Database Reference
In-Depth Information
Platform as a Service
The final of the classic cloud computing layers to be discussed in this context is Platform as a Service (PaaS). This
layer is a hybrid between full access as it is granted with an instance in an IaaS environment, and the ready-made
web application available to you in the SaaS world. From the offerings available on the Internet, it appears as if PaaS
is mainly targeted at developers, and it is aimed at making deploying applications easier. In addition to the developer
focus, some PaaS providers have developed their own frameworks promising the user to deploy applications in very
little time without being a hardcore coder.
Most providers of PaaS will allow access based on an API (Application Programming Interface) to the deployment
environment. The benefit in such a scenario is again the limited cost of upfront development. A small startup
company does not have to pay licenses to access Enterprise-grade software to get started with the implementation.
The fee to be paid includes access to the hosted environment-specialist skill to maintain a few servers with databases
and web server is often not required immediately. Previously, before the advent of a PaaS offering, the start-up fee
presented substantial up-front cost before any revenue was generated.
The Public Cloud
When thinking about the Cloud as such, most users I spoke to immediately think about the public cloud. For example,
your webmail client's interface uses an external facing HTML 5 application hosted in a data center somewhere in the
world. For most use cases this is not a big deal. Users of webmail clients and other services to synchronize files with
multiple private computers do not worry where their date is stored. The security-conscious user thinks a bit differently
and installs software to encrypt traffic to and from the cloud, and maybe the data that has been permanently stored in
the cloud as well.
Commercial use of the public cloud requires a different approach. Many countries have very strict rules about
data protection and privacy. While this is a great democratic achievement for the citizen, it imposes barriers to the use
of the public cloud. If for example no personal data may be stored outside the country, then it is next to impossible to
legally make use of external data centers.
Additionally the Internet infrastructure becomes very important: while most users enjoy a lot of bandwidth
downstream, equal upstream capacity is either very expensive or simply not available. Anyone who uploaded data
over the Internet will notice that immediately. Also a failure of the Internet connection will cut off the users from the
service. Realistically speaking this should be a rare occurrence, but it can happen. Frequent travelers will know the
problem of being disconnected during the time on an airplane, and roaming fees while travelling abroad naturally
impose limits on bandwidth usage.
The Private Cloud
The private cloud takes the ideas already implemented outside the company's data center in the public cloud inside
the data center. There are many reasons for this: accessibility, connection quality, bandwidth, and security are just
a few to mention. By “private cloud” I refer to a cloud-like deployment of applications and services which are not
accessible to the public.
Private cloud is an oxymoron to the purist, and here is why. The Cloud Computing movement has advocated
the shift of paradigm from capital expenditure (capex) to operational expenditure (opex). As you saw before, using
for example Amazon's EC2 offering you don't need to invest upfront in dedicated hardware and storage (=capital
expenditure), but pay for when you use it (=operational expenditure). So when using the in-house data center, clearly
capex are not reduced.
When the benefits of automation, consolidation, and standards were discussed in this chapter, I implicitly
assumed that they were implemented locally, in the company's own, or alternatively outsourced, data center rather
than with a third party.
In many ways application deployment in the private cloud is easier, mainly because the security, regulation, and
other legal requirements are under tighter control. This of course can become a moot point if security is not properly
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