Additional PHP versions with multi-server setup

I have a pair of servers built on Ubuntu 18.04 many years ago and incrementally upgraded to 24.04. I occasionally have an issue on the slave where the exec line of /var/www/php-fcgi-scripts/<something>/.php-fcgi-starter is missing an executable name so site does not work. Usually I fix this by copying the file over from the master and then it works again. But today I decided that it's time to investigate the root cause and fix it properly.
It looks like whenever I have added PHP versions in the past, I was supposed to create the PHP version entries for each server from the master management interface. I am attempting to correct this now but I am only offered the master server as an option when adding, so cannot create entries for the slave.
I can see both servers in Server Services and both servers are Web servers.
Both servers are in Server Config. No obvious differences with web configuration there.
Both servers are present in IP Addresses, but the slave server name is missing [IP address is correct].
Not sure where else to look.

 

"Mirror" is a good description here, both servers are supposed to be identical. So explicit PHP version entries per-server are not necessary in "mirror" mode? But how do I know if that is how I set it up? Unfortunately, trying to remember what I did in 2019 is asking the impossible
The servers have been generally fine over the years, only issue is that occasionally Unison gets stuck or MySQL replication breaks but they're simple enough to fix.

 

Yes it does. So the issue is not about configuring the additional versions per-server.
What else would explain why .php-fcgi-starter is not created properly?

 

Any other ideas?
If I make a trivial change, I see it says it re-writes the file, but no errors emitted by the writing process:

Code:

Tue Jan 21 05:58:02 PM UTC 2025 PHP Warning:  Undefined variable $custom_fastcgi_php_ini_dir in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1569 
Tue Jan 21 05:58:02 PM UTC 2025 PHP Deprecated:  substr(): Passing null to parameter #1 ($string) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1569 
Tue Jan 21 05:58:02 PM UTC 2025 PHP Warning:  Undefined variable $custom_fastcgi_php_ini_dir in /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php on line 1569
Tue Jan 21 05:58:02 PM UTC 2025 21.01.2025-17:58 - DEBUG [system.inc:2436] - safe_exec cmd: chattr -i '/var/www/php-fcgi-scripts/web55/.php-fcgi-starter' - return code: 0
Tue Jan 21 05:58:02 PM UTC 2025 21.01.2025-17:58 - DEBUG [apache2 plugin.inc:1602] - Creating fastcgi starter script: /var/www/php-fcgi-scripts/web55/.php-fcgi-starter
Tue Jan 21 05:58:02 PM UTC 2025 21.01.2025-17:58 - DEBUG [system.inc:2436] - safe_exec cmd: chattr +i '/var/www/php-fcgi-scripts/web55/.php-fcgi-starter' - return code: 0

But perhaps that Undefined variable $custom_fastcgi_php_ini_dir is significant?

 

Still having this issue. Even if I fix it and then chattr +i /var/www/php-fcgi-scripts/web55/.php-fcgi-starter it will be overwritten later.

 

They are most definitely not. Otherwise you wouldn't have this problem.

Have you compared /usr/local/ispconfig/server/conf/php-fcgi-starter.master on both servers?
Or maybe you have your own custom version in /usr/local/ispconfig/server/conf-custom?
I expect you'll find differences.
If not here then somewhere else on your servers.

 

Identical.

They are mostly the same with a few 'empty.dir' files in there. The two servers have a /usr/local/ispconfig/server/conf-custom/vhost.conf.master-2024-11-<slightly different times> file in there, but those two files are identical except the name.

How can I debug , or manually trigger, the .php-fcgi-starter generation process?