Dumitrache.net

In a previous article I told you about a free web based control panel for managing a web hosting company. Today I am going to tell you how to fix the most common error that occurs while running ispCP:  ”500 Server Error”.

Disclaimer:  Apply these settings at your own risk! I strongly suggest backing up your apache and ispcp configuration files before following the directions stated in this article.

There are several causes for this error. In most cases, this happens when your Apache web server tries to serve certain PHP scripts and fails because of a malfunction of the components required to execute the PHP scripts. When you install ispCP, it automatically configures your Apache web server to run the PHP interpreter via FCGID or FastCGI (it is recommanded that you leave it run via FCGID). When a request for PHP script is received, Apache links itself to a FCGID process. If no such processes are running, it creates one and links to it. After that, it commands FCGID to run PHP and execute the web script. So basically, the scheme of things is this:

User Request for PHP script -> Apache ->FCGID -> PHP: script.php.

It is important to know that, once created, a FCGID process will not terminate after it serves the first script. It remains started and will handle future requests from Apache, even multiple requests at the same time. It will eventually terminate after a number of served requests or after a defined time. Also, multilple FCGID processes can be started, each serving multiple requests. These numbers can be configured.

Cause of the error

One cause for this error is the improper configuration of FCGID which exists or fails before PHP finished parsing the requested web script. The Apache web server then returns the error 500, also known as Internal Server Error.

There is generally a 40 second limit for which an FCGID process will execute a particular PHP script. After that time passes, even if PHP has not finished its job, the process will terminate causing the error in Apache. This happens when PHP tries to parse a web script that takes longer to execute. No matter what execution limit you set in php.ini, if it’s larger then 40 seconds, it will be ignored.

My approach to this problem

I will explain how to fix this issue for websites that are already added in your ispCP panel. In the end, I will explain how to apply to correct settings to future websites that you will add.

First, you can find FCGID related settings in multiple configuration files but not all settings are applyed. PHP generally does its process management internally and ignores your FCGID settings. It does that badly. With the default configuration, you may experience some other problems such as too many FCGID processes that forget to “die” and sapp your memory. You need to disable PHP’s internal process management.

Step 1 – disable PHP’s FCGI process management

Go to /var/www/fcgi/yourdomain.com/

Edit the file php5-fcgi-starter and comment (prefix with #) the setting that have _FCGI_ in their names.

Note that all settings are individual for each domain. All configurations that are treated in this article are local. To apply these settings to all your future web sites you will have to edit ispCP’s template files that are used to generate the configuration files for every domain.

Step 2 – Global FCGI settings from Apache

All Apache related settings are ussually found at /etc/apache2

/etc/apache2/mods-enabled contains links to the configuration files of the modules that will be loaded by Apache. All the configuration files linked from this directory will be parsed but that doesn’t mean that all settings will be applyed. Like I said, the settings are individual for each VirtualHost (for each domain that you add) .

Edit /etc/apache2/mods-enabled/fcgid_ispcp.conf and set higher timeouts. Here is a page that explains these settings.

Configure this file according to your needs. Here’s how my file looks like:

<IfModule mod_fcgid.c>

AddHandler fcgid-script .php .php5

SocketPath /var/lib/apache2/fcgid/sock

IPCConnectTimeout 900

IdleTimeout 600

IdleScanInterval 120

ProcessLifeTime 900

MaxProcessCount 200

DefaultMinClassProcessCount 1

DefaultMaxClassProcessCount 10

IPCCommTimeout 900

BusyTimeout 300

BusyScanInterval 320

ErrorScanInterval 3

MaxRequestsPerProcess 500

ZombieScanInterval 3

</IfModule>

Now, the problem: These settings will be parsed but will not apply to your web sites (yourdomain.com) because these are defined as VirtualHost’s and global settings are ignored in these directives.

Step 3 – Force Apache to apply the above settings

The file /etc/apache2/sites-available/ispcp.conf contains all the VirtualHosts (domains) defined by ispCP. To apply the global FCGID settings to yourdomain.com, you must edit this file.

Open it and search

# httpd [yourdomain.com] dmn entry BEGIN

This is where the VirtualHost directive for yourdomain.com begins. Within this VirtualHost, search

<IfModule mod_fcgid.c>