connectors/jk/xdocs/reference/apache.xml - tomcat55 - Git at Google

 <?xml version="1.0"?>
 <!DOCTYPE document [
   <!ENTITY project SYSTEM "project.xml">
 ]>
 <document url="apache.html">

     &project;

     <properties>
         <author email="mturk@apache.org">Mladen Turk</author>
         <title>Configuring Apache</title>
     </properties>

 <body>

 <section name="Configuration Directives">
 <p>
 Most of the directives are allowed once in the global part of the Apache httpd
 configuration and once in every &lt;VirtualHost&gt; elements. Exceptions from this rule are
 explicitely listed in the table below.
 </p>
 <p>
 Values are inherited from the main server to the virtual hosts.
 Since version 1.2.20 they can be overwritten in the virtual hosts.
 Exceptions from this rule are
 again explicitely listed in the table below.
 </p>
 <p><b>Waring: If Apache httpd and Tomcat are configured to serve content from
 the same filing system location then care must be taken to ensure that httpd is
 not able to serve inappropriate content such as the contents of the WEB-INF
 directory or JSP source code.</b> This could occur if the httpd DocumentRoot
 overlaps with a Tomcat Host's appBase or the docBase of any Context. It could
 also occur when using the httpd Alias directive with a Tomcat Host's appBase or
 the docBase of any Context.
 </p>
 <p>
 Here are the all directives supported by Apache:
 </p>
 <attributes name="Directive">
 <attribute name="JkWorkersFile" required="false"><p>
 The name of a worker file for the Tomcat servlet containers.
 <br/>
 This directive is only allowed once. It must be put into
  the global part of the configuration.
 <br/>
 If you don't use the JkWorkerProperty directives, then you must
 define your workers with a valid JkWorkersFile. There is no default
 value.
 </p></attribute>
 <attribute name="JkWorkerProperty" required="false"><p>
 Enables setting worker properties inside Apache configuration file.
 The syntax is the same as in the JkWorkersFile (usually workers.properties).
 Simply prefix each line with "JkWorkerProperty" to put it directly into
 the Apache httpd config files.
 <br/>
 This directive is allowed multiple times.
 It must be put into the global part of the configuration.
 <br/>
 If you don't use the JkWorkerProperty directives, then you must
 define your workers with a valid JkWorkersFile. There is no default
 value.
 <br/>
 This directive is available in jk1.2.7 version and later.
 </p></attribute>
 <attribute name="JkShmFile" required="false"><p>
 Shared memory file name. Used only on unix platforms.
 <br/>
 This directive is only allowed once. It must be put into
  the global part of the configuration.
 <br/>
 The default value is logs/jk-runtime-status.
 </p></attribute>
 <attribute name="JkShmSize" required="false"><p>
 Size of the shared memory file name.
 <br/>
 This directive is only allowed once. It must be put into
  the global part of the configuration.
 <br/>
 The default value depends on the platform. It is usually less than 64KB.
 </p></attribute>
 <attribute name="JkMountFile" required="false"><p>
 File containing multiple mappings from a context to a Tomcat worker.
 It is usually called uriworkermap.properties.
 <br/>
 For inheritance rules, see: JkMountCopy.
 <br/>
 There is no default value.
 </p></attribute>
 <attribute name="JkMountFileReload" required="false"><p>
 This directive configures the reload check interval in seconds.
 The JkMountFile is checked periodically for changes.
 A changed file gets reloaded automatically. If you set
 this directive to "0", reload checking is turned off.
 <br/>
 The default value is 60 seconds.
 <br/>
 This directive has been added in version 1.2.20 of mod_jk.
 </p></attribute>
 <attribute name="JkMount" required="false"><p>
 A mount point from a context to a Tomcat worker.
 <br/>
 This directive is allowed multiple times.
 It is allowed in the global configuration and in VirtualHost.
 You can also use it inside Location with a different syntax.
 Inside Location, one omits the first argument (path),
 which gets inherited from the Location.
 For inheritance rules, see: JkMountCopy.
 </p></attribute>
 <attribute name="JkUnMount" required="false"><p>
 An exclusion mount point from a context to a Tomcat worker.
 All exclusion mounts are checked after mapping a request
 to a tomcat worker. If the request maps also to an exclusion,
 it will not be forwarded to tomcat, and instead be served locally.
 <br/>
 This directive is allowed multiple times.
 It is allowed in the global configuration and in VirtualHost.
 You can also use it inside Location with a different syntax.
 Inside Location, one omits the first argument (path),
 which gets inherited from the Location.
 For inheritance rules, see: JkMountCopy.
 <br/>
 This directive is available in jk1.2.7 version and later.
 </p></attribute>
 <attribute name="JkAutoAlias" required="false"><p>
 Automatically Alias webapp context directories into the Apache
 document space.
