Following are the types of Virtual Machine based isolation :
a. Process Virtual Machines:
- Focus: Isolating individual processes or groups of processes.
- Example: Running different applications in separate virtual environments.
- Guarantee: Isolation is ensured by a runtime component, preventing direct access to resources.
b. System Virtual Machines (Hypervisor Virtual Machines):
- Focus: Replicating the entire underlying platform, allowing full operating systems to run within it.
- Example: Running multiple operating systems on a single physical machine.
- Guarantee: The hypervisor (virtual machine monitor) mediates all hardware resource accesses, ensuring isolation.
c. Hosted Virtual Machines:
- Focus: Built on top of an existing operating system (host), making the virtual machine look like an application.
- Example: Using software like VMware GSX Server where virtual machines run as applications on top of the host OS.
- Guarantee: Isolation is similar to the hypervisor approach, but the virtual machine monitor doesn’t run at the highest privilege.
d. Hardware Virtual Machines:
- Focus: Utilizing virtualization features provided by hardware (processor or I/O).
- Example: Taking advantage of hardware-assisted virtualization for improved performance.
- Guarantee: Better isolation and security compared to software-based approaches due to direct support from the hardware.