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From mt...@apache.org
Subject cvs commit: jakarta-tomcat-connectors/jk/xdocs/jk2 configwebcom.xml
Date Thu, 15 Apr 2004 06:32:34 GMT
mturk       2004/04/14 23:32:33

  Modified:    jk/xdocs/jk2 configwebcom.xml
  Log:
  Update few missing docs. Thanks to Agnus Mezick.
  
  Revision  Changes    Path
  1.17      +109 -37   jakarta-tomcat-connectors/jk/xdocs/jk2/configwebcom.xml
  
  Index: configwebcom.xml
  ===================================================================
  RCS file: /home/cvs/jakarta-tomcat-connectors/jk/xdocs/jk2/configwebcom.xml,v
  retrieving revision 1.16
  retrieving revision 1.17
  diff -u -r1.16 -r1.17
  --- configwebcom.xml	13 Mar 2004 07:33:24 -0000	1.16
  +++ configwebcom.xml	15 Apr 2004 06:32:33 -0000	1.17
  @@ -156,26 +156,26 @@
                           <th>Default</th>
                           <th>Description</th>
                       </tr>
  -                    <tr>
  -                        <td>file</td>
  -                        <td>No default value</td>
  -                        <td>Name of the file that will be mmapped to use as shared
memory, If set to 'anonymous' use the anonymous shered memory</td>
  -                    </tr>
  -                    <tr>
  -                        <td>size</td>
  -                        <td>No default value</td>
  -                        <td>Deprecated. Size of the file.</td>
  -                    </tr>
  -                    <tr>
  -                        <td>slots</td>
  -                        <td>256</td>
  -                        <td>Number of shared memory slots. Set to the number of child
processes</td>
  -                    </tr>
  -                    <tr>
  -                        <td>useMemory</td>
  -                        <td>0</td>
  -                        <td>Use process memory instead of shared memory. Useful for
single child mpm's</td>
  -                    </tr>
  +                    <tr>
  +                        <td>file</td>
  +                        <td>No default value</td>
  +                        <td>Name of the file that will be mmapped to use as shared
memory, If set to 'anonymous' use the anonymous shered memory</td>
  +                    </tr>
  +                    <tr>
  +                        <td>size</td>
  +                        <td>No default value</td>
  +                        <td>Deprecated. Size of the file.</td>
  +                    </tr>
  +                    <tr>
  +                        <td>slots</td>
  +                        <td>256</td>
  +                        <td>Number of shared memory slots. Set to the number of child
processes</td>
  +                    </tr>
  +                    <tr>
  +                        <td>useMemory</td>
  +                        <td>0</td>
  +                        <td>Use process memory instead of shared memory. Useful for
single child mpm's</td>
  +                    </tr>
                   </table>
               </p>
           </section>
  @@ -346,10 +346,18 @@
                           <tr>
                               <td>lb_factor</td>
                               <td>1</td>
  -                            <td>
  -    Load balancing factor to use. At this moment, it'll be set on the worker,
  -    but in future it should be possible to use lb on a channel level.
  -  </td>
  +                            <td>Load balancing factor to use. The lower the lb_factor
the more often that tomcat will get requests but see
  +                                "level" below.</td>
  +                        </tr>
  +                        <tr>
  +                            <td>level</td>
  +                            <td>1</td>
  +                            <td>Worker Priority.  Valid values are 0-3.  The functioning
workers with the lowest level
  +                                will be checked for the lowest lb_value, and if found will
be run.  The upper level workers are
  +                                only checked upon failure of all workers on ALL of the
levels below them.  This is very 
  +                                useful for implementing failover withing a cluster.  You
could set the tomcat server local 
  +                                on the same machine as the apache instance to level 0 and
all of the other workers to level 1.
  +                                This would cause apache to only use the external tomcats
when the local tomcat is down.</td>
                           </tr>
                           <tr>
                               <td>group</td>
  @@ -359,8 +367,13 @@
                           <tr>
                               <td>tomcatId</td>
                               <td>Automatically set to the localname ( host:port )</td>
  -                            <td>Must match the JVM route on tomcat Engine, for load
balancing</td>
  +                            <td>Must match the JVM route on tomcat the server.xml
Engine element, for load balancing</td>
                           </tr>
  +                        <tr>
  +                            <td>route</td>
  +                            <td>Automatically set to the localname ( host:port )</td>
  +                            <td>Same as tomcatId</td>
  +                        </tr>                        
                       </table>
                   </p>
               </subsection>
  @@ -409,7 +422,8 @@
                   </p>
               </subsection>
               <subsection name="ajp13">
  -                <p>Default worker</p>
  +                <p>Default worker.  If a property is in both the worker and the channel,
you only need to define it in one place.
  +                    The channel passes down the properties to its worker.  (at least in
