Warning: session_start(): open(/var/cpanel/php/sessions/alt-php* failed: No such file or directory

Issue

The error is mainly found when the session directory of the version of PHP indicated in the error is not mounted in /etc/cagefs/cagefs.mp, for example: 

Warning: session_start(): open(/var/cpanel/php/sessions/alt-php56/sess_cqpk46rjk1r47liviubjka4ik3, O_RDWR) 
failed: No such file or directory

Environment

• CageFS
• CloudLinux OS

Solution

1. Check if the specified session is mounted in /etc/cagefs/cagefs.mp:

grep session /etc/cagefs/cagefs.mp

2. If this session is not on the list, edit the file /etc/cagefs/cagefs.mp with the following entries (our example with alt-php56):

@/var/cpanel/php/sessions/alt-php56,700 

3. And then perform:

cagefsctl --remount-all