Hello,
How is realized isolation of user resources from each other?
All keyhelp user accounts (=clients) are true system user accounts with their own home directories.
PHP runs via php-fpm
-> each PHP script ist called in context of the current user,
they are restricted to their home directories by php's open_basedir restriction.
-> php settings can be set individually to each user.
Currently there are still some weaknesses concerning SSH access.
You should give SSH access only to trusted keyhelp users, because SSH-Jail is not implemented yet.
And what are minimal system requirements for KeyHelp?
Operating System: Ubuntu 12.04 / Ubuntu 14.04 / Ubuntu 16.04 / Debian 8
The most limiting factor is possibly be the amount of available RAM.
KeyHelp installs some other daemons, for example an av-scanner which could demand a bigger part of your RAM.
(This av-scanner can be switched off, in case).
Though i have no data concerning the lowest possible RAM, i can tell you that we use KeyHelp for systems with 1 GB RAM without problems.