Cloud Computing

Cloud Computing a little intro:
Cloud computing is the next stage in evolution of the Internet. Cloud computing provides the means through which everything — from computing power to computing infrastructure, applications, business processes to personal collaboration — can be delivered to you as a service wherever and whenever you need.

The term "grid" is misinterpreted as a synonym for "cloud" as they both are made up with the addition of lots of computers connected. However they are two different things:



  
 Grid computing requires the use of software that can divide and farm out pieces of a program as one large system image to several thousand computers. One concern about grid is that if one piece of the software on a node fails, other pieces of the software on other nodes may fail. This is alleviated if that component has a failover component on another node, but problems can still arise if components rely on other pieces of software to accomplish one or more grid computing tasks. Large system images and associated hardware to operate and maintain them can contribute to large capital and operating expenses.


Cloud computing evolves from grid computing and provides on-demand resource provisioning. Grid computing may or may not be in the cloud depending on what type of users are using it. If the users are systems administrators and integrators, they care how things are maintained in the cloud. They upgrade, install, and virtualize servers and applications. If the users are consumers, they do not care how things are run in the system.

  



The difference between grid computing and cloud computing is hard to grasp because they are not always mutually exclusive. In fact, they are both used to economize computing by maximising existing resources.

However, the difference between the two lies in the way the tasks are computed in each respective environment. In a computational grid, one large job is divided into many small portions and executed on multiple machines. This characteristic is fundamental to a grid; not so in a cloud.

The computing cloud is intended to allow the user to avail of various services without investing in the underlying architecture.
Cloud services include the delivery of software, infrastructure, and storage over the Internet (either as separate components or a complete platform) based on user demand.





Cloud Computing having below landmarks

Public Cloud: IT resources offered as a service and shared across multiple organizations, managed by an external service provider
Private Cloud: IT resources dedicated to a single organization and offered on demand
Hybrid Cloud: a mix of private and public clouds managed as a single entity to extend capacity across clouds as needed

Cloud Models: Basically there are three areas which are known as cloud Models

  

Infrastructure as a Service (IaaS) is the delivery of computer hardware (servers,networking technology, storage, and data center space) as a service. It may also include the delivery of operating systems and virtualization technology to manage the resources. Benefits: makes the acquisition of hardware easier. Makes instant provisioning of hardware resources in a cheap way.

The Platform as a Service layer (Paas) offers development environments that IT organizations can use to create cloud-ready business applications. A PaaS is ultimately a contract between an hosted environment and user-provided extensions.

The Software as a Service (Iaas) layer offers purpose-built business applications In practical terms, this is the piece of cloud you are likely to build

You might wonder if it's possible that some services can be both defined as Platform and as Software: the answer is,of course yes! Take for example Facebook. We might define Facebook both as Platform where various services can be delivered and also as business applications (Facebook Api) which are developed by the end user.

Cloud security
cloud security must display six different attributes:
1. On-Demand Elastic Services

Security needs to be delivered as a service rather than as a set of products siloed within physical appliances. Like other cloud services, it needs to be delivered ‘on demand’ to protect data and projects when and where protection is needed.

2. Programmable Infrastructure

The security services that are applied across the cloud must be open to being programmed. With programmable security infrastructure, the services should be accessible using RESTful APIs that are programming language and framework independent.

3. Logical Security Policies

As security services are deployed in virtualized data centers and then private clouds, security policies need to be cut away from physical infrastructure and related to logical rather than physical attributes. By removing static security policies (associated with static attributes) the security assessments will be delivered quicker as well.

4. Adaptive Trust Zones

By creating trust zones or logical groups of workloads a better and more efficient security can be delivered.This is in contrast to a security infrastructure where policies are applied on a VM-machine by VM-machine basis.

5. Configurable Security Policy Management

You should be able to configure security levels as your applications move from on-premise to private clouds. Software controls need to be maintained when they are virtualized, the separation of duties assigned to the software should also be maintained.

6. ‘Federatable’ Policies

Though there are no established standards at the moment, it would be required that as private clouds will be applied incrementally, security polices would be applicable not only to private clouds, but also to the remaining infrastructure, both virtualized and physical, and would be intelligently able to cooperate.

References:
http://arstechnica.com/business/news/2009/11/the-cloud-a-short-introduction.ars/
http://bimeanalytics.com/cloud-computing/cloud-computing-care-2/
http://www.computerweekly.com/Articles/2010/01/12/235782/Top-five-cloud-computing-security-issues.htm
http://www.cmswire.com/cms/information-management/6-security-must-haves-for-cloud-computing-009171.php

 Article2

The Pros and Cons of Public, Private and Hybrid Clouds

Have you heard of the "private cloud" or the "hybrid cloud"?

