CLOUD
STRATEGY
Cloud computing is a model for enabling
ubiquitous, convenient, on-demand network access to a shared pool of
configurable computing resources (e.g., networks, servers, storage,
applications, and services) that can be rapidly provisioned and released with
minimal management effort or service provider interaction. This cloud model is
composed of five essential characteristics, three service models, and four
deployment models. Cloud Computing came
about with the convergence of technologies. Of course, you need hardware.
Relatively inexpensive servers and storage makes data centers possible.
Increased availability of high-speed Internet connections means these data
centers can be located where it is most economical.
Of course, a data center alone does not
constiture Cloud Computing. Cloud Computing is realized through the Cloud
Computing Stack. The Cloud Computing Stack organizes the hardware/software of a
data center into various service layers. These layers are organized into Cloud Computing
Categories.
Virtual machines/servers can be specified in the
Cloud. A given Cloud may contain multiple servers/machines supporting various
software/services. Connections to these services are made using Web Services that are the basis of application program
interfaces (APIs) commonly used in
Cloud Computing.
Payment for Cloud Computing services is usually
on some incremental basis. In other words, you pay for only what you use. This
works for organization of most any size. It is possible that for smaller
organization, Cloud Computing will allow the use of software that would
normally be prohibitively expensive if the organization had to buy it and
install it on their own server. For very small organizations, it might be
possible to find Cloud Computing services that are free for low levels of
usage.
Blurring of Services
It is possible to assemble a service-oriented
architecture (SOA) that uses services from multiple Cloud providers along with
services provided by systems internal to an organization. This results in a
blurring of where the services actually reside. In fact, most often it does not
matter where they reside for functionality. Location of services are often
dictated governance issues such legal or security concerns, as
opposed to technical issues.
Web
Services and Cloud Computing
The following Venn diagram
illustrates the relationships among Web Services, service-oriented architecture
(SOA), and Cloud Computing. Web Services encapsulates Cloud Computing in this
diagram because Cloud Computing uses Web Services for connections (you might
find exceptions, but they are rare). It is possible, however, to use Web
Services in situations other than Cloud Computing. Such use of Web Services may
be part of a service-oriented architecture, but it may not. Web Services could
be simply be a connection. Finally, it is possible to have a service-oriented
architecture and not use Web Services for connections.
Service-Oriented
Architecture (SOA) and Cloud Computing
The page expands on the Service-Oriented Architecture (SOA)
Definition page to show that the same
architecture can be used with Cloud Computing. A service provider can be in a
Cloud or not in a Cloud and a service-oriented architecture (SAO) can involve
any combination of Clouds and Non-Clouds as is illustrated in the figure below.
Types
of Clouds in Cloud Computing
Basic types of Clouds in Cloud
Computing:
1. Private Cloud
A
Private Cloud is implemented using a dedicated data center infrastructure of
hardware and software that is used privately by an organization. The data
center can be on-premises or off-premises. It is not shared with another
organization. If the data center is shared, that is a Virtual Private Cloud.
2. Public Cloud
A
Public Cloud is implemented using a shared data center infrastructure of
hardware and software that is shared by multiple organizations. The data center
is off-premises.
3. Hybrid Cloud
A
Hybrid Cloud is any combination of Clouds. It could be a Private Cloud and one
or more Public Clouds. Similarly it could be a Virtual Private Cloud and one or
more Public Clouds. It is, however, more than just multiple Clouds. There needs
to be resources shared among the Clouds. An example is Cloud Bursting.
Variations on the basic types of Clouds in Cloud
Computing:
1. Virtual Private
Cloud
A
Virtual Private Cloud is implemented using a shared data center infrastructure
of hardware and software. The data center is most likely off-premises. It is
shared with multiple organizations. If the data center is not shared, that is a
Private Cloud.
2. Community Cloud
A
Community Cloud can be a Private Cloud , Virtual
Private Cloud , Public Cloud , or Hybrid Cloud. A
Community Cloud is designed to meet the needs of a community. Such communities
involve people or organization that have shared interests. This includes
industrial groups, research groups, standards groups, and so on. So, a
Community Cloud is not so much a type of Cloud as it is a way to look at how
Clouds could be used. The data center supporting the Community Cloud could be
one of the member organizations or it could be in a location separate from all
member organizations.
Categories of Cloud Providers
The
figure below illustrates the relationship of Infrastructure as a Service
(IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) in the
Cloud Computing stack. For a discussion on each type of Cloud provider, see:
Software
as a Service (SaaS)
Software
as a Service (SaaS) is what most people mean when they say "the
Cloud." SaaS provides a complete software solution. This software could be
email management, calendaring, enterprise resouce planning (ERP), customer
relationship management (CRM), documentation management, and so on. The easiest
way to think about SaaS is that it is some type of standard software package
that can be used on demand and is paid for by subscription, by use, by
advertising, or by sharing information (such as email addresses) of users
Platform
as a Service (PaaS)
Platform
as a Service (PaaS) is the next step down from Software as a Service (SaaS) in
the Cloud Computing Stack. Instead of ready-made applications or services, PaaS
provides the platform for developing such applications and services. Here you
find various development tools and such things as database management
systems , enterprise services buses
, application servers , business intelligence, and so on that
could be used to support the applications and services developed
Infrastructure
as a Service (IaaS)
Infrastructure
as a Service (IaaS) is the next step down from Platform as a Service (PaaS) and
two steps down from Software as a Service (SaaS) in the Cloud Computing Stack.
Instead of ready-made applications or services, developement tools, databases,
etc., IaaS provides the underlying operating systems, security, networking, and
servers for developing such applications, services, and for deploying
development tools, databases, etc.
Cloud
Computing Governance
This
is a brief summary of some Cloud Computing governance issues
Technical
Issues
Determine
how the Cloud Provider::
§ Supports change management
§ Provides for high-availability
§ Provides for redundancy and failover (if any)
§ Provides for security related to the Internet
§ Provides for physical security
Legal
Issues
It is
important to determine what needs to be in a contract with your Cloud provider.
Things to consider:
§ Service standards to be maintained
§ Retention of rights to your data
§ Legal jurisdiction where the data center is located
§ Privacy laws where the data center is located
§ Liability of data breaches
§ Policies and procedures related to providing digital
forensics data in the event of any legal dispute, cyber attack, or data breach.
§ Notification of changes when they occur at the data center
§ Disaster recovery
§ Remedies for various possible problems
§ Details for what occurs at the beginning and end of the
contract period
Business
Issues
Your
business relationship with a Cloud provider should involve:
§ The Cloud provider's reputation
§ Financial stability of the Cloud provider
§ The length of time the Cloud provider has been in business
§ Management practices for the data center
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