My WordPress blog has been successfully installed.

Now, I want to run the blog under a sub-domain i.e. http://blog.domain.com instead of http://host.domain.com/blog.

Let’s see how this can be done.

Initial googling points to apache and mod_rewrite. Let’s read more.

Oops, further googling shows that this can be done without using URL rewrites. Just use the built-in apache virtual hosts feature by adding the following to the config file (/etc/httpd/conf/httpd.conf in CentOS):

NameVirtualHost *:80

<VirtualHost *:80>
    ServerAdmin webmaster@blog.domain.com
    DocumentRoot /path/to/wordpress/directory
    ServerName blog.domain.com
    ErrorLog logs/blog.domain.com-error_log
    CustomLog logs/blog.domain.com-access_log common
</VirtualHost>

And.. voila! Not really. After doing this and restarting the apache service, http://blog.domain.com throws out a 404 error.

It turns out you need to change the WordPress working directory to the new URL via Settings>General before moving the files and implementing the virtual host. After that everything is OK.