Which software runs and manages virtual machines?

Yes, virtualization software, also known as a hypervisor, allows one computer or server to host multiple operating systems. It enables the hardware resources of a single computer—processors, memory, storage and more—to be divided into multiple virtual computers, commonly called virtual machines (VMs). Each VM runs its own operating system (OS) and behaves like an independent computer, even though it is running on just a portion of the actual underlying computer hardware.

All the virtual machine instances are called Instance Resource.

The term describing a secure individual, private cloud-computing model hosted within a public cloud is Virtual Private Cloud (VPC).

A VPC is a cloud model that offers the benefits of a private cloud using public cloud resources. VPC uses isolated environments within public clouds and allows organizations to run their workloads independently from other users.

Preemptible VMs can offer many advantages over a standard Compute Engine VM. One reason customers choose preemptible VMs is to reduce cost. Customers can save up to 80% more with Preemptible VMs than with regular Compute Engine instances. Another reason is that PVMs function well for testing, rapid batch processes, and fault-tolerant systems

Customers with fluctuating or unpredictability in their usage patterns benefit from cloud resources like virtual machines that are billed by the second. These users can reduce costs and save money by only paying for the time a resource is used.