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diff --git a/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/miscellaneous/faq.xml b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/miscellaneous/faq.xml new file mode 100644 index 00000000..8525f815 --- /dev/null +++ b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/miscellaneous/faq.xml @@ -0,0 +1,324 @@ +<?xml version="1.0"?> +<!DOCTYPE document [ + <!ENTITY project SYSTEM "project.xml"> +]> +<document url="faq.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>FAQ</title> +<author email="hgomez@apache.org">Henri Gomez</author> +<date>$Date: 2009-03-05 12:42:14 +0100 (Thu, 05 Mar 2009) $</date> +</properties> +<body> +<section name="General"> +<p> +General Informations and FAQ about JK +</p> +<subsection name="Where can I get help/support for JK ?"> +<p> +The primary mechanism for support is through the JK +documentation included in the doc directory. +Documentation is also available on the Apache Tomcat web site devoted to the +<a href="http://tomcat.apache.org/connectors-doc/"> +Apache Tomcat Connectors Project</a> +For additional help, the best resource is the Tomcat Users Discussion list. +You should start by searching +<a href="http://mail-archives.apache.org/mod_mbox/tomcat-users/"> +the mail list archive</a> +before you post questions to the list. +If you are unable to locate the answer to your question in the archive, +you can post questions about JK to the user list for assistance. +Make sure that you include the version of your Webserver, +that you are using as well as the platform you are running on +and go +<a href="http://tomcat.apache.org/lists.html"> +here</a> +to determine how to subscribe to tomcat mailing list. +</p> +</subsection> + +<subsection name="I can't find JK anywhere. Where is it?"> +<p> +Now that JK moved to the <b>tomcat-connectors</b> repository, +the source and the binaries for JK can be downloaded from a mirror at the +<a href="http://tomcat.apache.org/download-connectors.cgi"> +Tomcat Connectors (mod_jk, mod_jk2) Downloads</a> page. +</p> +</subsection> + +<subsection name="What's the difference between JK and mod_jk ?"> +<br /> +<p> +<b>JK</b> is a project covering web-servers to Tomcat connectors, +whereas <b>mod_jk</b> is the <a href="../webserver_howto/apache.html">Apache module</a> developed in JK. +</p> + +<p> +<a href="../webserver_howto/iis.html">IIS webserver</a>support is implemented on JK, using a redirector +called <b>isapi redirector</b>. +</p> + +<p> +<a href="../webserver_howto/nes.html">Netscape/SunONE/Sun webserver</a>webserver support is implemented on JK, using a redirector +called <b>nsapi redirector</b>. +</p> + +</subsection> + +<subsection name="Where can I get more information ?"> +<p> +For <b>JK 1.2.x</b>, you should read : +</p> + +<ul> + +<li> +<a href="../generic_howto/quick.html">For the impatient</a> +</li> + +<li> +<a href="../webserver_howto/apache.html">Apache and JK</a> +</li> + +<li> +<a href="../webserver_howto/iis.html">IIS and JK</a> +</li> + +<li> +<a href="../webserver_howto/nes.html">Netscape/SunONE/Sun and JK</a> +</li> + +<li> +<a href="../generic_howto/workers.html">Workers configuration</a> +</li> +</ul> + +<p> +For more detailed information, have a look at the Reference Guide. +You could also try searching the mailing list archives for "JK" or look at the source. +</p> +</subsection> + +<subsection name="Which protocol should I use? Ajp12 or Ajp13?"