This document discusses virtualization techniques and cloud computing. It begins by defining virtualization as creating virtual versions of hardware platforms, operating systems, and other resources. Virtualization provides benefits like cost reduction, isolation, testing, and ease of duplication. The document then covers different virtualization types including full virtualization, OS-level virtualization, and hardware-assisted virtualization. The second part of the document defines cloud computing and discusses how it enables fast provisioning, easy scaling, and pay-as-you-go metering. It provides an overview of Amazon Web Services, including computing, storage, database and messaging services.

1. Virtualization Techniques
&
Cloud Computing
Brahim EL BOUDANI
This presentation is under creative commons BY-NC-SA license

2. What will talk about
•
Virtualization
–
–
Why do we use it?
–
Is it really a new technology?
–
•
What is it?
Virtualization Types
Cloud Computing
–
What is it?
–
Why to use it?
–
Is it mature and dependable? Should we use
it?
–
Example: Amazon Web Services

3. Virtualization
•
What is Virtualization?
•
refers the act of creating a virtual (rather
than actual) version of something, including
but not limited to a virtual computer
hardware platform, operating system (OS),
storage device, or computer network
resources.
•
Is it a new technology?
–
No, IBM started it in the 70's (or even
60's).

4. Why Virtualization?
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Cost Reduction.
•
Isolation and creating protected environment.
•
Testing and evaluation of OS, kernel, or an application.
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Teaching.
•
Ease of duplication.
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Relocation (and disaster recovery).
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Running Application not supported by the host.
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Green IT.
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… etc.

5. Virtualization Techniques
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Full Virtualization.
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OS-level Virtualization.
•
Partial Virtualization (Historical, not used).
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Paravirtualization.
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Hardware-assisted Virtualization.

6. Full Virtualization
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Concept: The host OS emulated a hardware
layer for each guest OS.
•
Pros: Stability, comptability, guest OS is not
patched.
•
Cons: resources, porfromance.

7. OS-Level Virtualization
•
Concept: Same OS for everyone (host &
guest), and isolation is only in the userland. If
you run `ps aux` in the host, you will see all
guests processes.
•
Pros: low overhead, highest performance.
•
Cons: isolation, stability.
•
Examples: FreeBSD Jails, Solaris
Containers, Virtuzzo/OpenVZ.

9. Paravirtualization
•
Concept: A thin layer (called the hypervisor, you can
think of it as a kernel more than an OS), interfaces the
hardware to all OS's (host and guest), Dom0 is called
”the privilged domain” which can issue commands to
the hypervisor.
•
If Dom0 crashed (not the hypervisor), the guest OS still
runs fine, anyway you won't be able to control the
hypervisor till you reboot.
•
The hypervisor provides API's to the DomU's kernels,
which are not actually real kernels, they only interface
these API's to the userland, not real kernels.

11. Paravirtualization Cont'd
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Pros:
–
–
Performance is very good (nothing can beat OSlevel virtualizatin in this matter).
–
•
Stability is very close to the hardware virtualization.
Overhead is very low (kernel level only, and not
even a complete kernel).
Cons:
–
–
Both host and guest kernels has to be patched.
–
•
Not easy to implement (it's getting better these
days).
Maintainability.
Example: Xen project by Linux

12. Hardware assisted Virtualization
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VirtualBox
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VM ware
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Xen
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Qemu
•
Virtual Iron

13. Hardware-assisted Virtualization
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Sometimes it's called accelerated
virtualization or HVM (Hardware Virtual
Machines).
•
Concept: Hardware provides support to run
instructions independently for each OS.
•
Implementation: IBM 370 (1972), Intel VT,
AMD-V, UltraSparc, and others.
•
Examples: linux KVM, Vmware fusion, M$
VirtualPC, Xen, Virtual Box.

14. Hardware-assisted Cont'd
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Pros:
–
–
Theoritically optimal performance.
–
•
Highly reduces (theoritically eleminates) the need to
patch the guest OS.
Great Stability.
Cons:
–
Hardware restrictions.
–
A “pure” hardware-assisted virtualization approach,
using entirely unmodified guest operating systems,
involves many VM traps, and thus high CPU overheads;
this limits scalability and the efficiency of server
consolidation. This performance hit can be mitigated by
the use of paravirtualized drivers; the combination has
been called “hybrid virtualization”.

15. Part Two : Cloud system

16. Cloud Computing
•
So What is Cloud Computing Anyway? Do you find
yourself saying "am I the only one that is confused
about this?"
•
Two openions about this:
Cloud is Not a technology
Cloud is a Pradigm Shift
It's just a mechanism of outsourcing
Internal infrastructure (IaaS), it just
didn't come up with new technologies.
It's a marketing hype, nothing more.
It's a total new technology shift to
utilizing new technologies in a more
usable and abstract way. It has
offered the core technologies in a
very practical way.
My Openion? Well those 2 openions are the same.. It's a marketing
hype that will drive the techies to make new technologies that didn't
exist before, like what always happens...

17. Cloud Computing Cont'd
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Are all clouds are public ones like AWS?
–
Of course not, there are private clouds, check
eucalyptus (or ubuntu enterprise cloud), it's an
open source (and free software, as speech & as
beer) software.
•
It's also a business hype, everybody is talking about it.
•
The most known public clouds are Amazon and
Rackspace clouds.
•
Everything is great, it's cheaper, more performant, and
sustainable... where's the trick?

18. Cloud Pros
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Very fast provisioning.
•
Easy scaling up/down.
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Virtually unlimited resources.
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Agility.
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Cost, on certain situations anyway.
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Metering, you pay as you go.

19. Bottom Line
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Cloud is good when you have large scale, variable
load application, and you need to minimize the cost.
•
Cloud is also good in application that are memory
intensive but not CPU intensive, e.g RoR
applications.
•
It should be suitable soon, this technology have the
potential but it just needs to get more mature.
•
If you are a system developer, it's a very good
chance to enter this hype now, cause later it will be
very complicated (if it's not already late).

20. AWS Overview
•
Now let's talk about AWS stack, we chose it cause it's one of
the most complicated clouds around.
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AWS is based on Xen Virtualization.
•
It contains the following services:
–
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SimpleDB, Relational DB Services (RDS): Database.
–
Simple Queue Service (SQS), Simple Notifications Service
(SNS): Messaging.
–
Simple Storage Service (S3): Storage.
–
Elastic Block Storage (EBS): Storage.
–
•
Elactic Computer Cloud (EC2): computing.
Others: like CloudFront, CloudWatch, AutoScaling, … etc.
The minimal stable is EC2 + EBS

21. EC2
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Computing instance, the harddisk is totally volatile if the
instance crashed (which happens, rarely but happens).
•
The smallest instance type is 1.7G RAM, 1 CPU
(1~1.2GHz), 32bit OS. The largest is 68.4 G RAM, 8 CPU
(3.25~3.9GHz), 64bit OS.
•
Very Obvious that CPU is the most costy part
•
2 identical instance with only difference in CPU (1 CPU of
1~1.2GHz Vs. 2CPUs of 2.5~3GHz), both are 1.7G RAM, 32
bit OS. The price difference is exactly double.

22. EBS & S3
•
They share that they are redaundant, reliable
storage. The maximum that happened before
is a blackout, but never a dataloss.
•
EBS can be mounted to a single EC2, which
is bad limitation.
•
S3 is to be accessed via http protocol, can be
a great help in serving static http files from
outside your servers.

23. Thank You