Background
- The goal of this presentation is to serve PHP4 and PHP5 content concurrently on the same Apache server using FastCGI.
- PHP normally runs as an Apache module.
- Apache + mod_php4 + mod_php5 = sefaulting badness
- PHP can also run as a CGI program. This is generally slower than the module approach, but the key here is flexibility rather than performance.
- FastCGI is much faster than normal CGI.
- My very incomplete benchmarks showed PHP5 as FastCGI to have about 80% of the performance of mod_php5. (Measuring requests/second via ab, Apache Benchmark.)
Setup
This is the testing setup I put together :
- Linux (This setup works on Windows, but all my examples are on Linux.)
- Apache 2.0.59
- PHP 4.4.4, compiled as an Apache module
- PHP 5.1.5, compiled as a FastCGI binary
- mod_fastcgi 2.4.2
A note on binaries
- There are binary packages available for all the software used in this presentation.
- These notes show how to compile everything from source, but that's not necessary if you don't want to.
- It's also fine to mix and match binary packages with packages you build yourself.
- If you get binaries, you'll still need to do the configuration to tie it all together.
Install Apache 2.0.59
shell> cd /usr/local/src/apache-2.0.59
# Nothing too special. Enable shared-object support and
# use the prefork module recommended by php.net
shell> ./configure
--prefix=/usr/local/apache-2.0.59
--enable-so
--with-mpm=prefork
shell> make
shell> make install
Install PHP 4.4.4
shell> ./configure
--prefix=/usr/local/php-4.4.4
--with-apxs2=/usr/local/apache-2.0.59/bin/apxs
--enable-memory-limit
--with-mysql
shell> make
shell> make install
You might want other options. This is just a minimal set. I've already got a version of PHP running with my main web server, so I put this one in a different directory in /usr/lib/.
Configure Apache to server PHP4 content.
shell> vi /usr/local/apache-2.0.59/conf/httpd.conf # Load the PHP4 module. LoadModule php4_module modules/libphp4.so # Associate the three listed extensions with a PHP mime-type. AddType application/x-httpd-php .php .phtml .php3 # Turn up the error reporting in Apache since we're going to be # screwing around. Change this back to a higher level once # everything is working OK. LogLevel debug
Test the setup so far
Looks like everything is OK so far.
Install mod_fastcgi 2.4.2
shell> cd /usr/local/src/mod_fastcgi-2.4.2 Use the apxs program to compile *.c into a shared object called 'mod_fastcgi.so'. shell> /usr/local/apache-2.0.59/bin/apxs -o mod_fastcgi.so -c *.c Change to the directory where the .so ends up. shell> cd .libs Install the module. shell> /usr/local/apache-2.0.59/bin/apxs -i -n fastcgi mod_fastcgi.so
Note : mod_fastcgi 2.4.2 will not compile if you are running Apache 2.2. I found a patch
which will allow mod_fastcgi to compile with apxs for Apache 2.2.
http://httpd.apache.org/docs/2.0/programs/apxs.html
Setup work for mod_fastcgi
FastCGI needs a directory where it can create sockets for inter-process communication.
# Create the main fcgi-ipc directory, and 1 subdirectory # This can be anywhere. If your system automatically removes # things from /tmp, FastCGI will break. shell> mkdir -p /tmp/fcgi-ipc/dynamic # Make the directory world-accessible. shell> chmod -R 0777 /tmp/fcgi-ipc
Configure Apache and mod_fastcgi
shell> vi /usr/local/apache-2.0.59/conf/httpd.conf LoadModule modules/mod_fastcgi.so # Tell FastCGI where to create its IPC sockets. FastCgiIpcDir /tmp/fcgi_ipc/ # Tell Apache that .fcgi files should be handled by # FastCGI. 'fastcgi-script' is a handler that mod_fastcgi # registers in Apache. AddHandler fastcgi-script .fcgi
http://www.fastcgi.com/mod_fastcgi/docs/mod_fastcgi.html
http://www.fastcgi.com/mod_fastcgi/docs/mod_fastcgi.html#FastCgiIpcDir
Time to test again.
