The Best Settings for Configuring FastCGI (mod_fcgid)

Reading Time: 5 minutes

In our last tutorial, we showed you how to install Apache’s mod_fcgid and provided Linux scripts to assist in transitioning from mod_php. In this next section, we’ll be discussing how to configure a baseline setting for PHP optimization. Continue reading “The Best Settings for Configuring FastCGI (mod_fcgid)”

How to Install mod_fcgid on cPanel’s EasyApache 4 with CloudLinux

Reading Time: 6 minutes

When it comes to PHP execution, mod_fcgid (also called FCGI) is one of the heavyweight contenders. There are a few rival handlers, like PHP-FPM or mod_lsapi, which come close to matching its execution speed, but they generally leave something to be desired when it comes to fine-tuning and resource consumption. FCGI is built for speed and includes a myriad of Apache directives that can be leveraged for resource regulation.

This article will cover installing mod_fcgid followed by basic configuration in a separate article. The article applies to any cPanel servers running the following operating systems:

  • CloudLinux 6x/7x

The article will not cover EasyApache 3 (EA3). Due to the End-of-Fife (EOL) status of EA3, it is imperative that any systems running EA3 upgrade to EA4 as soon as possible. To avoid conflicts, upgrading to EA4 should be handled as an entirely separate procedure from installing mod_fcgid. If you need assistance with upgrading from EA3 to EA4, please feel free to contact our support team. If you’re running a Liquid Web Fully Managed cPanel server, our team will perform the entire upgrade procedure for you.

Expectations: Downtime & Performance

Downtime – Please plan ahead of time as this operation may cause downtime. While installing an Apache module and enabling a baseline configuration should only require an Apache restart, there may be unforeseen circumstances that require troubleshooting. This can lead to sites becoming unresponsive and/or slow.

Note
Always plan for more downtime than expected and always have a reversion plan. Allot extra time for troubleshooting, testing, and reverting all changes if necessary.

Performance – While FCGI provides superior PHP execution time, it is not a blanket fix for performance. For server optimization, there will be an adjustment period for configuration tweaking. This period can take hours to weeks as it must account for the unique caveats with the specific server hardware, software, traffic habits, and many other unpredictable variables.

Note
Optimization is an ongoing, perceptual process. There is no one-size-fits-all optimized configuration. Traffic & resource usages continually change over time on all servers. Periodic evaluation and configuration adjustment are necessary to stay ahead of the curve.

 

Installation of mod_fcgid

The following steps should be followed as close to the examples as possible. Things will vary slightly depending on CentOS/CloudLinux versions, and a few other factors. The article will denote the differences where they are expected.

Step 1) [su_highlight background="#3ac6eb"]Liquid Web Servers Only[/su_highlight] Disable Mod_Zeus & Other EA3 Modules

Older Liquid Web cPanel servers with EasyApache 3 who upgraded to EA4 may find residual configs on the system that can cause conflicts in the Apache configuration. This step will help make sure these older configs are disabled. The following sed one-liner will take care of disabling the inclusion line for these modules. These modules are stored in the /usr/local/lp/configs/httpd/conf.d/ directory. This directory is typically mentioned in the /etc/apache2/conf.d/includes/post_virtualhost_global.conf config file. The sed code looks for and comments out the specific include statement for this file.

sed -i -e 's/[^#]+\(Include [/]usr[/]local[/]lp[/]configs[/]httpd[/]\)/#\1/g' /etc/apache2/conf.d/includes/post_virtualhost_global.conf

To confirm the change, print the contents of the post_virtualhost_global.conf file using cat:

cat /etc/apache2/conf.d/includes/post_virtualhost_global.conf

The output should be blank or have a commented out inclusion line like below:

#Include /usr/local/lp/configs/httpd/conf.d/*.conf

Step 2) Disable Litespeed

FCGI is not compatible with Litespeed, which uses its own mod_lsapi module to process PHP using lsphp. Disabling Litespeed in this way does not remove it from the server; it merely enables Apache as the default web server.

/usr/local/lsws/admin/misc/cp_switch_ws.sh apache

Step 3) Install mod_fcgid

The following yum command will install the necessary module:

yum install ea-apache24-mod_fcgid -y

Once completed, confirm Apache has the fcgid_module loaded:

httpd -M | grep expires\|version\|fcgid

Example output:

fcgid_module (shared)

Step 4) [su_highlight background="#3ac6eb"]CloudLinux Only[/su_highlight] Configure CageFS Map for FCGI

The following snippet will create the necessary directories needed by mod_fcgid to execute correctly. It will then add those directory entries into the /etc/cagefs/cagefs.mp file, allowing user-level access to said directories from within their caged environment. It finally forces cagefs to remount all user directories for access to the new directory on all sites.

