How to Solve a Problem in a Clustered Environment?

There is no way i can cater for e one, for example. Applicus still doesn't offer any clustering, whatever. So it's single server. I'm banging my head against the wall for a long time how to approach it. And someone just told me, he you just need cubenetes. What do you mean by that? There is millions of er tasttat can solve with cubeanetis. Even those that usually don't exist in the first place.