- [Instructor] The world of enterprise computing
has changed dramatically over the years
and the advent of virtualization
is one of those transformative changes.
It was only a few decades ago
that enterprise computing was confined
to the world of the data center and its mainframe.
Dozens of computing professionals
carefully tended to this very valuable resource
that served as the organization's electronic nerve center.
Then in the 1980s and 1990s,
the enterprise IT landscape shifted dramatically.
We moved away from the world of monolithic mainframes
to a new environment of client/server computing.
This shift brought tremendous benefits.
First, it put computing power right on the desktop
allowing users to perform many actions
directly on their own machines
without requiring mainframe access.
Centralized computing improved also
by allowing the use of dedicated servers
for specific functions.
It became much easier to maintain data centers
with discrete servers than tending to a cranky mainframe.
Over the past decade,
we've seen another shift in the computing landscape.
The client/server model has served us well,
but it's also resulted in wasted resources.
Data center managers realized that most of the time,
many of their servers were sitting idle
waiting for a future burst in activity.
That's not very efficient.
Around that same time,
virtualization technology became available
that allows many different virtual servers
to make use of the same underlying hardware.
This shared hardware platform makes it easy
to shift memory, storage, an processing power
to wherever it's needed at the time.
Virtualization platforms like VMware
and Microsoft Hyper-V make this possible.
At a high level,
virtualization platforms involve the use of a host machine
that actually has physical hardware.
That hardware then hosts several
or many virtual guest machines
that run operating systems of their own.
The host machine runs special software known as a hypervisor
to manage the guest virtual machines.
The hypervisor basically tricks each guest
into thinking that it's running on its own hardware
when in reality the guest is running on the shared hardware
of the host machine.
The operating system on each guest machine has no idea
that it's virtualized so software on that guest machine
can function in the same way as it would
on a physical server.
There are two different types of hypervisors.
In a type one hypervisor,
also known as a bare metal hypervisor,
the hypervisor runs directly on top of the hardware
and then hosts guest operating systems on top of that.
This is the most common form of virtualization
found in data centers.
In a type two hypervisor,
the physical machine actually runs
an operating system of its own
and the hypervisor runs as a program
on top of that operating system.
This type of virtualization is commonly used
on personal computers.
Common hypervisors used in this scenario
are virtual box and parallels.
From a security perspective,
virtualization introduces new concerns
around virtual machine isolation.
In a physical server environment,
security teams know that each server
runs on its own dedicated processor and memory resources
and that if an attacker manages to compromise the machine,
they will not have access to the processor and memory
used by other systems.
In a virtualized environment, this may not be the case
if the attacker is able to break out of
the virtualized guest operating system.
This type of attack is known as a VM escape attack.
Virtualization technology is designed
to enforce isolation strictly
and the providers of virtualization technology
take seriously any vulnerabilities
that might allow VM escape.
Security professionals working in virtualized environments
should pay particular attention to any security updates
that affect their virtualization platforms
and they should apply patches promptly.