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fcgi

Now, mod_fastcgi is configured and running. FastCGI supports connection via UNIX sockets or TCP/IP networking. This is useful to spread load among various backends. For example, php will be severed from 192.168.1.10 and python / ruby on rails will be severed from 192.168.1.11. This is only possible with mod_fastcgi.
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Lighttpd allows you to run php from different hosts. This is quite useful:

a] If you want to run php 4 locally and php 5 from remote host
b] Load balancing dynamic content
c] Added layer for security for chrooted jails etc

If you would like to run wikipedia / sf.net like site, you can use this technique. You can use mod_proxy or standard mod_fastcgi for this purpose.

How it works?

You need to use spawn-fcgi binary that spawns fastcgi processes. With spawn-fcgi you can bind php to particular port or unix-domain socket (little fast as compare to tcp port). It will take off some load from the webserver you have to control the FastCGI process by a external program like spawn-fcgi.

For example following command uses unix-domain to launch fastcgi process:
spawn-fcgi -s /tmp/php-fastcgi.sock -f /usr/bin/php-cgi -u lighttpd -g lighttpd -C 5 -P /var/run/spawn-fcgi.pid

This one bind itself to TCP port 8081
spawn-fcgi -p 8081 -a 192.168.1.10 -f /usr/bin/php-cgi -u lighttpd -g lighttpd -C 5 -P /var/run/spawn-fcgi-1.pid

Where,

  • -f {fcgiapp} filename of the fcgi-application, e.g php - /usr/bin/php-cgi
  • -a {addr} : bind to ip address
  • -p {port} : bind to tcp-port
  • -s {path} : bind to unix-domain socket
  • -C {childs} : (PHP only) numbers of childs to spawn (default 5)
  • -P {path} : name of PID-file for spawed process, so that we can kill process later on
  • -n : no fork (for daemontools)
  • -c {dir} : chroot to directory
  • -u {user} : change to user-id
  • -g {group} : change to group-id

Using mod_proxy / mod_fastcgi, we can process everything on 192.168.1.10 or cluster of php servers:

Web server <----> php-request <----> PHP listing on 192.168.1.10:8080 

A php / ruby / java app cluster server:

Web server <----> php-request <----> // PHP listing on 192.168.1.10:8080
                              // PHP listing on 192.168.1.11:8080
                             // PHP listing on 192.168.1.12:8080 

Task: Run php from 192.168.1.10 and 8081 port

Make sure you copy spawn-fcgi file to 192.168.1.10, now enter following command:
# spawn-fcgi -p 8081 -a 192.168.1.10 -f /usr/bin/php-cgi -u lighttpd -g lighttpd -C 10 -P /var/run/spawn-fcgi.pid
Make sure firewall is not blocking access to 192.168.1.10:8081

Now open ligttpd.conf on other host and enter mod_fastcgi as config as follows:

fastcgi.server = ( ".php" =>
   ((
       "host" => "192.168.1.10",
       "port" => 8081
   ))
)

Save and close the file. Restart lighttpd:
# /etc/init.d/lighttpd restart

You can use mod_proxy configuration as follows, if one of the hosts goes down the all requests for this one server are moved equally to the other servers.

$HTTP["host"] == "www.myweb2.0.com" {
  proxy.balance = "hash"
  proxy.server  = ( "" => ( ( "host" => "192.168.1.5","port" => 8080  ),
                            ( "host" => "192.168.1.6" ,"port" => 8080),
                            ( "host" => "192.168.1.7" ,"port" => 8080),
                            ( "host" => "192.168.1.8" ,"port" => 8080),
                            ( "host" => "192.168.1.9" ,"port" => 8080) ) )
}

This is just an introduction, feel free to explore mod_proxy documentation for more information.

Lighttpd PHP fastcgi configuration

Lighttpd logo

FastCGI is a language independent, scalable, open extension to CGI that provides high performance without the limitations of server specific APIs. FastCGI provides better scalability and performance. Instead of creating a new process (the CGI program) for every request, FastCGI uses a single persistent process which handles many requests over its lifetime. (See wikipedia article for more information)

Make sure php support fastcgi

Type any one of the following command to verify that php support fastcgi
$ php -v

Output:

PHP 5.0.4 (cli) (built: Nov  8 2005 08:27:12)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.0.4-dev, Copyright (c) 1998-2004 Zend Technologies

OR
$ php-cgi -v
Output:

PHP 5.0.4 (cgi-fcgi) (built: Nov  8 2005 08:25:54)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.0.4-dev, Copyright (c) 1998-2004 Zend Technologies

You must get string cgi-fcgi. Next find out full path to php-cgi or php binary:
$ which php-cgi
Output:

/usr/bin/php-cgi

Open lighttpd configuration file:
# vi /etc/lighttpd/lighttpd.conf

First add the module mod_fastcgi (lighttpd provides an interface to a external programs that support the FastCGI interface via this module). Make sure your server.modules loades mod_fastcgi:

server.modules              = (
            "mod_access",
            "mod_accesslog",
            "mod_fastcgi",
            "mod_rewrite",
            "mod_auth"
)

Now add following lines to configuration:

fastcgi.server = ( ".php" => ((
                     "bin-path" => "/usr/bin/php-cgi",
                     "socket" => "/tmp/php.socket"
                 )))

Save the configuration and close all the files. Restart the lighttpd:
# /etc/init.d/lighttpd restart

Test your configuration by running php program or application.

See also