Virtualization

Summary

• Hypervisors
• Connecting the Dots
• Full Virtualization
• Para Virtualization

Hypervisors

Operating System of Operating Systems = Hypervisor (or VMM)

Two Types:

• Native/Baremetal
  • Hypervisor is running on hardware
• Hosted
  • Hypervisor runs on top of host OS
  • VMWare Workstation
  • VirtualBox

Native Hypervisors offer best performance

Connecting the Dots

• IBM VM 370 (70’s)
• Microkernels (late 80’s & 90’s)
• Extensibility of OS (90’s)
• SimOS (90’s)
• Xen & VMWare (early 2000’s)

Full Virtualization

Leave guest OS untouched

• Even though guest OS doesn’t have the same level of privilege that it’s expecting
  • Privilege escalation attempts are trapped in hypervisor, which emulates intended functionality

Para Virtualization

Modify source code to make it away that it is a guest

As far as applications are concerned, nothing is changed because the upper interfaces are left intact

Only less than 2% of code needs to be changed

• Proved by Xen