the ajp13-channel.socket linkage)</p>
                   <p>
                       <table>
                           <tr>
  @@ -427,28 +441,39 @@
                           </tr>
                           <tr>
                               <td>tomcatId</td>
  -                            <td/>
  -                            <td/>
  +                            <td>Automatically set to the localname ( host:port )</td>
  +                            <td>Must match the JVM route on the tomcat server.xml
Engine element, for load balancing</td>
                           </tr>
                           <tr>
                               <td>route</td>
  -                            <td/>
  -                            <td/>
  +                            <td>Automatically set to the localname ( host:port )</td>
  +                            <td>Same as tomcatId</td>
                           </tr>
                           <tr>
                               <td>group</td>
  -                            <td/>
  -                            <td/>
  +                            <td>lb</td>
  +                            <td>loadbalanced groups to which this channel and the
associated worker will be added, multivalued. You need to set it only if you have an advanced
setup with multiple clusters.</td>
  +                        </tr>
  +                        <tr>
  +                            <td>lb_factor</td>
  +                            <td>1</td>
  +                            <td>Load balancing factor to use. The lower the lb_factor
the more often that tomcat will get requests but see
  +                                "level" below.</td>
                           </tr>
                           <tr>
                               <td>level</td>
  -                            <td/>
  -                            <td/>
  +                            <td>1</td>
  +                            <td>Worker Priority.  Valid values are 0-3.  The functioning
workers with the lowest level
  +                                will be checked for the lowest lb_value, and if found will
be run.  The upper level workers are
  +                                only checked upon failure of all workers on ALL of the
levels below them.  This is very 
  +                                useful for implementing failover withing a cluster.  You
could set the tomcat server local 
  +                                on the same machine as the apache instance to level 0 and
all of the other workers to level 1.
  +                                This would cause apache to only use the external tomcats
when the local tomcat is down.</td>
                           </tr>
                           <tr>
                               <td>channel</td>
                               <td/>
  -                            <td/>
  +                            <td>Communication channel used by the worker.  Use the
full name of the channel (everything between the []'s).</td>
                           </tr>
                           <tr>
                               <td>max_connections</td>
  @@ -574,7 +599,7 @@
                       <tr>
                           <td>level</td>
                           <td>INFO</td>
  -                        <td>Log level. Supported: EMERG, ERROR, INFO, DEBUG</td>
  +                        <td>Text of the log level. Strings supported: EMERG, ERROR,
INFO, DEBUG</td>
                       </tr>
                   </table>
               </p>
  @@ -603,5 +628,52 @@
               <subsection name="logger.apache2">
                   <p>Logger used in Apache2 servers, it normally in ends in error.log
</p>
               </subsection>
  +        </section>
  +    <section name="How Load Balancing Works">
  +        <p>The lb_factor and level properties combine to deliver a flexible static
load balancing solution.
  +            The level property is used to create up to four pools over workers in descending
priority and lb_factor
  +            is used to weight the workers within a pool.  The lower the level the more
likely the worker is to be used
  +            and the lower the lb_factor the more likely the worker is to be used.  Here
is how the algorithm is
  +            currently implemented:</p>
  +        <p>
  +(Assume that every worker's lb_value is set to their lb_factor)<br/>
  +<br/><source>
  +if (loadbalancer has a route) and (stickysession=1){<br/>
  +    worker= loadbanlancer.getWorkerForRoute(route)<br/>
  +    if worker.hasRedirect<br/>
  +        redirect=worker.redirect<br/>
  +    else if !worker.hasError<br/>
  +        return worker<br/>
  +    }<br/>
  +<br/>
  +selectedWorker=null<br/>
  +foreach lb_level {<br/>
  +    foreach worker in the level {<br/>
  +        if worker.isNotWorking<br/>
  +            continue<br/>
  +        if selectedWorker == null<br/>
  +            selectedWorker = worker<br/>
  +            continue<br/>
  +        if worker.lb_value &lt; selectedWorker.lb_value<br/>
  +            selectedWorker = worker<br/>
  +            continue<br/>
  +    }<br/>
  +    if selectedWorker !=null<br/>
  +        break<br/>
  +}<br/>
  +<br/>
  +Reenable workers in error state if the timeout has passed()<br/>
  +<br/>
  +if selectedWorker !=null {<br/>
  +    selectedWorker.lb_value += selectedWorker.lb_factor<br/>
  +    if selectedWorker.lb_value > 255 {<br/>
  +        foreach worker in load_balancer.workers[selectedWorker.level]<br/>
  +            worker.lb_value=worker.lb_factor<br/>
  +        }<br/>
  +    }<br/>
  +    return selectedWorker<br/>
  +}<br/></source>
  +</p>
  +            
       </section>
   </document>
  
  
  

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