How to organize the smooth operation of several sites on one VPS?

Question

LAMP

Hello.
Bought a small VPS, installed Vesta with all the necessary software.
There are several Internet sites (php) on VPS on different CMS, attendance is also different.
Suppose that on one of the sites, due to a programmer's mistake, a situation has arisen when a PHP script is ready to use all available RAM, or sends an infinite number of requests to the database, or something like that.
How to make sure that such errors do not lead to the inoperability of all sites at once? Those. is there any software that allows you to track resource consumption within a single VPS and, if necessary, respond to such situations? Send a notification to the email, "block" the work of the problem site.

Answer 1

cgroups