No pain no gain

The installer script for the Python based web development framework Django contains a bug on OSX 10.5 which leads to problems with the default applications “admin”, “comments” and “sitemaps”. The template and media files of these applications are copied to a wrong directory.

As a workaround for this bug, you can copy the files manually to the correct location:

sudo cp -r /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/* /Library/Python/2.5/site-packages/django/contrib/

The long term support edition 8.04 of Ubuntu Linux will provide security updates until 2013. Therefore it is an ideal distribution for building the base of a secure hosting solution. In this article I will describe how you can setup the virtualization software OpenVZ on Ubuntu 8.04. OpenVZ allows you to run multiple virtual Linux servers on top of your Ubuntu system. It is extremely performant and OpenVZ is also the base of the well known Virtuozzo solution which is widely used in the web hosting market. Compared to Xen, OpenVZ is more limited in regards to different operating system you can run, but on the other hand it has a lower overhead and is therefore more performant. It is also possible to run OpenVZ inside of VirtualBox which is not possible with Xen.

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By default PHP scripts are compiled on each access. This will become a real performance killer once your website hits a certain load. There is a number of Opcode caches available which try to overcome this recompiling issue by storing precompiled versions of your scripts in a cache. This blog entry will explain how to integrate the Alternative PHP Cache (APC) into your PHP5 installation. This tutorial is based on a Debian installation, but it should also work with alternative distributions.

APC ist installed using the PHP Extension Community Library (PECL). Using PECL ist similar to using the PEAR Library. Before you can install APC via PECL, make sure that you have the following packages installed:

aptitude install php5-dev php5-gd

Downloading compiling and installation of APC using PECL ist a breeze. Just run from the command line:

pecl install APC

Now all you need to do is to add the following line to your php.ini file which you should find in /etc/php5/apache2/:

extension=apc.so

Once you restart Apache, caching will be enabled with default settings of APC. By default APC will use 30 MB memory to cache your PHP files. It is a good idea to tailor this setting to your server. This can be done with the following line in php.ini:

apc.shm_size=30