Where on earth are OLS wordpress Vhost PHP session files going?

Hi. Recent convert to the OLS world, currently running an official Wordpress OLS stack via provided instance via GCP marketplace (in GCP obviously).

Everything about this stack is brilliant, but in my efforts to using this base instance to build an auto-scaling cluster - I'm tearing my hair out trying to understand where PHP session state files are stored for the wordpress Vhost.

I've successfully configured the OLS admin php.ini to a custom (NFS mounted) location and can see the sess_* files written (and error in the log file when path not present). But trying to do the same for the wordpress Vhost simply does not work. To make matters worse, despite ltracing, stracing, 'find'ing my entire server I cannot find where the wordpress vhost and it's associated PHP processes are storing session files, despite manually overriding the php.ini file at /usr/local/lsws/lsphp73/etc/php/7.3/litespeed.

Bafflingly - when I do alter the above path, a phpinfo() run from that Vhost (inside the docroot) shows my custom path for session.save_path present and correct - yet no session files ever turn up. Despite all of this - wp-admin sessions persist just fine on a single server.

Help me OLS Jedi - you're my only hope (for sanity)!

(Many thanks in advance)


It is always a good idea to create the phpinfo.php page to check. If "session.save_path" is set, then session will be saved to the defined location. If not, then default is /tmp/.