 <br/>
 Care should be taken to ensure that only static content is served via httpd as a
 result of using this directive. Any static content served by httpd will bypass any
 security constraints defined in the application's web.xml.
 <br/>
 For inheritance rules, see: JkMountCopy.
 <br/>
 There is no default value.
 </p></attribute>
 <attribute name="JkMountCopy" required="false"><p>
 If this directive is set to On in some virtual server,
 the mounts from the global server will be copied to the
 virtual server, more precisely all mounts defined by JkMount
 or JkUnMount. The Mounts defined by JkMountFile and JkAutoAlias
 will only be inherited, if the VirtualHost does not define
 it's own JkMountFile or JkAutoAlias.
 <br/>
 This directive is only allowed inside VirtualHost.
 <br/>
 The default is Off.
 </p></attribute>
 <attribute name="JkWorkerIndicator" required="false"><p>
 Name of the Apache environment variable that can be used to set worker names
 in combination with SetHandler jakarta-servlet.
 <br/>
 This directive is only allowed once per virtual server.
 It is allowed in the global configuration and in VirtualHost.
 <br/>
 The default value is JK_WORKER_NAME.
 </p></attribute>
 <attribute name="JkLogFile" required="false"><p>
 Full or server relative path to the Tomcat Connector module log file.
 It will also work with pipe, by using a value of the form "| ...".
 <br/>
 The default value is logs/mod_jk.log.
 <br/>
 Pipes are supported for Apache 1.3 only since version 1.2.16.
 The default value exists only since version 1.2.20.
 </p></attribute>
 <attribute name="JkLogLevel" required="false"><p>
 The Tomcat Connector module log level, can be debug, info, warn
 error or trace.
 <br/>
 The default value is info.
 </p></attribute>
 <attribute name="JkLogStampFormat" required="false"><p>
 The Tomcat Connector module <b>date</b> log format, follow strftime syntax.
 This format will be used for the time stamps in the JkLogFile.
 <br/>
 The default value is "[%a %b %d %H:%M:%S %Y] ".
 </p></attribute>
 <attribute name="JkRequestLogFormat" required="false"><p>
 Request log format string. See detailed description below.
 <br/>
 There is no default value. Without defining a value, the request logging
 is turned off.
 </p></attribute>
 <attribute name="JkExtractSSL" required="false"><p>
 Turns on SSL processing and information gathering by mod_jk
 <br/>
 The default value is On.
 </p></attribute>
 <attribute name="JkHTTPSIndicator" required="false"><p>
 Name of the Apache environment variable that contains SSL indication.
 <br/>
 The default value is "HTTPS".
 </p></attribute>
 <attribute name="JkCERTSIndicator" required="false"><p>
 Name of the Apache environment variable that contains SSL client certificates.
 <br/>
 The default value is "SSL_CLIENT_CERT".
 </p></attribute>
 <attribute name="JkCIPHERIndicator" required="false"><p>
 Name of the Apache environment variable that contains SSL client cipher.
 <br/>
 The default value is "SSL_CIPHER".
 </p></attribute>
 <attribute name="JkCERTCHAINPrefix" required="false"><p>
 Name of the Apache environment (prefix) that contains SSL client chain certificates.
 <br/>
 The default value is "SSL_CLIENT_CERT_CHAIN_".
 </p></attribute>
 <attribute name="JkSESSIONIndicator" required="false"><p>
 Name of the Apache environment variable that contains SSL session.
 <br/>
 The default value is "SSL_SESSION_ID".
 </p></attribute>
 <attribute name="JkKEYSIZEIndicator" required="false"><p>
 Name of the Apache environment variable that contains SSL key size in use.
 <br/>
 The default value is "SSL_CIPHER_USEKEYSIZE".
 </p></attribute>
 <attribute name="JkOptions" required="false"><p>
 Set one of more options to configure the mod_jk module. See below for
 details about this directive.
 <br/>
 This directive can be used multiple times per virtual server.
 <br/>
 The default value is "ForwardURICompatUnparsed" since version 1.2.23.
 Until version 1.2.22 the default value was "ForwardURICompat".
 </p></attribute>
 <attribute name="JkEnvVar" required="false"><p>
 Adds a name and an optional default value of environment variable
 that should be sent to servlet-engine as a request attribute.
 If the default value is not given explicitely, the variable
 will only be send, if it is set during runtime.
 <br/>
 This directive can be used multiple times per virtual server.
 <br/>
 The default is empty, so no additional variables will be sent.
 <br/>
 Empty default values are supported since version 1.2.20.
 Not sending variables with empty defaults and empty runtime value
 has been introduced in version 1.2.21.
 </p></attribute>
 <attribute name="JkStripSession" required="false"><p>
 If this directive is set to On in some virtual server,
 the session IDs <code>;jsessionid=...</code> will be
 removed for non matched URLs.
 <br/>
 This directive is only allowed inside VirtualHost.
 <br/>
 The default is Off.
 <br/>
 This directive has been introduced in version 1.2.21.
 </p></attribute>