mkdir -p /var/run/mod_fcgid /usr/share/cagefs-skeleton/var/run/mod_fcgid /run/mod_fcgid
cp -p /etc/cagefs/cagefs.mp{,.lwbak.$(date +%F_%H%M%S)}
cat <<EOF>>/etc/cagefs/cagefs.mp
/var/run/mod_fcgid
/run/mod_fcgid
/usr/local/cpanel/cgi-sys/
EOF
cagefsctl -M

Step 5) [OPTIONAL] Remove Unnecessary Writable Permission

Due to security restrictions, any website files or directories with group-writable or other-writable permissions will be denied and a 500 Internal Server Error will be displayed. The following awk one-liner uses the find command to search all DocumentRoot directories configured on the server. It is advised to run this process in a screen session as it may take an hour or more depending on the size of the file system in question. The code takes care to use nice and ionice commands to run the process as a low priority so there will be minimal impact on server load or disk I/O. All changed files and their previous permissions are recorded in the /var/log/fixperms.log file.

Step 5a) Create & Attach to a Screen Session

screen -dmS fixperms; screen -x fixperms

Step 5b) Run the One-Liner

nice -n 15 ionice -c2 -n7 awk '/DocumentRoot/{DR[$NF]=$NF}END{for (e in DR) {x="find \""e"\" \\( -type f -or -type d \\) -and -perm /g+w,o+w -printf \"%M %y %m %p\\n\" -exec chmod g-w,o-w {} +"; while(x|getline) {print $0;print strftime("%F %T %Z"),$0 >> "/var/log/fixperms.log"} close(x)}}' /etc/apache2/conf/httpd.confExit screen by holding CTRL/CMD then pressing A, then D.

 

Step 6) [OPTIONAL] Disable mod_php Directives in .htaccess Files

Another common caveat when switching to FCGI is that any existing mod_php related directives inside any .htaccess file are not compatible with mod_fcgid and will cause the site to throw a 500 Internal Server Error. So these entries need to be located and disabled or removed.  The following awk one-liner checks all configured DocumentRoot directories for .htaccess files, and if they contain a php_value or php_admin_value entry, it will disable by commenting the line out. First, an in-place backup is created of the original file. The backup is named .htaccess.bak.YYYY-MM-DD_HHMMSS. All changed files and their previous permissions are logged in the /var/log/fixhtaccess.log file.

Step 6a) Create & Attach to a Screen Session

screen -dmS fixhtaccess; screen -x fixhtaccess

Step 6b) Run the One-Liner

nice -n 15 ionice -c2 -n7 awk '/DocumentRoot/{DR[$NF]=$NF}END{for (e in DR) { x="find "e" -name .htaccess -exec grep -iEl \"^([^#]*php_(admin_)?value)\" {} +"; s="sed -i.bak.$(date +%F_%H%M%S) \047s/^\\([^#]*php_\\(admin_\\)\\?value\\)/#\\1/gi\047 2>&1";
while(x|getline) {print $0; print s,$0; print strftime("%F %T %Z"),s,$0 >> "/var/log/fixhtaccess.log"; while(s" "$0|getline y) { print y; print strftime("%F %T %Z"),y >> "/var/log/fixhtaccess.log" } close(s" "$0)} close(x)}}' /etc/apache2/conf/httpd.conf

Step 7) Rebuild the Apache Config (Troubleshoot Any Errors)

The following command checks the system httpd.conf file for syntax error and if none are found, runs the cPanel httpd.conf rebuild script. Fix any syntax errors, until a clean rebuild is completed without error.

httpd -t && /scripts/rebuildhttpdconf

Step 8) [su_highlight background="#3ac6eb"]CloudLinux ONLY[/su_highlight] Setup PHP Selector

The PHP Selector feature of CloudLinux is only compatible with the inherit PHP versions in the cPanel MultiPHP Manager interface. All sites should be using the inherited version of PHP or PHP Selector will not function for that site. This only applies to CloudLinux servers.

Step 8a) Force All Sites to Use Inherited Version of PHP in MultiPHP Selector

The following command uses cPanel’s whmapi1 system to force all sites onto the inherited version of PHP in MultiPHP Manager.

/usr/sbin/whmapi1 php_get_vhost_versions | awk  -F'[: ]+' '$2~/vhost/{x="/usr/sbin/whmapi1 php_set_vhost_versions version=inherit vhost-0="$3;print x;system(x);close(x)}'

Step 8b) Disable MultiPHP Manager & MultiPHP INI Editor

The following uses the cPanel whmapi1 system to add MultiPHP Manager/INI Editor to the disabled features list.

/usr/sbin/whmapi1 update_featurelist featurelist=disabled multiphp=1 multiphp_ini_editor=1 ; /usr/sbin/whmapi1 update_featurelist featurelist=disabled multiphp_ini_editor=1

Step 9) Switch All PHP Handlers over to FCGI

The following will convert all installed PHP Handlers to using FCGI. These handlers are viewable through the Handlers tab of WHM’s MultiPHP Manager interface or by running the cPanel rebuild_phpconf script.

