Page 65 - DCAP609_CLOUD_COMPUTING

Cloud Computing

Notes The traditional model of software distribution, in which software is purchased for and installed
on personal computers, is sometimes referred to as software as a product.

Figure 5.1: Levels of Abstraction in Cloud Computing

Source: http://www.silverlighthack.com/image.axd?picture=2011%2F2%2FCloudServiceTerms.png
5.1.2 Concerns

The Cloud Computing model is not without concerns, as others have noted, and we consider the
following as primary:

Failure of Monocultures

The uptime of Cloud Computing based solutions is an advantage, when compared to businesses
running their own infrastructure, but often overlooked is the co-occurrence of downtime in
vendor-driven monocultures. The use of globally decentralized data centers for vendor Clouds
minimizes failure, aiding its adoption.
The basic problem with a monoculture is that it’s all vulnerable to the same attack. There are
certain risks in networked computer systems. If everyone is using the same operating system or
the same applications software or the same networking protocol, and a security vulnerability is
discovered in that OS or software or protocol, a single exploit can affect everyone.
When a cloud fails, all organizations dependent on the Cloud cripple. In a computing monoculture,
all of the nodes/servers are identical and share the same vulnerabilities. So any attack that can
take over a single node can take over the entire cloud. This was illustrated by the Amazon (S3)
Cloud outage, which disabled several other dependent businesses.
In addition, by adding a layer of software to coordinate the individual computers, the cloud
creates more complexity, which means more opportunities for something to go wrong and
create a vulnerability by mistake.

Example: Hypervisors, the software that manages the multi-tasking and virtualization
process at the heart of cloud computing, add additional complexity to cloud computing nodes.
Convenience vs. Control

The growing popularity of Cloud Computing comes from its convenience, but also brings
vendor control, an issue of ever-increasing concern. Cloud computing is a classic example of the

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