Good. Now we have something in a layman's language.
Now to your questions:
> Not sure why virtualization and multi-tenancy should be conflicting.
Neither do I. My browser tracked what I have been writing and proposed
https://www.computerworld.com/article/2517005/data-center/multi-tenancy-in-the-cloud--why-it-matters.html. (I know, it is from 2010. Which is positive, there must be a follow up.)
;-\
> It all boils down to the question whether the Moodle stack is stateless.
>
> If it is, then there should be no problem...
Are you not familiar with Moodle? Simplified, its code, the $moodle directory, is read-only for the web-
server. But it needs write permissions on a second directory which we call $moodledata. This is unique for each Moodle instance. Moodle stores all sorts of things there, so delicate, and needs to be fast. And there is a third thing: where Moodle puts its session data. This can be configured, the parameter either in $moodle/config.php or in the
database, decides whether the session is stored in $moodledata or in the database.
> each request can be handled by any of the processor, if it is false and there is affiliation between a processor and a request, then all you can do is load balance per tenant, you cannot load balance the whole cluster.
>
> Being stateless incurs costs... (of restoring the state between calls) however this might be worth to achieve the optimization of the whole cluster.
Sorry, no idea what you are talking about. The dockerized people seem to have a language of their own, just like the Amazon Elastic Band group. Same thing with your other post
https://moodle.org/mod/forum/discuss.php?d=365847#p1475589. Well it has more problems. Do you write on a game console or something? What are the sentences? What are paragraphs, what are enumerations? Why the big space at the end? For the reply? I find the subject interesting, but the communication very difficult.