Virtualisation
Splits one physical server into many virtual machines.
What It Is
A hypervisor splits one physical server into many virtual machines. Each virtual machine gets its own share of the processors, memory, disks and network, and runs its own operating system as if it had the machine to itself.
VMware ESXi installs straight onto the hardware, with no ordinary operating system beneath it. Hyper-V is the same kind of hypervisor. Once it is turned on, it runs beneath Windows, which manages the other virtual machines from above. In the cloud, the provider runs the hypervisor and you rent virtual machines on it.
Keeping virtual machines apart is the hypervisor's job. The wall is thicker than the one between containers, because each virtual machine has its own kernel, but a flaw in the hypervisor breaks it.
- App
- Framework
- Web Server
- Runtime
- Containers
- OS
- Hypervisor
- Firmware
- Hardware
- Data
On This Layer
These are the technologies on the Virtualisation layer that this topic covers. Open one to see what it runs on, how to spot it and what a flaw in it reaches.
How Far a Flaw Reaches
A flaw in the hypervisor reaches every virtual machine on that host, whatever operating system each one runs. That is why ransomware crews have gone after ESXi, since one host can hold a whole estate.