	Since coping with worker.properties on your own is not an easy thing to do,
	a sample worker.properties file is bundled along JK.
	</p>

	<p>
	You could also find here a sample workers.properties defining :
	</p>

	<ul>
	<li>
	An ajp12 worker that used the host localhost and the port 8007
	</li>
	<li>
	An ajp13 worker that used the host localhost and the port 8008
	</li>
	<li>
	A jni worker
	</li>
	<li>
	A lb worker that load balance the ajp12 and ajp13 workers
	</li>
	</ul>

	<source>
	# Define some properties
	workers.apache_log=/var/log/httpd/
	workers.tomcat_home=/var/tomcat3
	workers.java_home=/opt/IBMJava2-131/
	ps=/
	# Define 4 workers, 3 real workers using ajp12, ajp13, jni, the last one being a loadbalancing worker
	worker.list=worker1, worker2, worker3, worker4
	# Set properties for worker1 (ajp12)
	worker.worker1.type=ajp12
	worker.worker1.host=locahost
	worker.worker1.port=8007
	worker.worker1.lbfactor=1
	# Set properties for worker2 (ajp13)
	worker.worker2.type=ajp13
	worker.worker2.host=locahost
	worker.worker2.port=8009
	worker.worker2.lbfactor=1
	worker.worker2.connection_pool_timeout=600
	worker.worker2.socket_keepalive=1
	worker.worker2.socket_timeout=60
	# Set properties for worker3 (jni)
	worker.worker3.type=jni
	# Set worker3 bridge type, here Tomcat 3.3
	worker.worker3.bridge=tomcat33
	# Set worker3 classpath
	worker.worker3.class_path=$(workers.tomcat_home)$(ps)classes
	worker.worker3.class_path=$(workers.tomcat_home)$(ps)lib$(ps)tomcat.jar
	# Set worker3 tomcat command line
	worker.worker3.cmd_line=-home
	worker.worker3.cmd_line=$(workers.tomcat_home)
	# Set worker3 Tomcat/JVM settings
	worker.worker3.jvm_lib=$(workers.java_home)$(ps)jre$(ps)bin$(ps)classic$(ps)libjvm.so
	worker.worker3.stdout=$(workers.apache_log)$(ps)inprocess.stdout
	worker.worker3.stderr=$(workers.apache_log)$(ps)inprocess.stderr
	worker.worker3.sysprops=tomcat.home=$(workers.tomcat_home)
	# Set properties for worker4 (lb) which use worker1 and worker2
	worker.worker4.balance_workers=worker1,worker2
	</source>

	</section>
	</body>
	</document>