Posts Tagged ‘cPanel Tutorial’

Apache and Tomcat via Cpanel – Servlet Display Problems

March 29th, 2010

Problem

Apache Web Server was not passing servlet requests to Apache Tomcat. Instead it served 404 errors, even though the Apache Tomcat Connector (JK 1.2, mod_jk) was auto-configured by the WHM / Cpanel installation.

Other Possible Descriptions of the Problem

  • Jsp’s work in Tomcat, but servlets do not
  • Apache Http Server won’t pass servlet requests to Tomcat
  • Tomcat problems using the Cpanel plugin
  • Virtual host configuration problem with Cpanel Tomcat
  • Apache not recognizing servlets
  • Servlets can’t be accessed through Apache

In the latest Cpanel Release (11.15.0-RELEASE 17853), Tomcat support has been integrated. Prior to this (I’m not sure for how long), Tomcat was available via a beta plug-in. I experienced this problem with both the beta plug-in and the integrated support.

What’s Happening

Apache Http Server accepts all web requests and determines which are requests for static content, and which requests should be forwarded to Tomcat.

Apache correctly serves static content, and correctly passes all requests for .jsp pages to Tomcat. But when a servlet is requested, e.g. www.myserver.com/myapp/myservlet, Apache looks for the “/myapp/myservlet” directory, and finding none, spits out a 404 error.

How to Resolve the Problem

I tried several things that I thought should work but did not, though I don’t know if it was due to my specific configuration or because they were just the wrong things to do. What finally solved the problem was just adding an .htaccess file to the root of the web application with the following lines:

SetHandler jakarta-servlet
SetEnv JK_WORKER_NAME ajp13

This forces Apache to forward all requests to resources within this context to Tomcat for processing, specifically to worker ajp13. Ajp13 is one of the default workers set up, and is defined (on my system) in /usr/local/jakarta/tomcat/conf/workers.properties.

Other things that I thought should work but didn’t (your mileage may vary):

1) In /etc/httpd/conf/jk.conf (if your httpd.conf file includes jk.conf),
add/edit the switch “+ForwardDirectories.” Normally, if Apache runs
across a directory it doesn’t recognize, it will spit out a 404. This
switch says to forward those requests to Tomcat, and let Tomcat spit
out a 404 if it can’t fulfill the request.

2) In /etc/httpd/conf/jk.conf (if your httpd.conf file includes jk.conf), specifically mount each context, and unmount static content. Mounting tells Apache to pass requests to Tomcat, and unmounting tells Apache to serve the content itself. Newer versions of Tomcat are faster than Apache at serving static content, but apparently, using Apache to serve static content is safer from a security perspective.

JkMount /mywebapp/* ajp13
JkUnMount /*.gif ajp13
JkUnMount /*.jpg ajp13

A separate issue that is outside the scope of this post is whether you should use Apache Web Server to front Tomcat requests, or whether you should just have Tomcat accept requests over port 80. If you’re using a recent Tomcat version (5.5+), Tomcat can serve both static and dynamic content faster than Apache.

Use Tomcat if: 1) you’re only dealing with a single server; 2) and you’re not using any other software that requires Apache (e.g. forums or wikis written in PHP).

Use Apache to front Tomcat requests if: 1) you want to load balance across multiple servers; 2) or you want different web applications or virtual hosts to be served by different processes.

Disclaimer

I know embarrassingly little about hardware, networking, or server setup. This solution might be a hack or it might be obvious to some more familiar with the components mentioned, but it couldn’t be resolved through a dedicated server help desk or through the Cpanel help desk, so I assume there are others out there that this could help. Everything in this post is based on my limited experience with the aforementioned software and my own research. If you know of a better, cleaner way to do this, or if you know how better to describe this problem or solution, please forward to me and I’ll amend this post.

Rationale Behind this Post

I recently (as in yesterday) resolved a difficult to diagnose problem involving Cpanel, Apache Web Server, Apache Tomcat, and the Apache Tomcat Connector (JK 1.2, mod_jk2). My googling skills tend to be above average, but I could find no reference to this specific problem anywhere, and the sole purpose of this post is to hopefully save someone else the aggravation. So please disregard the keyword-heavy text — it’s altruistic in nature, I assure you.

25 comments »

Posted in Apache tomcat, cPanel Tutorial

Tags:

cPanel Tutorial: Working with Mailing Lists

January 15th, 2010

Mailing lists are among the most underrated features in any hosting account, incredibly useful for online businesses that want to stay in touch with their customers by keeping them informed with regular updates regarding their products or services.  There are several mailing list scripts available online in both the free and paid variety.  If you use cPanel as your control panel, you don’t have to worry about searching for them as a serviceable script is already bundled into the software.  Known as Mailman, this program allows you create mailing lists with varying options such as contacts on the list, where the mail will be sent and much more.  This cPanel tutorial will walk you through the process of adding, editing and deleting mail lists right from your control panel.

How to Create Mailing Lists

- Login to your cPanel and click the “Mailing Lists” icon under the “Mail” category.

- On the “Mailing lists” page, click the “Add Mailing List” link.

- Next, enter a name for your mailing list and a password in the appropriate fields.  Make sure you confirm the password on the next line.

- Choose the domain the mailing list will be used on from the list of options provided in the drop-down menu.

- Lastly, click the “Create” button.

How to Edit Mailing Lists

Creating a mail listing is easy.  Editing them is just as simple.  The Mailman script makes a large number of configuration options available to you and the steps below will show you how to go about accessing them.

- Login to your cPanel account and click on the “Mailing List” icon underneath the “Mail” category.

- On the Mailing List page, you can find your mailing lists by using the handy search function.  Once you find it, login to the list you just created with the password you assigned.  Doing so will open up a separate administrative panel that allows you to play around with the settings and options.

How to Delete Mailing Lists

If you have mailing lists you want to delete for whatever reason, don’t worry because removing them is easy.  You can even delete multiple lists simultaneously if you choose to.  Before proceeding, we must warn you that by deleting a mailing list, you will also be deleting all the data it contains.  This includes existing messages, archives and member email addresses.  If you feel that you will need this information later on down the road, you should either copy those files or download them to your local hard drive before deleting them.  Keeping this in mind, follow the steps below:

- Login into cPanel and click the “Mailing Listing” icon under the “Mail” category.

- On the “Mailing Lists” page, click the “Mailing Lists” link.

- Next, simply click the “Delete” button next to the list you want to delete.

- Finally, confirm the deletion by clicking the “Yes” button.

Conclusion:

There you have it.  Now that you know how to create mailing lists, you can enjoy a more effective way to manage your email campaigns and stay in touch with your clients.

28 comments »

Posted in Control panels

Tags:

PHP Freelancer