> +<p> +<a href="../ajp/ajpv13a.html">Ajp13</a> is a newer protocol, it's faster, and it works better with SSL. +You almost certainly want to use it now that <strong>ajp12 is deprecated</strong>. +</p> +<p> +Also ajp13 is supported by all Apache Tomcat including 3.2.x , 3.3.x, 4.0.x, 4.1.x, 5.0.x, 5.5.x +and the new tomcat 6. +</p> + +<p> +Others Servlet engines like <b>jetty</b> have support for Ajp13. +</p> +</subsection> + +<subsection name="I've got a firewall between my web server and Tomcat which drops ajp13 connections after some time"> +<p> +Ajp13 uses persistant connections where the traffic could be null if there is no request to be sent to Tomcat. +Firewalls use to drop inactive connections and will make your web server and Tomcat think the connection is valid. +</p> +<p> +Starting with JK 1.2.0, a <b>socket_keepalive</b> property as been added to ajp13 settings, and you should take a look at +it in <a href="../generic_howto/workers.html">Workers HowTo</a> and +<a href="../reference/workers.html">workers.properties reference</a>. +If nothing else helps, you can try <b>JkOptions +DisableReuse</b>, but this will have strong performance implications. +</p> +</subsection> + +<subsection name="Under heavy load, I've got many threads in Tomcat even if my Apache Web Server handles much of the load"> +<p> +Under heavy load, Apache Web Server creates many children to handle the load, +which will in turn create many connections +to Tomcat to forward the requests they should handle. +Apache Web Server will normally kill the children/threads when the load decreases. +But if the load is still there and even if only Apache handles the requests, +ie static contents, the children are kept and with them all the ajp13 connections, +even if they are no more used. +</p> +<p> +To close connections after some time of inactivity you can use <b>connection_pool_timeout</b>, +for more informations refer to <a href="../reference/workers.html">workers.properties reference</a>. +</p> +</subsection> + +</section> + +<section name="Apache"> +<p> +Informations and FAQ about mod_jk and Apache Web Servers. +</p> +<subsection name="Whenever I restart Tomcat, Apache locks up!"> +<p> +The Ajp13 protocol keeps an open socket between Tomcat and Apache. +Release of mod_jk present in J-T-C handles the network failure. +But with very ancient releases of mod_jk, you may have to restart Apache as well. +</p> +</subsection> + +<subsection name="Why do there exist two files mod_jk.so (-eapi ad -noeapi) in download directories for Apache 1.3?"> +<p> +Many versions of Apache use a modified API, known at Extended API, developed for use with the +<a href="http://www.modssl.org">mod_ssl module</a>. Starting with Apache 2.0 there is no more difference. +</p> + +<p> +For example, Apache 1.3 present in certains recent Linux distributions include the +<b>mod_ssl</b> module. +</p> + +<p> +So if you got such 'Extended Apache', you need to use <b>mod_jk.so-eapi</b>. +</p> + +<p> +You should use <b>mod_jk.so-noeapi</b> only for 'Standard Apache' (ie without mod_ssl). +</p> + +<p> +It's wise to avoid using EAPI modules on STD API Apache or to use standard API modules on EAPI Apache. +Allways be sure to have the <b>mod_jk.so</b> witch match your version of Apache +</p> +</subsection> + +<subsection name="What's that message about 'garbled DSO ?'"> +<p> +It's related to Apache EAPI, the message <code>'mod_jk.so is garbled - perhaps this is not an Apache module DSO ?'</code> +just told you, that your're trying to install a mod_jk.so DSO module that was compiled on an Apache using EAPI, +like apache-mod_ssl or apache from Redhat distro 6.2/7.0 but your system use the standard apache with normal API. +</p> +</subsection> + +<subsection name="And the message about 'module might crash under EAPI!"> +<p> +Also related to EAPI, the message <code>'[warn] Loaded DSO /usr/lib/apache/mod_jk.so uses plain Apache 1.3 API, +this module might crash under EAPI! (please recompile it with -DEAPI)'</code>, the mod_jk.so was compiled under normal +Apache with standard API and you try to install the module on an Apache using EAPI. +</p> +</subsection> + +<subsection name="APXS is getting an error during the build of mod_jk, like rc=0 or rc=255. I tried all of the steps in the build section, what do I do now ?"