Python/NodeJS application shows the "Invalid command 'PassengerAppRoot'" error

Issue

 A Python or NodeJS app responds with the following error:

Invalid command 'PassengerAppRoot', perhaps misspelled or defined by a module not included in the server configuration.

Environment

• CloudLinux OS 6/7/8
• cPanel
• DirectAdmin
• Python selector
• NodeJS selector

Solution

Try to install the Passenger module: 

For cPanel:

# yum install ea-ruby27-mod_passenger

For DirectAdmin:

# yum install alt-mod-passenger

And update CageFS after that:

# cagefsctl --force-update && cagefsctl -M

Cause

Missing Passenger module.

Useful links

https://docs.cloudlinux.com/cloudlinux_os_components/#requirements