9/26/2011 1 CSE 501 Monday, September 26, 2011 Kevin Cleary – [email protected]What is Virtualization? What are the different types of virtualization. Practical Uses Popular virtualization products Demo Question, answer, discussion Can mean many things: Application virtualization Desktop (client) virtualization Memory virtualization (beginnings of cloud computing) Hardware virtualization Storage virtualization Software simulation of hardware resources Simulated resources can execute operating systems and programs like real physical machines. Software run on virtual machines is isolated from the underlying hardware resources.
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Practical Uses Popular virtualization products Question ... · Disadvantages: Reliance on sound network connections Initial deployments can be very complex and costly Virtual desktop
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The software or firmware that creates a virtual machine is called a Hypervisor or Virtual Machine Monitor.
Hypervisors can provide different levels of virtualization:
Guest software needs to be specifically modified or “virtual machine aware” to run in a para-virtualization environment .
Partial - Some of the target environment
is simulated
Full - Almost complete simulation of the actual hardware
Para - hardware environment is not simulated; guest
software is executed in own isolated
domains
Slowest Fastest
Increase the utilization of costly hardware resources such as CPU and memory.
More granular control of hardware resources
A virtual machine can be more easily controlled and inspected from outside than a physical one, and its configuration is more flexible. This makes virtual machines useful for:
Kernel Development
Teaching operating system courses
A new virtual machine can be provisioned as needed without the need for an up-front hardware purchase.
A virtual machine can easily be relocated from one physical machine to another as needed.
Copy a virtual machine with demonstration software to a laptop
Migrate from faulty to backup hardware
Disaster Recovery purposes Site Colocation
Virtual machine images can be easily cloned and re-used.
Ability to “Snapshot” known good configurations
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Lower cost (money and time) of deploying services Less hardware needed
More efficient use of hardware resources
Easy to develop and test systems and software
An error inside a virtual machine does not harm the host system
“Risky” tasks can be isolated in a virtual machine Web Browsing!
Needing to run an application not natively supported by the host OS.
Ex: Mac User’s needing to run Windows Apps.
Evaluate an alternate OS. Ex: Windows users giving Ubuntu a test drive.
Server Virtualization Running multiple virtual servers on a single physical server.
Duplicating environments: A way of distributing pre-configured environments to other users.
When is it not advantageous to virtualize a machine?
When applications require a lot of CPU or memory resources such as a compute server.
When applications generate a lot of disk I/O.
When some type of service is already performing a virtualization task
Ex: Citrix or Sunray Services
When there is a high network link utilization that cannot be bound to a particular NIC
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Hardware-assisted virtualization requires explicit support in the host CPU, which is not available on all x86/x86_64 processors
Virtualization often exacts performance penalties resources required to run the hypervisor
reduced performance on the virtual machine compared to running native on the physical machine.
A guest operating system will run faster on the “bare CPU”.
Upfront costs are not cheap! More expensive hardware is needed in some cases
Robust setups may need additional storage and expensive hypervisor software
Duo booting requires more of a change to the hard disk. Resizing of volumes and partitioning can sometimes cause problems that result in data loss.
Sometimes files are not shared between the OSs (although this seems to be getting better).
Virtual disk images expand on demand and make more efficient use of drive space.
Ultimately one OS goes unused more often, which means more time goes by until patches and anti virus definitions can be applied.
Virtualization gives more flexibility on 2nd, 3rd, Nth operating system setups.
At least some type of duo core CPU with some type of virtualization extension support. Available for both Intel and AMD.
Intel virtualization (VT-x)
AMD virtualization
(AMD-V)
Support for this may need
to be enabled in the BIOS.
At least 2-4 gigabytes of RAM
If you want to virtualize a 64 bit OS you will need a 64 bit CPU.
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Interacting with a desktop which is being simulated on a separate physical machine.
Separate physical machine are capable of accommodating many users.
Advantages: Distribution of pre-configured desktop significantly reduces hardware and utility costs.
Easier to backup data
Easier to distribute applications
Disadvantages: Reliance on sound network connections
Initial deployments can be very complex and costly
Virtual desktop infrastructure (VDI), can be thought as a more advanced form of hardware virtualization:
Users interact with a client program rather than directly interacting with a host computer via a keyboard, mouse and monitor connected to it
User interacts with the host computer over a network connection using another desktop computer or a mobile device.
Client programs: My Virtual Lab:
http://ubit.buffalo.edu/software/virtual/
Session virtualization, allows multiple users to connect and log into a shared but powerful computer over a network and use it simultaneously. This is very similar to timesharing!
Client based programs: Oracle Virtual Desktop Connector:
Public or Private Clouds? Upfront cost is reduced in a public cloud model
Capital expenditure is converted to operational expenditure
Lower barriers to entry
Pricing on a utility computing basis is fine-grained
Both private and public clouds offer hardware elasticity via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis near real-time.
Public or Private Clouds? With Public Clouds a greater importance is placed on understanding and negotiating service level agreements (SLAs).
This means replacing IT staff with lawyers
Access times may decrease to resources in a public cloud model.
Usually internal network speeds are faster than internet connections.
Public or Private Clouds? Which is more secure?
Concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels.
Sometimes IAAS providers are able to devote more resources to solving security issues that many customers cannot afford.
Complexity of security is greatly increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users.
Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.
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Parallels: http://www.parallels.com/
Vmware: http://www.vmware.com/ For CSE student licensing information see: https://wiki.cse.buffalo.edu/services/content/vmware-academic-program
VirtualBox: http://www.virtualbox.org/
Windows Hyper-V: http://www.microsoft.com/windowsserver2008/en/us/hyperv-main.aspx
Xen: http://www.xen.org/
Eucalyptus IAAS: http://www.eucalyptus.com/
Amazon EC2: http://aws.amazon.com/ec2/
For more details on demoed products see: http://aws.amazon.com/ec2/