> +<p> +APXS is a Perl script that is created when you build the Apache web server from source. +Chances are that if you are getting these errors and you obtained Apache as a binary distribution, +that APXS is not configured correctly for your system. +Your best bet is to get the Apache source from http://httpd.apache.org and build it yourself. +Use the following for a basic build (read the Apache docs for other options): +<screen> +<type>cd /usr/local/src</type><br/> +<type>gzip -dc apache_1.3.19.tar.gz|tar xvf -</type><br/> +<type>cd apache_1.3.19</type><br/> +<type>./configure --prefix=/usr/local/apache \</type><br/> +<type> --enable-module=most \</type><br/> +<type> --enable-shared=max</type><br/> +<type>make</type><br/> +<type>make install</type><br/> +</screen> +</p> +<p> +Note: The above steps assume that you downloaded the Apache source and placed it in your /usr/local/src directory. +</p> +</subsection> + +<subsection name="Apache 2.0 complains about incorrect module version"> +<p> +Since Apache 2.0 API still change often, the Apache 2.0 teams decide to put in headers of compiled modules the +Apache 2.0 version used to compile the module. This check is called Magic Module Number bump. +</p> +<p> +At start time Apache 2.0 check that version in modules headers and stop if it detect that a module was compiled +for another Apache 2.0 version. As such you should allways use modules compiled for the same Apache 2.0 version. +This check may be removed if the future. +</p> +</subsection> + +<subsection name="Does it work for Apache 2.2?"> +<p> +mod_jk works well with Apache 2.2. You need a binary module compiled for version 2.2 of the Apache web server. +A binary compiled for version 2.0 will not work. +</p> +<p> +Important parts of the functionality of mod_jk have been reimplemented as Apache httpd modules mod_proxy_ajp +and mod_proxy_balancer. These are part of the standard distributoin of Apache 2.2. The new modules do not contain +all features of mod_jk, but you get them automatically with every Apache 2.2. +</p> +</subsection> + +<subsection name="JNI doesn't work with Apache 1.3"> +<warn>JNI workers have been deprecated. They will likely not work. Do not use them.</warn> +<p> +JNI support requires a multi-threaded environment which is not the general case for Apache 1.3. +You should verify if Apache 1.3 has been build with thread support and if not you could add the +the pthreads library to your <b>httpd.conf</b> file. +</p> + +<source> + # Add pthread to Apache in httpd.conf + LoadModule "/usr/lib/libpthreads.so" +</source> + +<p> +Also keep in mind that JNI is suited for multi-threaded servers and you should consider upgrading +to Apache 2.x to support JNI. +</p> +</subsection> + +<subsection name="JNI report that JVM couldn't be started under Linux"> +<warn>JNI workers have been deprecated. They will likely not work. Do not use them.</warn> +<p> +Under Linux, you should set some environment variables BEFORE launching your Apache server : +</p> + +<screen> +<read>export LD_LIBRARY_PATH=$jre/bin:$jre/bin/classic:$LD_LIBRARY_PATH</read> +</screen> + +<p> +Also some Linux distributions have enabled a GLIBC feature called 'floating stacks' which may not works with kernel +less than 2.4.10 on SMP machines. You should disable floating stacks by exporting an environment variable : +</p> + +<screen> +<read>export LD_ASSUME_KERNEL=2.2.5</read> +</screen> + +<p> +You could have to update your service scripts, ie <b>/etc/rc.d/init.d/httpd</b>, to set these env vars +before your httpd server starts. +</p> +</subsection> + +<subsection name="Mixed errors when building via configure"> +<p> +configure assume you have some GNU tools already installed and configured for your system, and ad minima <b>libtool</b>. +</p> +<p> +Also some systems may have mixed cc and gcc setup which may make you puzzled when trying to link an Apache built with native +c compiler with a jk/jk2 build with gcc. +</p> +<p> +In case the make processing doesn't work as expected, you should use a GNU make <b>gmake</b>. +</p> +</subsection> + +</section> +</body> +</document> |