Tag: unix domain socket

Lighttpd run php from different host using mod_proxy / mod_fastcgi

last updated in Categories High performance computing, Howto, lighttpd, Linux, UNIX

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.