 </attributes>
 </section>

 <section name="Configuration Directives Types">
 <p>
 We'll discuss here the mod_jk directive types.
 </p>

 <subsection name="Define workers">
 <p>
 <b>JkWorkersFile</b> specify the location where mod_jk will find the workers definitions.
 Take a look at <a href="workers.html">Workers documentation</a> for detailed description.

 <source>

   JkWorkersFile     /etc/httpd/conf/workers.properties
 </source>

 <br/>
 <br/>
 </p>

 </subsection>

 <subsection name="Logging">
 <p>
 <b>JkLogFile</b> specify the location where mod_jk is going to place its log file.
 </p>

 <source>
   JkLogFile     /var/log/httpd/mod_jk.log
 </source>

 <p>
 Since JK 1.2.3 for Apache 2.0 and JK 1.2.16 for Apache 1.3 this can also
 be used for piped logging:
 </p>

 <source>
   JkLogFile     "|/usr/bin/rotatelogs /var/log/httpd/mod_jk.log 86400"
 </source>

 <p>
 <b>JkLogLevel</b>
 set the log level between :
 </p>

 <ul>
 <li>
 <b>info</b> log will contain standard mod_jk activity (default).
 </li>
 <li>
 <b>warn</b> log will contain non fatal error reports.
 </li>
 <li>
 <b>error</b> log will contain also error reports.
 </li>
 <li>
 <b>debug</b> log will contain all information on mod_jk activity
 </li>
 <li>
 <b>trace</b> log will contain all tracing information on mod_jk activity
 </li>
 </ul>

 <source>
   JkLogLevel    info
 </source>

 <p>
 <code>info</code> should be your default selection for normal operations.
 <br/>
 <br/>
 </p>

 <p>
 <b>JkLogStampFormat</b> will configure the date/time format found on mod_jk log file.
 Using the strftime() format string it's set by<br />
 default to <b>"[%a %b %d %H:%M:%S %Y]"</b>
 </p>

 <source>
   JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
 </source>

 <p>
 <br/>
 <br/>
 </p>

 <p>
 <b>JkRequestLogFormat</b> will configure the format of mod_jk individual request logging.
 Request logging is configured and enabled on a per virtual host basis.
 To enable request logging for a virtual host just add a JkRequestLogFormat config.
 The syntax of the format string is similar to the Apache LogFormat command,
 here is a list of the available request log format options:
 </p>

 <p>
 <attributes name="Options">
   <attribute name="%b" required="false">Bytes sent, excluding HTTP headers (CLF format)</attribute>
   <attribute name="%B" required="false">Bytes sent, excluding HTTP headers</attribute>
   <attribute name="%H" required="false">The request protocol</attribute>
   <attribute name="%m" required="false">The request method</attribute>
   <attribute name="%p" required="false">The canonical Port of the server serving the request</attribute>
   <attribute name="%q" required="false">The query string (prepended with a ? if a query string exists, otherwise an empty string)</attribute>
   <attribute name="%r" required="false">First line of request</attribute>
   <attribute name="%s" required="false">Request HTTP status code</attribute>
   <attribute name="%T" required="false">Request duration, elapsed time to handle request in seconds '.' micro seconds</attribute>
   <attribute name="%U" required="false">The URL path requested, not including any query string.</attribute>
   <attribute name="%v" required="false">The canonical ServerName of the server serving the request</attribute>
   <attribute name="%V" required="false">The server name according to the UseCanonicalName setting</attribute>
   <attribute name="%w" required="false">Tomcat worker name</attribute>
   <attribute name="%R" required="false">Real worker name</attribute>
 </attributes>

