Tomcat Connector - Configuring Apache

# Tomcat Connector ## Configuring Apache |
Configuration Directives
> Here are the all directives supported by Apache:
> Directive | Description
> --- | ---
> `JkWorkersFile` | The name of a worker file for the Tomcat servlet containers
> `JkWorkerProperty` | Enables setting workers.properties inside Apache configuration file. This directive is available in jk1.2.7 version and later.
> `JkMount` | A mount point from a context to a Tomcat worker
> `JkMountFile` | File containing multiple mappings from a context to a Tomcat worker
> `JkUnMount` | A no mount point from a context to a Tomcat worker This directive is available in jk1.2.7 version and later.
> `JkMountCopy` | Should the base server mounts be copied to the virtual server.
> `JkLogFile` | Full or server relative path to the Tomcat Connector module log file
> `JkLogLevel` | The Tomcat Connector module log level, can be debug, info, warn error or trace
> `JkLogStampFormat` | The Tomcat Connector module date log format, follow strftime syntax
> `JkRequestLogFormat` | Request log format string. See detailed description below.
> `JkAutoAlias` | Automatically Alias webapp context directories into the Apache document space.
> `JkHTTPSIndicator` | Name of the Apache environment variable that contains SSL indication
> `JkCERTSIndicator` | Name of the Apache environment variable that contains SSL client certificates
> `JkCIPHERIndicator` | Name of the Apache environment variable that contains SSL client cipher
> `JkSESSIONIndicator` | Name of the Apache environment variable that contains SSL session
> `JkKEYSIZEIndicator` | Name of the Apache environment variable that contains SSL key size in use
> `JkExtractSSL` | Turns on SSL processing and information gathering by mod_jk
> `JkOptions` | Set one of more options to configure the mod_jk module. See below for details about this directive
> `JkEnvVar` | Adds a name of environment variable that should be sent to servlet-engine
> `JkShmFile` | Shared memory file name. Used only on unix platforms.
> `JkShmSize` | Size of the shared memory file name. Default is 64 k.
Configuration Directives Types
> We'll discuss here the mod_jk directive types.
> Define workers
> > JkWorkersFile specify the location where mod_jk will find the workers definitions. Take a look at Workers documentation for detailed description.
> >       JkWorkersFile     /etc/httpd/conf/workers.properties
> Logging
> > JkLogFile specify the location where mod_jk is going to place its log file.
> >       JkLogFile     /var/log/httpd/mod_jk.log
> > 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:
> >       JkLogFile     "|/usr/bin/rotatelogs /var/log/httpd/mod_jk.log 86400"
> > JkLogLevel set the log level between : info log will contain standard mod_jk activity (default). warn log will contain non fatal error reports. error log will contain also error reports. debug log will contain all information on mod_jk activity trace log will contain all tracing information on mod_jk activity
> >       JkLogLevel    info
> > info should be your default selection for normal operations. JkLogStampFormat will configure the date/time format found on mod_jk log file. Using the strftime() format string it's set by default to "[%a %b %d %H:%M:%S %Y]"
> >       JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
> > JkRequestLogFormat 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:
> > Options | Description
> > --- | ---
> > `%b` | Bytes sent, excluding HTTP headers (CLF format)
> > `%B` | Bytes sent, excluding HTTP headers
> > `%H` | The request protocol
> > `%m` | The request method
> > `%p` | The canonical Port of the server serving the request
> > `%q` | The query string (prepended with a ? if a query string exists, otherwise an empty string)
> > `%r` | First line of request
> > `%s` | Request HTTP status code
> > `%T` | Request duration, elapsed time to handle request in seconds '.' micro seconds
> > `%U` | The URL path requested, not including any query string.
> > `%v` | The canonical ServerName of the server serving the request
> > `%V` | The server name according to the UseCanonicalName setting
> > `%w` | Tomcat worker name
> >       JkRequestLogFormat     "%w %V %T"
> > You can also log mod_jk information using the Apache standard module mod_log_config. 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.
> > Note | Description
> > --- | ---
> > `JK_WORKER_NAME` | Name of the worker selected by the URI mapping
> > `JK_WORKER_TYPE` | Type of the worker selected by the URI mapping
> > `JK_REQUEST_DURATION` | Request duration in seconds and microseconds. At the moment only available if JkRequestLogFormat is set.
> > `JK_LB_FIRST_NAME` | Load-Balancer: Name of the first worker tried
> > `JK_LB_FIRST_TYPE` | Load-Balancer: Type of the first worker tried
> > `JK_LB_FIRST_ACCESSED` | Load-Balancer: Access count for the first worker tried
> > `JK_LB_FIRST_READ` | Load-Balancer: Bytes read for the first worker tried
