ModJK_FAQ

Version 15

Created by ivelin.ivanov on Dec 20, 2004 11:49 PM. Last modified by lakagwu on Oct 20, 2008 11:10 AM.

Question: Which Tomcat connector should be used: mod_jserv, mod_jk, mod_jk2, mod_webapp or mod_proxy?

mod_jk is great and should be used for production. It is gettingfixes as needed (which is now rare).

mod_proxy. A cheap way to proxy without the hassles of configuringmod_jk. It allow you to use http/https and AJP. Since Apache httpd 2.2.x it has a reliable loadbalancing and sticky session handling. But it doesn't have yet all the features of mod_jk.

Avoid mod_jk2. Since mid November 2004 mod_jk2 is unsupported and no further development or maintenance of its code base will took

place.

Avoid mod_webapp, aka warp. It is deprecated and unsupported dueto lack of developer interest and there are better options such as

mod_jk and mod_jk2. mod_webapp WILL NOT run on windows.

mod_jserv at this point is unsupported and will not be supportedin Tomcat 5. mod_jserv was the original connector which supported the

ajp protocol.

Question: mod_jk 1.2.x is supposedly better than 2.0. Why?

Stability, simpler design, support and active development.

Mod_jk will be fully supported for all web servers. Lots of code from mod_jk2 has been ported to mod_jk. Mod_jk2 was meant to be the successorof mod_jk with pluggable communication channel architecture. Most of those extra channels like JNI or Unix sockets was platform specific. The JNI could be used only on single child process server mainly on WIN32 platform.

Also the APR was used for socket channel that made serious problems with Apache1.3.

So there was all that fuzzy channel architecture on top of single usable channel.

Also the mod_jk2 configuration was meant to be dynamic, meaning that one would be able to change the config on-the-fly, but that too was unusableand never implemented.

So finally you end up with something that is internally mod_jk but packed inside something called mod_jk2 and using completely different configuration system offering nothing more that JKalready doesn't offer.

From the development front a couple items were decided. First was to make sure there was a connector that is usable on as many platforms as

possible. Secondly, was to make a native Apache2 connectors distributed with the core Apache distribution, so that users don't need to build the connector by themselves or that there is a need to maintain binary distributions.

Taking all that into account, the decision was to stop further development of mod_jk2 and backport all it's usable goodies to mod_jk.

Also some redesign work was implemented exiting Apache's mod_proxy and added AJP protocol and load balancer, so that there is an integrated Tomcat support inside core Apache distribution.

http://jakarta.apache.org/tomcat/connectors-doc/news/20041100.html#20041115.1

mod_jk2 is officially unsupported mod_jk2 has been put in maintainer mode and no further development will take place. The reason for shutting

down mod_jk2 development was the lack of developers interest.

Another reason was lack of users interest in adopting mod_jk2, caused by configuration complexity when compared to mod_jk.

Mod_jk2 will have it's successor within core Apache2.2 distribution.

We have developed new proxy_ajp that is an addition to the mod_proxy and uses Tomcat's AJP protocol stack. It has been developed for httpd-2.2 and integrated in it.

We have also developed a new proxy_balancer module for load balancing http and ajp protocol stacks.

You can find more information at:

http://httpd.apache.org/docs-2.2/mod/mod_proxy.html

http://httpd.apache.org/docs-2.2/mod/mod_proxy_balancer.html

http://httpd.apache.org/docs-2.2/mod/mod_proxy_ajp.html

The actual version of mod_jk can be found at the following location:

http://jakarta.apache.org/tomcat/connectors-doc/