 <source>
   JkRequestLogFormat     "%w %V %T"
 </source>

 <br/>
 <br/>
 </p>

 <p>
 You can also log mod_jk information using the Apache standard module <b>mod_log_config</b>.
 The module sets several notes in the Apache httpd notes table.
 Most of them are are only useful in combination with a load balancer worker.
 </p>

 <p>
 <attributes name="Note">
   <attribute name="JK_WORKER_NAME" required="false">Name of the worker selected by the URI mapping</attribute>
   <attribute name="JK_WORKER_TYPE" required="false">Type of the worker selected by the URI mapping</attribute>
   <attribute name="JK_WORKER_ROUTE" required="false">Actual worker name selected by the URI mapping (usually a member of the load balancer)</attribute>
   <attribute name="JK_REQUEST_DURATION" required="false">Request duration in seconds and microseconds.
                                                          At the moment only available if JkRequestLogFormat is set.</attribute>
   <attribute name="JK_LB_FIRST_NAME" required="false">Load-Balancer: Name of the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_TYPE" required="false">Load-Balancer: Type of the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_ACCESSED" required="false">Load-Balancer: Access count for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_READ" required="false">Load-Balancer: Bytes read for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_TRANSFERRED" required="false">Load-Balancer: Bytes transferred for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_ERRORS" required="false">Load-Balancer: Error count for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_BUSY" required="false">Load-Balancer: Busy count for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_ACTIVATION" required="false">Load-Balancer: Activation state for the first worker tried</attribute>
   <attribute name="JK_LB_FIRST_STATE" required="false">Load-Balancer: Error state for the first worker tried</attribute>
   <attribute name="JK_LB_LAST_NAME" required="false">Load-Balancer: Name of the last worker tried</attribute>
   <attribute name="JK_LB_LAST_TYPE" required="false">Load-Balancer: Type of the last worker tried</attribute>
   <attribute name="JK_LB_LAST_ACCESSED" required="false">Load-Balancer: Access count for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_READ" required="false">Load-Balancer: Bytes read for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_TRANSFERRED" required="false">Load-Balancer: Bytes transferred for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_ERRORS" required="false">Load-Balancer: Error count for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_BUSY" required="false">Load-Balancer: Busy count for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_ACTIVATION" required="false">Load-Balancer: Activation state for the last worker tried</attribute>
   <attribute name="JK_LB_LAST_STATE" required="false">Load-Balancer: Error state for the last worker tried</attribute>
 </attributes>

 <source>
   LogFormat     "%h %l %u %t \"%r\" %>s %b %{JK_WORKER_NAME}n %{JK_LB_FIRST_NAME}n \
                  %{JK_LB_FIRST_BUSY}n %{JK_LB_LAST_NAME}n %{JK_LB_LAST_BUSY}n" mod_jk_log
   CustomLog     logs/access_log     mod_jk_log
 </source>

 <br/>
 <br/>
 </p>

 </subsection>

 <subsection name="Forwarding">
 <p>
 The directive JkOptions allow you to set many forwarding options which will enable (+)
 or disable (-) following option. Without any leading signs, options will be enabled.
 <br/>
 <br/>
 </p>

 <p>
 The three following options <b>+ForwardURIxxx</b> are mutually exclusive.
 Exactly one of them is required, a negative sign prefix is not allowed with them.
 The default value is "ForwardURICompatUnparsed" since version 1.2.23.
 Until version 1.2.22 the default value was "ForwardURICompat".
 You can turn the default off by switching on one of the other two options.
 <br/>
 <br/>
 </p>

 <p>
 All options are inherited from the global server to virtual hosts.
 Options that support enabling (plus options) and disabling (minus options),
 are inherited in the following way:
 <br/>
 <br/>
 options(vhost) = plus_options(global) - minus_options(global) + plus_options(vhost) - minus_options(vhost)
 <br/>
 <br/>
 </p>

 <p>
 Using JkOptions <b>ForwardURICompatUnparsed</b>, the forwarded URI
 will be unparsed. It's spec compliant and also the safest option.
 It will always forward the original request URI, so rewriting
 URIs with mod_rewrite and then forwarding the rewritten URI
 will not work.