Looks like everything is still OK.
3 ways to access a FastCGI program
- FastCgiConfig (dynamic): PHP processes are started when first requested. FastCGI starts a process manager (fcgi-pm) which handles creating and destroying PHP processes.
- FastCgiServer (static) : PHP processes are started when Apache starts. Again, FastCGI also starts the process manager.
- FastCgiExternalServer (external) : FastCGI communicates the request to an
external program. No manager is started in this case.
- FastCGI assumes the external process is running, and you get a 500 error if it isn't.
- You can start php this way and bind it to an IP:port with the php -b argument.
- You need to implement your own manager to restart PHP periodically. Also look at the program cgi-fcgi that comes with the FastCGI devkit.
- Instructions on this are in /usr/local/src/php-5.1.5/sapi/cgi/README.FastCGI.
Install PHP 5.1.5
shell> cd /usr/local/src/php-5.1.5
shell> ./configure
--prefix=/usr/local/php5-fcgi --enable-fastcgi
--enable-memory-limit --with-mysql
# a security measure useful when the PHP binary
# will not be located in the webserver's document root.
--enable-discard-path
# Enable the security check for internal
# server redirects. You should use this if
#you are running the CGI version with Apache
--enable-force-cgi-redirect
shell> make
shell> make install
Configure Apache to pass PHP requests to FastCGI
shell> vi /usr/local/apache-2.0.59/conf/httpd.conf # Invent a new Apache handler, and tell Apache any .php5 # files should be handled by it. AddHandler php5-fcgi .php5 # Tell Apache that any requests for php5 content should be # directed to a script called php5.fcgi # php5.fcgi is covered in the next slide. Action php5-fcgi /php5.fcgi
Remember, anything called .fcgi is treated as a FastCGI program.
If you want .php files some directories to be PHP5, add this to Apache's configuration:
<Directory /usr/local/apache-2.0.59/htdocs/all5> AddHandler php5-fcgi .php </Directory>
So what is php5.fcgi?
It's a shell script that set a few environment variables and runs the PHP binary. Originally from this howto. README.FastCGI in the PHP source code has information on the 2 environment variables, and a few others. They are somewhat redundant with options available in FastCGI configurations. You can decide which approach you'd rather take.
#!/bin/sh PHP_FCGI_CHILDREN=4 export PHP_FCGI_CHILDREN PHP_FCGI_MAX_REQUESTS=5000 export PHP_FCGI_MAX_REQUESTS exec /usr/local/php5-fcgi/bin/php -c /etc/php5/apache2/php.ini
PHP_FCGI_CHILDREN : gives you better concurrency at the cost of more memory.
PHP_FCGI_MAX_REQUESTS : Kills a process after it has handled the given # of requests.
More on php5.fcgi setup
- Idle processes will be killed by FastCGI after the idle-timeout is reached. You'll see a warning in the Apache error log when this happens. This is normal as long as the exit status is 0.
- php5.fcgi must be executable by the webserver, and the directory its in must be +ExecCGI. (The PHP files themselves don't need to be executable.)
- If php5.fcgi is not executable, or if ExecCGI is not enabled, you'll get a 403:Forbidden error.
- You need a copy of php5.fcgi in the document root of every VirtualHost.
- You can add arguments to the 'exec' to tweak how php runs. You can, for example, have a separate php.ini file for every directory on your server.
- Not absolutely necessary to do it this way. You can copy the php binary into a cgi-bin directory if you're more comfortable with that.
So does it run?
Some phpinfo() screeshots
Links
Tutorials
- timdorr.com tutorial
- Howto forge tutorial
- Scott Hurring's tutorial
- fastcgi.com tutorial (specifically about PHP)
- Maven tutorial, also covers SuExec
- A post from some guy on WebHostingTalk
- Interesting thread from FastCGI archives about Apache configuration.
- Howto on running PHP as an external service.
- Howto on PHP5, FastCGI, suexec, and cpanel.