> > `JK_LB_FIRST_TRANSFERRED` | Load-Balancer: Bytes transferred for the first worker tried
> > `JK_LB_FIRST_ERRORS` | Load-Balancer: Error count for the first worker tried
> > `JK_LB_FIRST_BUSY` | Load-Balancer: Busy count for the first worker tried
> > `JK_LB_LAST_NAME` | Load-Balancer: Name of the last worker tried
> > `JK_LB_LAST_TYPE` | Load-Balancer: Type of the last worker tried
> > `JK_LB_LAST_ACCESSED` | Load-Balancer: Access count for the last worker tried
> > `JK_LB_LAST_READ` | Load-Balancer: Bytes read for the last worker tried
> > `JK_LB_LAST_TRANSFERRED` | Load-Balancer: Bytes transferred for the last worker tried
> > `JK_LB_LAST_ERRORS` | Load-Balancer: Error count for the last worker tried
> > `JK_LB_LAST_BUSY` | Load-Balancer: Busy count for the last worker tried
> >       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
> Forwarding
> > The directive JkOptions allow you to set many forwarding options which will enable (+) or disable (-) following option. JkOptions ForwardKeySize, 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).
> >       JkOptions     +ForwardKeySize
> > JkOptions ForwardURICompat, you ask mod_jk to send the URI to Tomcat normally, which is less spec compliant but mod_rewrite compatible, use it for compatibility with Tomcat 3.2.x engines (on by default).
> >       JkOptions     +ForwardURICompat
> > JkOptions ForwardURICompatUnparsed, the forwarded URI is unparsed, it's spec compliant but broke mod_rewrite.
> >       JkOptions     +ForwardURICompatUnparsed
> > JkOptions ForwardURIEscaped, the forwarded URI is escaped and Tomcat (since 3.3 rc2) will do the decoding part.
> >       JkOptions     +ForwardURIEscaped
> > JkOptions ForwardDirectories is used in conjunction with DirectoryIndex directive of Apache web server. As such mod_dir should be available to Apache, statically or dynamically (DSO) 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). 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 403 Forbidden response (if directive Options doesn't specify Indexes for that directory). 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. 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.
> >       JkOptions     +ForwardDirectories
> > JkOptions ForwardLocalAddress, 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.
> >       JkOptions     +ForwardLocalAddress
> > JkOptions FlushPackets, you ask mod_jk to make a flush after each AJP packet received from Tomcat.
> >       JkOptions     +FlushPackets
> > JkOptions DisableReuse, 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. 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.
> >       JkOptions     +DisableReuse
> > The directive JkEnvVar allow you to forward an environment vars from Apache server to Tomcat engine.
> >       JkEnvVar     SSL_CLIENT_V_START
> Assigning URLs to Tomcat
> > 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. JkMount directive assign specific URLs to Tomcat. In general the structure of a JkMount directive is:
> >       JkMount [URL prefix] [Worker name]
> >       # 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
> > You can use the JkMount directive at the top level or inside <VirtualHost> sections of your httpd.conf file. JkUnmount 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.
> >       # send all requests ending with /servlet to worker1
> >       JkMount /servlet/* worker1
> >       # do not send requests ending with .gif to worker1
> >       JkUnMount /servlet/*.gif worker1
> > 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.
> >       # 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
> > JkAutoAlias directive automatically Alias 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.
> >       # enter the full path to the tomcat webapps directory
> >       JkAutoAlias /opt/tomtact/webapps
> > 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.
> >       # 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
> > Note that you can have a single JkAutoAlias directive per virtual host inside your httpd.conf JkWorkerProperty is a new directive available from JK 1.2.7 version. It is a convenient method for setting directives that are usually set inside workers.propetiesfile. The parameter for that directive is raw line from workers.properties file.
> >       # 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
> > JkMountFile 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.
> >       # Load mount points

> >       JkMountFile conf/uriworkermap.properties
> > If mount point uri starts with minus '-' char the mount point will be disabled.
> >       # Sample uriworkermap.properties file

> >       /servlets-examples/*=ajp13w
> >       # Do not map .jpeg files
> >       !/servlets-examples/*.jpeg=ajp13w
> >       # Make jsp examples initially disabled
> >       -/jsp-examples/*=ajp13w
> At run time you can change the content of this file. For example removing minus char will enable the uri mapping. 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.
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