 <source>
   JkOptions     +ForwardURICompatUnparsed
 </source>

 <br/>
 <br/>
 </p>

 <p>
 Using JkOptions <b>ForwardURICompat</b>, the forwarded URI will
 be decoded by Apache httpd. Encoded characters will be decoded and
 explicit path components like ".." will already be resolved.
 This is less spec compliant and is <b>not safe</b> if you are using
 prefix JkMount. This option will allow to rewrite URIs with
 mod_rewrite before forwarding.

 <source>
   JkOptions     +ForwardURICompat
 </source>

 <br/>
 <br/>
 </p>

 <p>
 Using JkOptions <b>ForwardURIEscaped</b>, the forwarded URI will
 be the encoded form of the URI used by ForwardURICompat.
 Explicit path components like ".." will already be resolved.
 This will not work in combination with URL encoded session IDs,
 but it will allow to rewrite URIs with mod_rewrite before forwarding.

 <source>
   JkOptions     +ForwardURIEscaped
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>ForwardDirectories</b> is used in conjunction with <b>DirectoryIndex</b>
 directive of Apache web server. As such mod_dir should be available to Apache,
 statically or dynamically (DSO)
 <br/>
 <br/>
 </p>

 <p>
 When DirectoryIndex is configured, Apache will create sub-requests for
 each of the local-url's specified in the directive, to determine if there is a
 local file that matches (this is done by stat-ing the file).
 </p>

 <p>
 If ForwardDirectories is set to false (default) and Apache doesn't find any
 files that match, Apache will serve the content of the directory (if directive
 Options specifies Indexes for that directory) or a <code>403 Forbidden</code> response (if
 directive Options doesn't specify Indexes for that directory).
 </p>

 <p>
 If ForwarDirectories is set to true and Apache doesn't find any files that
 match, the request will be forwarded to Tomcat for resolution. This is used in
 cases when Apache cannot see the index files on the file system for various
 reasons: Tomcat is running on a different machine, the JSP file has been
 precompiled etc.
 </p>

 <p>Note that locally visible files will take precedence over the
 ones visible only to Tomcat (i.e. if Apache can see the file, that's the one
 that's going to get served). This is important if there is more then one type of
 file that Tomcat normally serves - for instance Velocity pages and JSP pages.

 <source>
   JkOptions     +ForwardDirectories
 </source>
 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>ForwardLocalAddress</b>, you ask mod_jk to send the local address,
 of the Apache web server instead remote client address. This can be used by
 Tomcat remote address valve for allowing connections only from registered Apache
 web servers.

 <source>
   JkOptions     +ForwardLocalAddress
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>FlushPackets</b>, you ask mod_jk to flush Apache's connection
 buffer after each AJP packet chunk received from Tomcat. This option can have
 a strong performance penalty for Apache and Tomcat as writes are performed
 more often than would normally be required (ie: at the end of each
 response).

 <source>
   JkOptions     +FlushPackets
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>FlushHeader</b>, you ask mod_jk to flush Apache's connection
 buffer after the response headers have been  received from Tomcat.

 <source>
   JkOptions     +FlushHeader
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>DisableReuse</b>, you ask mod_jk to close connections immediately
 after their use. Normally mod_jk uses persistent connections and pools idle
 connections to reuse them, when new requests have to be sent to Tomcat.
 </p>

 <p>
 Using this option will have a strong performance penalty for Apache and Tomcat.
 Use this only as a last resort in case of unfixable network problems.
 If a firewall between Apache and Tomcat silently kills idle connections,
 try to use the worker attribute socket_keepalive in combination with an appropriate
 TCP keepalive value in your OS.

 <source>
   JkOptions     +DisableReuse
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>ForwardKeySize</b>,  you ask mod_jk, when using ajp13, to forward also the SSL Key Size  as
 required by Servlet API 2.3.
 This flag shouldn't be set when servlet engine is Tomcat 3.2.x (on by default).

