Tomcat 6.0.18, Apache 2.2.9, proxy_ajp on Ubuntu 8.10: Almost Trivial...

Wed, 24 Dec 2008 02:15:11 GMT

... after four hours of documentation re-reading.

[Update Tue Dec 23 15:30:20 CST 2008] The above line was written two days ago when I moved this blog away from a dying PC. Regular readers might have noticed outages of this blog for stretches of several hours at a time and during the evening hours. The whole machine would lock up while the disk light is a solid on, presumably trying to read something off the disk.

This is the second time a PC has died at home. If you remember, gao-2002 went out of commission only 23 days ago. And now gao-2006 is gone. You've seen gao-2006 mentioned here, here, here, and here.

Luckily, I was able to save all the data from the dying PC before it finally would get a kernel panic during the boot up process. I felt that I was this close to writing a different blog entry that begins: "I'm an idiot and I lost all data in this blog..."

Are your data backed up? Now would be a good time to implement your backup strategy.

With the backed up data, I was able to setup this blog on gao-2009 within four hours, most of it spent on one task. Here's entire process on this Ubuntu 8.10 machine:

Install sun-java6-jdk from Synaptic Package Manager
Install apache2 from Synaptic Package Manager
Install tomcat6 from Synaptic Package Manager
Deploy my blog at /var/lib/tomcat6/webapp/blog
Connecting apache2 to tomcat6

The first four steps are trivial. I did the first three prior to the move. Step 4 took minutes. Step 5 is also trivial, but I didn't know it when I started. What tripped me up is Google. Most of the search results leads to outdated information. And I spent a number of hours following the wrong leads, most of them about mod_jk, which I custom compiled in the early days of this blog.

It finally downed on me that perhaps I should read the documentations. And what a good idea what was. All I need to know is in the documentations:

The gist of the documentation can be distilled to three sentences: Apache 2.2.9 includes mod_proxy_ajp support. Tomcat 6.0.18 is configured with an AJP connector by default. All I need to do is to enable mod_proxy_ajp and then tell it where my webapp is.

To enable mod_proxy_ajp I used the command:

[root@gao-2009] # a2enmod mod_proxy_ajp

To tell Apache 2.2.9 where my webapp is I added /etc/apache2/conf.d/proxy_ajp with the following content:

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

<Proxy /blog>
  Order deny,allow
  Allow from all
</Proxy>

It turns out I also need to edit /etc/apache2/mods-enabled/proxy.conf to change a line that says Deny from all into Allow from all. Without this change, noone can access the blog and I get error message that reads:

... client denied by server configuration: proxy:ajp://localhost:8009/...

That's all there is to it.

Upgraded Weblog Software To Pebble 2.3.1

Fri, 08 Aug 2008 04:51:15 GMT

You won't feel it too much, but I have migrated this blog from gao-2002 (a.k.a my wife's workstation) to gao-2006 (my workstation), in order to give gao-2002 a much needed OS upgrade, from Fedora Core 6 to something newer, maybe Fedora 9.

I had a false start on Sunday when my first attempt resulted in some errors. I spent the last few evenings experimenting with different migration procedures. The final move this evening took me about 27 minutes, from 8:43pm to 9:10pm, most of the time was spent on customizing the page templates.

Here's some parameters of the new setup of this blog:

AMD Athlon(tm) 64 Processor 3500+
cpu MHz: 2210.216
Debian GNU/Linux 4.0
Java 6 OpenJDK
Apache Web Server 2.2.3
apache2.2-common including proxy_ajp
Tomcat 5.5.26
Pebble 2.3.1
JavaMail 1.4.1

[Update] I'm having some additional challenges with the new setup. When I saved this blog entry, I received an error page. I'll see if I can get this blog entry published by some other means. The worse thing that can happen is this blog may become unreadable for a short time.

[Update] The above attempt did result in the home page not rendering correctly. I reindexed the whole blog. I hope this time it works.

[Update] OK. It finally worked. It's 11:46pm now. Time for bed.

Weiqi Gao's Observations - tomcat tag

Tomcat 6.0.18, Apache 2.2.9, proxy_ajp on Ubuntu 8.10: Almost Trivial...

Upgraded Weblog Software To Pebble 2.3.1