How to configure mod_proxy_ajp with Tomcat ?

mod_proxy_ajp is an Apache module which can be used to forward a client HTTP request to an internal Tomcat application server using the AJP protocol.

To respond to the question "Why should I use mod_proxy_ajp rather than a classic mod_proxy ?", here is a small recap:

You can gain a lot of flexibility (lot of the apache modules/features can be used especially "name-based virtual hosting")
Practical for those who need to support Java applications along with PHP / Perl … (only one apache server is needed)
Certificates management is easier in apache configuration (this argument is a lot subjective)
It's not Tomcat's main objective to serve http static resources (not optimized for that)
Load balancing/cluster management is easier with an apache frontend

Tomcat configuration

You just have to create the AJP connector in the conf/server.xml file like that:

<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />

This line will enable AJP connections to the 8009 port of your tomcat server (localhost for example).

Apache2 configuration

One way (useful if this apache is a global front end) is to create a virtual host for this application.

Listen 1979
NameVirtualHost *:1979
<VirtualHost *:1979>
   ServerName localhost
   ErrorLog /var/log/apache2/ajp.error.log
   CustomLog /var/log/apache2/ajp.log combined
 
   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>
 
   ProxyPass / ajp://localhost:8009/
   ProxyPassReverse / ajp://localhost:8009/
</VirtualHost>

ProxyPass and ProxyPassReverse are classic reverse proxy directives used to forward the stream to another location.
ajp://... is the AJP connector location (your tomcat's server host/port)

A web client will connect through HTTP to http://localhost:1979/ (supposing your apache2 server is running on localhost), the mod_proxy_ajp will forward you request transparently using the AJP protocol to the tomcat application server on localhost:8009.

article, computing, proxy, ajp, apache, tomcat

Discussion

Munkhbayar, 2008/11/26 09:44

Hi. I follewed the above inctoructions and I got this:

Forbidden

You don't have permission to access /testAJP/index.jsp on this server.

What was wrong with me? and What should i do to resolve this?

Stéphane Gully, 2008/11/27 08:14

Try to look at the apache log and at the tomcat log to see which one is blocking the access.

TyPham, 2009/03/25 05:37

Hi, I want to configure this mod_proxy_ajp with Glassfish instead Tomcat, in this case does it support?

Stéphane Gully, 2009/07/03 19:49

I don't know, I never used Glassfish.

Konstantin Petrukhnov, 2009/06/18 10:24

Thanks! it is most clearest explanation that i found in the internet. ErrorLog, CustomLog are optional If you specify <VirtualHost www.strangehostname.net:80> Then it will handle only requests that will go to www.strangehostname.net:80 All other requests will not be handled by this proxy.

Tip: you could specify separate ajp port per each service in tomcat. And then assign them to different hostnames in apache.

Shiva, 2009/07/03 19:40

Please tell me what are all the modules in APACHE 2.2.10 needs to be enabled…

Thanks in advance

Stéphane Gully, 2009/07/03 19:48

Its name is mod_proxy_ajp.

..alee, 2009/07/15 17:13

one of the best explanation. I have been trying to work on it since yesterday but could not figure it out. but now it's working

ok one question, i want to add ProxyPassMatch directive. If i put in VirtualHost then it gives me error. Can someone help?

<VirtualHost *:80>
   ServerName localhost
   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>
 
   ProxyPass / ajp://localhost:8009/
   ProxyPassReverse / ajp://localhost:8009/
   #ProxyPassMatch ^(/photos/.*\.jpg)$!
 
   Alias /photos "F:\projects\AL\Photos"
 
   <Directory "F:\projects\AL\Photos">
       Options Indexes MultiViews
       AllowOverride None
       Order allow,deny
       Allow from all
   </Directory>
 
</VirtualHost>

Nirmal, 2009/10/01 13:45

Thank You Very Much for the post. Saved me like nothing.

Thanks again.

Marc, 2010/07/15 15:40

Just installed apache2. There is no conf/server.xml file.

Cv, 2010/07/21 22:07

Marc, that file resides in your tomcat installation.

mansi, 2010/07/23 07:04

can you tell in which file following could i should place…

Listen 1979
NameVirtualHost *:1979
<VirtualHost *:1979>
   ServerName localhost
   ErrorLog /var/log/apache2/ajp.error.log
   CustomLog /var/log/apache2/ajp.log combined
 
   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>
 
   ProxyPass / ajp://localhost:8009/
   ProxyPassReverse / ajp://localhost:8009/
</VirtualHost>

Sabine , 2010/11/12 09:48

Hi there,

does AJP only work with localhost or can I point to a different host? If so do I have to enable anything on the other host so it accepts AJP requests?

Thank you,

Sabine

Stéphane Gully, 2010/11/14 21:05

Of course you can connect to other host. The only thing that should be configured on the destination host is the firewall: it has to allow connections on the AJP port (8009 on this example)

shoukat, 2010/11/25 01:19

thanks for the post. you saved my weekend.

rodrigo, 2011/02/02 23:54

question, I can declare two AJP's with different IP, the first IP is a different server, the second with localhost

Example

 ProxyPass /myPortal ajp://15.15.162.50:8009/
 ProxyPassReverse /myPortal ajp://15.15.162.50:8009/

 ProxyPass / ajp://localhost:8009/
 ProxyPassReverse / ajp://localhost:8009/

Of course, this does not work, but is there any way to fix it

Stéphane Gully, 2011/02/03 09:16

Yes, it will work.

Scott, 2011/06/12 06:41

I have a QNAP TS-110 NAS. The Apache "modules" folder shows the mod_so.so, mod_proxy_ajp.so and mod_proxy.so files. "apachectl -l" shows the "mod_so.c" compiled into Apache. "apachectl -M" shows only the "so_module" as loaded. The "LoadModule" commands for all 3 files mentioned above are present in the "httpd.conf" file.

Are you familiar or know someone else who figured away around the QNAP setup to enable Apache and Tomcat to interface via AJP protocol?

I tried your suggestion above but it didn't resolve the problem of Apache and Tomcat not being able to communicate. Tomcat is accessible if I specify Tomcat's port number in the URL (http :// 192.168.1.68:7080/).

I'd appreciate any assistance you could provide.

How to configure mod_proxy_ajp with Tomcat ?

Tomcat configuration

Apache2 configuration

What's the result ?

Discussion

Categories

Partners