 <source>
   JkOptions     +ForwardKeySize
 </source>

 <br/>
 <br/>
 </p>

 <p>
 JkOptions <b>ForwardSSLCertChain</b>,  you ask mod_jk, when using ajp13,
 to forward SSL certificate chain (off by default).
 Mod_jk only passes the <code>SSL_CLIENT_CERT</code> to the AJP connector. This is not a
 problem with self-signed certificates or certificates directly signed by the
 root CA certificate. However, there's a large number of certificates signed by
 an intermediate CA certificate, where this is a significant problem: A servlet
 will not have the possibility to validate the client certificate on its own. The
 bug would be fixed by passing on the <code>SSL_CLIENT_CERT_CHAIN</code> to Tomcat via the AJP connector.
 <br/>
 This directive exists only since version 1.2.22.
 <source>
   JkOptions     +ForwardSSLCertChain
 </source>

 <br/>
 <br/>
 </p>

 <p>
 The directive <b>JkEnvVar</b> allows you to forward environment variables from Apache server to Tomcat engine.
 The variables can be retrieved on the Tomcat side as request attributes.
 You can add a default value as a second parameter to the directive.
 If the default value is not given explicitely, the variable
 will only be send, if it is set during runtime.
 <br/>
 <br/>
 The variables are inherited from the global server to virtual hosts.

 <source>
   JkEnvVar     SSL_CLIENT_V_START     undefined
 </source>
 <br/>
 <br/>
 </p>

 </subsection>

 <subsection name="Assigning URLs to Tomcat">
 <p>
 If you have created a custom or local version of mod_jk.conf-local as noted above,
 you can change settings such as the workers or URL prefix.
 </p>
 <p>
 <b>JkMount</b> directive assign specific URLs to Tomcat.
 In general the structure of a JkMount directive is:
 </p>

 <source>
   JkMount [URL prefix] [Worker name]
 </source>

 <source>
   # send all requests ending in .jsp to worker1
   JkMount /*.jsp worker1
   # send all requests ending /servlet to worker1
   JkMount /*/servlet/ worker1
   # send all requests jsp requests to files located in /otherworker will go worker2
   JkMount /otherworker/*.jsp worker2
 </source>

 <p>
 You can use the JkMount directive at the top level or inside &lt;VirtualHost&gt;
 sections of your httpd.conf file.
 </p>
 <p><b>JkUnmount</b> directive acts as an opposite to JkMount and blocks access
 to a particular URL. The purpose is to be able to filter out the particular content
 types from mounted context. The following example mounts /servlet/*
 context, but all .gif files that belongs to that context are not served.
 </p>
 <source>
   # send all requests ending with /servlet to worker1
   JkMount /servlet/* worker1
   # do not send requests ending with .gif to worker1
   JkUnMount /servlet/*.gif worker1
 </source>
 <p>
 JkUnMount takes precedence over JkMount directives, meaning that the JK
 will first look for unmount and then for mount directives. The following
 example will block all .gif files.
 </p>
 <source>
   # do not send requests ending with .gif to worker1
   JkUnMount /*.gif worker1
   # The .gif files will not be mounted cause JkUnMount takes
   # precedence over JkMount directive
   JkMount /servlet/*.gif worker1
 </source>

 <p>
 <b>JkAutoAlias</b> directive automatically <b>Alias</b> webapp context directories into
 the Apache document space. It enables Apache to serve a static context while Tomcat
 serving dynamic context. This directive is used for convenience so that you don't
 have to put an apache Alias directive for each application directory inside Tomcat's
 webapp directory. For security reasons is is strongly recommended that JkMount
 is used to pass all requests to Tomcat by default and JkUnMount is used to
 explicitly exclude static content to be served by httpd. It should also be noted
 that content served by httpd will bypass any security constraints defined in the
 applciation's web.xml.
 </p>
 <source>
   # enter the full path to the tomcat webapps directory
   JkAutoAlias /opt/tomtact/webapps
 </source>
 <p>The following example shows how to serve a dynamic context by
 Tomcat and static using Apache. The webapps directory has to
 be accessible by apache.</p>

 <source>
   # enter the full path to the tomcat webapps directory
   JkAutoAlias /opt/tomtact/webapps

   # Mount 'servlets-examples' directory. It's physical location
   # is assumed to be in the /opt/tomtact/webapps/servlets-examples
   # ajp13w is a worker defined in the workers.properties
   JkMount /servlets-examples/* ajp13w