The public cloud

In a nutshell, the public cloud is generally the most well-known and straightforward type of cloud computing. Public commodity cloud providers typically offer convenience — it's easy for enterprises and developers to set up, use and access the public cloud. Additionally, scalability is often a driving factor for businesses utilizing the public cloud. However, this type of cloud is not without risks.
Here's a brief breakdown of some of the main characteristics of the public cloud:

• Easy to use: Some developers may favor the public cloud (at least in the U.S.) due to its ease of access. Generally, the public cloud operates at a pretty fast speed, which is also alluring to some enterprises.
• Typically a pay-per-use model (cost-effective): Often, public clouds operate on an elastic pay-as-you-go model, so users only need to pay for what they use — some versions of public cloud are even free but price increases when larger workloads are migrated to the cloud.
• Operated by a third party: The public cloud isn't specific to a single business, person or enterprise; it is constructed with shared resources and operated by third-party providers.
• Flexible: Public clouds allow users to easily add or drop capacity, and are typically accessible from any Internet-connected device — users don't need to jump through many hurdles in order to access.
• Can be unreliable: Public cloud outages have made headlines in recent weeks, leading to headaches for users.
• Less secure: Particularly outside of the U.S. where data sovereignty comes into play (where your data is stored and who may have access to it), the public cloud often has a lower level of security and may be more susceptible to hacks. Some public cloud providers also reserve the right to shift data around from one region to another without notifying the user -– which may cause issues, legal and otherwise, for a company with strict data security policies.

The private cloud

For businesses concerned about knowing exactly where their data is stored and having complete control over it — and who, ultimately, has access — the private cloud provides a higher degree of peace of mind. Additionally, private clouds may be the best option for companies that must jump through a lot of regulatory hurdles or handle sensitive data, or for companies concerned over their own intellectual property being hosted on the public cloud.
Managed private clouds are one specific form of this type of cloud computing: This service refers to clouds that, though specific to an individual business, receive some assistance (such as operating service monitoring and patching) from a third party. This allows for a company to select the custom cloud model that fits its needs while leveraging secure third-party help for maintenance
Here are the main features of private cloud computing:

• Organization-specific: Private clouds are developed specifically for one organization or enterprise; unlike the public cloud, they aren't shared among many users.
• More control and reliability: Private cloud services and infrastructure are maintained onsite, or in a privately hosted environment such as a third-party data center. This gives an enterprise the utmost control over access — IT can know where information is deployed and can keep an eye on the boundaries that surround that data. Additionally, managed private clouds allow for strong service level agreements, which can increase reliability.
• Customizable: IT can customize storage and networking components so that the cloud is a perfect fit for the specific organization and its needs.
• More costly (arguably): Proponents of public cloud computing often tout its cost-effectiveness as one of the primary advantages. While private cloud may rack up costs due to increased management responsibilities and smaller economies of scale, it's worth weighing the risks/costs of security.
• Requires IT expertise: Some companies may not have the infrastructure to completely build out and manage a custom private cloud within their own IT department -– it can require a good deal of up-keep. In these cases, a managed private cloud may be a viable option.

The hybrid cloud

The hybrid cloud allows for a "mix and match" approach, enabling enterprises and savvy CIOs the ability to pick and choose various elements from either the public cloud or private cloud -– or a combination of the two — that make the most sense for their particular company. For example, a company could host its ecommerce website — complete with customer credit card information — on a private cloud, but could also host its non-sensitive material (such as marketing collateral, etc.) on the public cloud.
Typically, the hybrid cloud provides a balance of convenience and security — and in fact, experts predict that 2015 will see a huge rise in the number of enterprises using hybrid cloud services. Enterprise cloud providers, often advocate a hybrid cloud approach, focused on a using the right destination for the right application that makes sense for individual business needs.
Here's an overview:

• Flexible and scalable: Since the hybrid cloud, as its name suggests, employs facets of both private and public cloud services, enterprises have the ability to mix and match for the ideal balance of cost and security.
• Cost effective: Businesses can take advantage of the cost-effectiveness of public cloud computing, while also enjoying the security of a private cloud.
• Becoming widely popular: More and more enterprises are adopting this type of model.

Ultimately, hybrid clouds look to be a promising solution for the future