/usr/local/cpanel/bin/rebuild_phpconf --current | awk 'NR>1{x="/usr/local/cpanel/bin/rebuild_phpconf --"$1"=fcgi"; print x; system(x);
close(x)}'

To confirm the changes, run:

/usr/local/cpanel/bin/rebuild_phpconf --current

Example Output:

DEFAULT PHP: ea-php71
ea-php54 SAPI: fcgi
ea-php55 SAPI: fcgi
ea-php56 SAPI: fcgi
ea-php70 SAPI: fcgi
ea-php71 SAPI: fcgi
ea-php72 SAPI: fcgi

Step 10) Perform a Full Stop & Restart of Apache

The following script will stop Apache (gracefully if possible), and kill any unresponsive Apache & PHP processes before starting the Apache service again. It will also verify the Apache configuration syntax and will only perform the restart procedure if the syntax returns ok. This technique is handy as it is common for Apache processes to get stuck from time to time on busy servers.  This snippet deals with those scenarios after performing the humane stop request first.

httpd -t && (/scripts/restartsrv_apache stop; sleep 3; killall httpd php lsphp php-cgi; sleep 3; killall -9 httpd php lsphp php-cgi; /scripts/restartsrv_apache start) || echo Fix Apache Config and try again.

Note
Toss this snippet into an alias called apache_rescue which you can add to your ~/.bashrc for easy access to this code. Below is a one-liner that will create this alias for you and load the modified profile in your current session. Once this alias is installed, it will always be available on that server by typing apache_rescue.

cat <<'EOF'>>~/.bashrc && source ~/.bashrc
alias apache_rescue='httpd -t && (/scripts/restartsrv_apache stop; sleep 3; killall httpd php lsphp php-cgi; sleep 3; killall -9 httpd php lsphp php-cgi; /scripts/restartsrv_apache start) || echo Fix Apache Config and try again.'
EOF

This concludes our ten step process for installing mod_fcgid onto your cPanel system.  It’s recommended to adjust FCGI settings from their default settings. Tune into our next tutorial where we’ll be advising on how to optimize FCGI for various environments.

Install Multiple PHP Versions Using EasyApache 4

Reading Time: 8 minutes

EasyApache 4 installs, configures, updates, and validates your Apache, PHP and other services on your server. EasyApache 4 also supports multiple versions of PHP.  This allows you to assign different versions of PHP to each of your domains. There are great tools that have been implemented with EasyApache 4 that makes managing PHP versions simple. Two of these are the MultiPHP Manager and MultiPHP INI Editor. These can be found within the Web Host Manager, or “WHM” for short.  With the addition of these tools in cPanel/WHM, users can now complete most of these tasks from the Graphical User Interface. However, it is worth mentioning, attempting these tasks from the command line is recommended as we have seen better performance when compiling Apache builds.  

Continue reading “Install Multiple PHP Versions Using EasyApache 4”

Whitelisting in ModSecurity

Reading Time: 6 minutes

Broken down into two parts our article’s first section hits on “how to whitelist IPs or URIs,” for people who are somewhat familiar with ModSecurity but want to know further about the process. Our second section examines why we configure ModSecurity and how to prevent the security of the server from getting in the way of our work. If you have a Fully Managed Liquid Web server reach out to our Heroic Support team for assistance with whitelisting! Continue reading “Whitelisting in ModSecurity”

What is mod_deflate?

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How mod_deflate works

When a visitor accesses a website, a request is made to the web server for a specific kind of data. An example might be a home page of a site. Next, the web server locates that data and delivers it to the client who is requesting that data – basically back to the web browser.

In this example, the speed at which the home page loads can depend on a variety of factors. One of them could be how long it takes to find and deliver the data for that page. This is just one example.

Some of that data – such as javascript files, css files, and php files – can actually be compressed into smaller sizes before they are delivered back to the visiting client or browser at the smaller size. The visitor can now have a more optimized browsing experience.

This is where mod_deflate comes in.

Continue reading “What is mod_deflate?”

Using Passenger with cPanel on CentOS 7

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Phusion Passenger is a web application server that can run Ruby, Node.js, and Python applications on your webserver. It integrates with both Apache and Nginx to serve content to your visitors. Historically, this application was difficult to integrate with cPanel servers, which would combine the power of Ruby applications with the ease of management that cPanel provides, but recent advancements make setting up your Passenger module very simple. This easy walkthrough will show you how to add Passenger, Apache mod_passenger, and the supporting Ruby installation to cPanel. Continue reading “Using Passenger with cPanel on CentOS 7”

EasyApache 4 & CLI based PHP utilities

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With the release of EasyApache 4 in WHM 58 there are various changes to how PHP is managed. The most obvious being that EasyApache 4 brings support for installing multiple PHP versions alongside each other. However with multiple versions of PHP being installed on the server it’s easy to lose track of your command-line based PHP utilities and their PHP requirements. Continue reading “EasyApache 4 & CLI based PHP utilities”