Database Reference
In-Depth Information
redirected, the user can start contact the AppServer directly without going through
the AppLoaderBalancer during the current session. The
AppController
sit inside the
AppLoadBalancer is also in charge of monitoring the AppServers for growing and
shrinking as the AppScale deployments happen over the time.
There is no single cloud infrastructure provider has their data centers at all
possible locations throughout the world. As a result, all cloud application providers
currently have difficulty in meeting SLA expectations for all their customers. Hence,
it is logical that each would build bespoke SLA management tools to provide better
support for their specific needs. This kind of requirements often arises in enterprises
with global operations and applications such as Internet service, media hosting, and
Web 2.0 applications. This necessitates building technologies and algorithms for
seamless integration of cloud infrastructure service providers for provisioning of
services across different cloud providers.
2.6
Business Benefits of Cloud Computing
With cloud computing, organizations can consume shared computing and storage
resources rather than building, operating, and improving infrastructure on their
own. The speed of change in markets creates significant pressure on the enterprise
IT infrastructure to adapt and deliver. In principle, cloud computing enables
organizations to obtain a flexible and cost-effective IT infrastructure in much the
same way that national electric grids enable homes and organizations to plug
into a centrally managed, efficient, and cost-effective energy source. When freed
from creating their own electricity, organizations were able to focus on the core
competencies of their business and the needs of their customers. In particular, cloud
computing technologies have provided some clear business benefits for building
software applications. Examples of these benefits are:
1.
No upfront infrastructure investment
: Building a large-scale system may cost a
fortune to invest in real estate, hardware (racks, machines, routers, backup power
supplies), hardware management (power management, cooling), and operations
personnel. Because of the high upfront costs, it usually takes several rounds
of management approvals before the project could even get started. With cloud
computing, there is no fixed cost or startup cost to start your project.
2.
Just-in-time Infrastructure
: In the past, if your system got famous and your
infrastructure could not scale well at the right time, your application may became
a victim of its success. On the other hand, if you invested heavily and did not
get famous, your application became a victim of your failure. By deploying
applications in cloud environments, your application can smoothly scale as you
grow.
3.
More efficient resource utilization
: System administrators usually worry about
hardware procuring (when they run out of capacity) and better infrastructure
utilization (when they have excess and idle capacity). With cloud technology,
