My Article to FOSSUser - "Ubuntu on Cloud" Part 5

In 2004 Amazon adopted a formula. If your systems are big, assume decoupling has been also done. The decoupled sections should communicate; at least some messages basically has to be passed or interchanged, in order to get a productive output from the system. Amazon’s solution for this is queuing. Amazon thought this will be the simplest and first-in-first-out solution for communicating. SQS is what Amazon named it. By using Simple Queue Service, according what AWS says, “Developers can move their data in between the decoupled or distributed components of their applications that perform different tasks without any message loses or requiring each component to be available always”. One interesting attribute of SQS is that you can rely on the queue as a buffer between your components; well this will increase the elasticity.

In every application, what we have as a huge draw-back is the storage capacity. Actually what we need is an infinite-like storage capacity. To fix this problem Amazon came up with the solution, that is Amazon Simple Storage Service or S3 was released in 2006, just two years after the release of SQS. S3 allows you to store 5 terabytes of data with unlimited number of objects within. S3 as a service is covered by a service level agreement (SLA) helped the industry to fully-adopt the concept. As statistics say that, in only two years, S3 grew to store 10 billion objects. In early 2010, AWS reported to store 102 billion objects in S3.
People thought that S3 is the perfect solution to be placed because it resolved the storage issue. But still Amazon thought that S3 is not sufficient to decouple the big system into small components. In the same year 2006, Amazon released another limited beta model called Elastic Cloud Compute or EC2, which was the logical piece which was missing in the puzzle. Because through the decoupling Amazon was expecting strict SOA implementation. Amazon wanted every small team of an organization not only to build its own infrastructure, but also for developers to operate their applications themselves. This thought rooted a new service model which we call that as IaaS or HaaS. EC2 turned computing upside down. AWS used XEN virtualization to create a whole new cloud category.
Now let we take a look at virtualization and its functionalities in the cloud.

One of the most notable character of cloud computing is scalability. The key technology with enables scalability is Virtualization. Virtualization is in simple terms, one physical machine takes multiple roles, so one single machine acts as multiple machines. Virtualization, in its broadest sense, is the emulation of one of more workstations/servers within a single physical computer. The concept of virtualization is not limited to simulation of entire machines, there are many, each differs upon its functionality. One of these, a very commonly used in almost all machines nowadays, that’s virtual memory.

Although the physical locations of data may be scattered across a computer’s RAM and Hard Drive, the process of virtual memory makes it appear that the data is stored contiguously and in order.

RAID (Redundant Array of Independent Disks) is also a form of virtualization along with disk partitioning, processor virtualization and many other virtualization techniques. Virtualization allows the simulation of hardware through software. But for this occurrence, there should be some virtualization software installed in your physical hardware. VMware is well-known virtualization software, most users using it globally. There are other softwares also available in the market.  VMware is very much capable of stimulating an x86 based hardware resources, in order to create a fully functional virtual machine. After the installation of VMware, you can selectively install the OS you wanted and other associated softwares on the newly created virtual machine simply. Multiple virtual machines also can be created, but each as different entity. This entity method will cut the interference between each virtual machine in order to ensure that every VM is working separately.

The following figure 4 and 5 will express what if not there’s no virtualization and what is good if there is virtualization.

  

                                 Figure5

 Figure 4


          Continued in Part 6 
          http://imthefortune7.blogspot.com/2012/04/my-article-to-fossuser-ubuntu-on-cloud_4385.html