What virtualization is used by cloud and famous hosting providers?

Question

Virtualization

What is used as virtualization, for example, a virtual machine for $ 5 with 512 GB of RAM and an SSD on aws or digitalocean.
Do they use their own solutions or are they publicly available?
Maybe someone knows the nuances of hosting and "cloud" hosting.

Answer 1

digital ocean and linode and vscale use kvm, which redhat bought at one time and plugged into the vanilla Linux kernel
aws, which is also amazon, uses xen because at the time when it all started it seemed that xen would drive everyone, xen was for everyone, including by default in redhat and everything was gradually moving towards its inclusion in the vanilla core, but then, in my opinion, citrix bought it, and in response, redhat bought kvm, and they abruptly changed roles, xen from a leader became a dying technology, and kvm from a sluggish project turned into a leader and entered core.
in general, if you are just a hosting provider, it is pointless for you to develop your own virtualization, since you earn on something completely different.

Answer 2

aws

Answer 3

kvm in the majority, xen is good too