Megalinux

Apache provides a very easy method to provide hosting for dynamically created sub-domains with “VirtualScriptAlias” and “VirtualDocumentRoot” syntaxes

Lets say, we have mydomain.com, and you need to dynamically configure test.mydomain.com, monkey.mydomain.com etc. (and not required to manually configure apache or restart), then..

Step 1: Configure wild-card DNS, so that *.mydomain.com is a cname to mydomain.com

Step 2: Configure apache. Create a new virtualhost section for *.mydomain.com, like:

<VirtualHost *>
ServerAlias *.mydomain.com
CustomLog /www/www.logs/virtual.mydomain.com-access_log combined
ErrorLog /www/www.logs/virtual.mydomain.com-error_log
VirtualDocumentRoot /www/www.mydomain.com/virtualdomains/%0/docs
VirtualScriptAlias  /www/www.mydomain.com/virtualdomains/%0/cgi-bin/
</VirtualHost>

Step 3: Restart apache to activate the new configuration

Step 4: Now, say you need test.mydomain.com, all that is required is to create /www/www.mydomain.com/virtualdomains/test.mydomain.com/docs and /www/www.mydomain.com/virtualdomains/test.mydomain.com/cgi-bin/

Technorati Tags: apache, dynamic, subdomain, virtualhosting

If you have issues with tomcat not able to parse/display UTF characters, try adding URIEncoding=”UTF-8″ to your tomcat settings (server.xml).

Example:

<Connector port=”8080″ maxThreads=”150″ minSpareThreads=”25″ maxSpareThreads=”75″ enableLookups=”false” redirectPort=”8443″ acceptCount=”100″ debug=”0″ connectionTimeout=”20000″ disableUploadTimeout=”true” URIEncoding=”UTF-8″/>

Make sure you set IPCCommTimeout to at least 45 to allow enough startup
time.
Set DefaultMaxClassProcessCount to 2 unless your benchmarks tell you to
change.
Set IdleTimeout to 3600 or higher since your only have 2 dispatch.fcgi.
Set ProcessLifeTime to a multiple of IdleTimeout.
Set MaxProcessCount > DefaultMaxClassProcessCount so you can use
mod_fcgid for other things than rails.

mod_fcgid religiously kills idle or old processes so keep IdleTimeout
and ProcessLifeTime to high values.

Here is an example ‘starter’ /etc/apache2/mods-enabled/fcgid.conf

AddHandler fcgid-script .fcgi
SocketPath /var/lib/apache2/fcgid/sock
IdleTimeout 3600
ProcessLifeTime 7200
MaxProcessCount 8
DefaultMaxClassProcessCount 2
IPCConnectTimeout 8
IPCCommTimeout 60
DefaultInitEnv RAILS_ENV production

If you have plenty of RAM, then increase DefaultMaxClassProcessCount to
about 2*CPU–assume each instance will eat 20-30MB RAM.

After updating ruby and ruby-on-rails, I got this following error in my error log:

Permission denied: mod_fcgid: couldn’t bind unix domain socket /etc/httpd/logs/fcgidsock/

Solution: chmod 555 /etc/httpd/logs (this is a symlink to /var/httpd/logs)