VIRTUALIZATION SCHEMES

KAILA THORNTON

AARON HARTMAN

CS 455: Introduction to Distributed Systems

Computer Science Department, Colorado State University

Importance

Virtualization schemes are used in a variety of applications

Data Centers

Maintain support for legacy software

Increasing ability for load dispersion on servers

Allows generic hardware in distributed settings

Fault tolerance testing (contained environment)

Profound cost savings benefits

Problem

Hardware not being used efficiently

Previously a one-to-one relationship between hardware and OSs

Servers, in real world reports, average 5-12% utilization

Testing software on various platforms previously was very costly

Platform dependent applications required stand-alone hardware

Trade offs

Security

Joining two operating systems creates vulnerabilities where the layers meet

Modification of code

Para-virtualization requires kernel modification for direct hardware access

Performance hit

Native solutions are still faster than virtualized counterparts

Emulated hardware slow to catch up with latest offerings

Development constraints lead to later release of hardware support

approaches

Full Virtualization

OSs are on separate virtual machines unaware of each other

Hypervisor’s control hardware / virtualization interactions

Allows OS to be ran on hardware it was not designed for

Bare Metal vs. Native Virtualization

Bare Metal hypervisors are directly above the hardware

Native virtualization hypervisor is directly on top of the host OS

Para Virtualization

Guest OS communicates directly with Hypervisor

Increased performance

Requires code modification

Approaches cont.

Para-Virtualization cont.

Xen provides ability to dynamically instantiate virtualized OSs

Requires code modification

“Hypercalls” provide event support analogous to traps

Hardware Emulation

Provides a way to ‘trick’ an OS into thinking its running on different hardware

Requires no code modification

QEMU

Open source hardware emulator

Allows for unmodified host OSs on any architecture

Built in debugger

Portable dynamic code generator

Most target architectures of competing software offerings

Insights

Virtualization and Emulation have broad implications

Reduction of hardware

Cost efficiency

Better cluster utilization

More offerings to consumers

Complete automation of testing on multiple environments

Companies can rent shared hardware to customers without conflict

Future problems

Security

Increased adoption of virtualization in data centers creates vulnerabilities

Virtualization in mobile settings

Current offerings are too resource intensive for today’s devices

Increased use in Cloud services increases privacy concerns

Future solutions

VMWare NSX Software (announced 4th quarter 2013)

Virtualizes firewalls placing it at the hypervisor

System administrators will eventually be able to manage more systems

Easier access for consumers

Software as a service

Chromebook

Implications in Big Data

Amazon’s Elastic MapReduce and VMWare released virtualized Hadoop

Allows testing of a simulated cluster