Blog #4 : Compute

The world of IT infrastructure is essentially made up of storage and compute resources plumbed together with networking equipment. In this post I am going to talk about the compute element of that mix and how public Clouds have revolutionized the provisioning and use of this vital component.

So what are these “compute resources” then? What I mean by this is the things that actually do all the hard work of computing. In the world of traditional IT these would be physical computers sitting in a big room full of cables and air conditioning (often known as a data centre <https://en.wikipedia.org/wiki/Data_center>). These computers would all have their own CPU’s, memory and disks and would be running operating system software (such as Unix/Linux or Microsoft Window ). These computers would normally be referred to as “servers” (since they provide services to other computers) and one piece of physical hardware would equate to one server.

A revolution then occurred which meant that many servers could run on one piece of physical hardware. This revolution was called virtualization <https://en.wikipedia.org/wiki/Virtualization> and it allowed data centres to be transformed – with fewer physical computers,less power and air conditioning was needed and the provisioning of new servers became a lot more flexible. In the past, if a new server was required then you would have to wait until a physical computer could be purchased, delivered and then set up. With virtualised servers it became possible to provision a new server on an existing virtual host server (and easily get rid of it again once it was no longer needed). Even so there were still limits – the virtual hosts only had a finite amount of memory and disk space available.

The birth of the public Cloud 

Then the public Cloud came into existence and heralded another transformation in the world of servers. Services such as Amazon Web Services <https://aws.amazon.com/> and Microsoft Azure now allow you to create virtual servers in their data centres. These data centres are vast and have near unlimited capacity to host virtual machines. This kind of service is often known as “Infrastructure as a Service <http://www.gartner.com/it-glossary/infrastructure-as-a-service-iaas/>” and allows virtual machines to be created in minutes to your specifications. Additionally, you typically only pay for them for the period in which you actually use them. This increase in flexibility provides many benefits including the ability to have powerful servers available with no up-front costs at all – a great boon for start-up type companies, but useful for anyone commencing a new project. It also allows companies to have backup servers in case of a disaster, at very low cost.

To give an example, Amazon Web Services (AWS) provide Cloud based virtual machines via their Elastic Compute Cloud EC2 <https://aws.amazon.com/ec2/> service. The EC2 service has a simple web interface which allows new instances to be created very easily and quickly. There are a large range of different instance types including ones optimised for storage or compute performance. On AWS you pay for EC2 instances by the hour and you can get discount on the cost by reserving them for one or three years.

Virtual machines are one of the cornerstones of Cloud computing and the flexibility, pricing model and convenience that they provide are one of the main reasons why the Cloud is permanently changing the IT landscape.

Cloud is about how you do computing, not where you do computing.

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