   # Unmount desired static content from servlets-examples webapp.
   # This content will be served by the httpd directly.
   JkUnMount /servlets-examples/*.gif ajp13w
   JkUnMount /servlets-examples/*.jpg ajp13w
 </source>
 <p>Note that you can have a single JkAutoAlias directive per virtual
 host inside your httpd.conf
 </p>
 <p>
 <b>JkWorkerProperty</b> is a new directive available from JK 1.2.7
 version. It is a convenient method for setting directives that are
 usually set inside <b>workers.propeties</b>file. The parameter for
 that directive is raw line from workers.properties file.
 </p>
 <source>
   # Just like workers.properties but exact line is prefixed
   # with JkWorkerProperty

   # Minimal jk configuration
   JkWorkerProperty worker.list=ajp13w
   JkWorkerProperty worker.ajp13w.type=ajp13
   JkWorkerProperty worker.ajp13w.host=localhost
   JkWorkerProperty worker.ajp13w.port=8009
 </source>
 <p>
 <b>JkMountFile</b> is a new directive available from JK 1.2.9
 version. It is used for dynamic updates of mount points at runtime.
 When the mount file is changed, JK will reload it's content.
 </p>
 <source>
   # Load mount points

   JkMountFile conf/uriworkermap.properties
 </source>
 <p>If the mount point uri starts with an exclamation mark '!'
 it defines an exclusion in the same way JkUnmount does.
 If the mount point uri starts with minus sign '-'
 the mount point will only be disabled. A disabled mount can be reenabled
 by deleting the minus sign and waiting for the JkMountFile to reload.
 An exclusion can be disabled by prefixing it with a mninus sign.
 </p>
 <source>
   # Sample uriworkermap.properties file

   /servlets-examples/*=ajp13w
   # Do not map .jpeg files
   !/servlets-examples/*.jpeg=ajp13w
   # Make jsp examples initially disabled
   -/jsp-examples/*=ajp13w
 </source>
 <p>At run time you can change the content of this file. For example
 removing minus signs will enable the previously disabled uri mappings.
 You can add any number of new entries at runtime that reflects the newly deployed
 applications. Apache will reload the file and update the mount
 points within 60 second interval.
 </p>
 <p>
 There is no way to delete entries by dynamic reloading, but you can disable or
 exclude mappings.
 <br/>
 <br/>
 </p>

 </subsection>

 <subsection name="Using SetHandler and Environment Variables">
 <p>
 Alternatively to the mod_jk specific directives, you can also use
 SetHandler and environment variables to control, which requests
 are being forwarded via which worker. This gives you more flexibility,
 but the results might be more difficult to understand. If you mix both
 ways of defining the forwards, in general to mod_jk directives will win.
 </p>
 <p>
 <b>SetHandler jakarta-servlet</b> forces requests to be handled by mod_jk.
 If you neither specify any workers via JkMount and the related directives,
 not via the environment variable described below,
 the first worker in the list of all worker will be chosen. You can use SetHandler
 for example in Location blocks or with Apache 2.2 also in RewriteRule.
 </p>
 <p>
 In order to control the worker using <b>SetEnvIf</b> or <b>RewriteRule</b>
 for more complex rules, you can set the environment variable <b>JK_WORKER_NAME</b>
 to the name of your chosen target worker. This enables you to decide on
 the chosen worker in a more flexible way, including dependencies on cookie values.
 This feature has been added in version 1.2.19 of mod_jk.
 </p>
 <p>
 In order to use another variable than <b>JK_WORKER_NAME</b>, you can set the name
 of this variable via the <b>JkWorkerIndicator</b> directive.
 </p>
 <p>
 Finally you can define exclusions from mod_jk forwards by setting the environment
 variable <b>no-jk</b>.
 </p>
 <source>
   # Automatically map all encoded urls
   &lt;Location *;jsessionid=&gt;
     SetHandler jakarta-servlet
     SetEnv JK_WORKER_NAME my_worker
   &lt;/Location&gt;

   # Map all subdirs to workers via naming rule
   # and exclude static content.
   &lt;Location /apps/&gt;
     SetHandler jakarta-servlet
     SetEnvIf REQUEST_URI ^/apps/([^/]*)/ JK_WORKER_NAME=$1
     SetEnvIf REQUEST_URI ^/apps/([^/]*)/static no-jk
   &lt;/Location&gt;
 </source>

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