The phrase 'cloud computing' has been used heavily within the IT industry for many years now and across many different sectors, such as retail and finance, and it's often referred to simply as the cloud. Now, cloud computing is a rapidly growing technology, and the adoption of this is a key strategy for many organisations and there's a very good reason for this. It changes the landscape of how many companies and organisations operate on a huge scale with significant business technical advantages and benefits that can't be ignored. The growth of cloud computing has been on an exponential growth rate for many years. So, what is it? Well, put simply, cloud computing is a remote virtual pool of on-demand shared resources including compute, storage, network, and many more services that can be rapidly deployed at scale. Now, there may be a couple of terms within this definition that are new to you or not too clear, such as virtual or compute. Now, don't worry, I'm going to break these down as we go through this video, after which I shall give you the definition again and you should be able to fully understand this concept.

Before fully understanding cloud computing, we must be aware of some existing technology that it's based upon, that being virtualisation. Virtualisation maximises the power of cloud computing and without virtualisation, it just would not be possible. So, what's virtualisation? In essence, it allows multiple virtual machines each running a separate operating system and applications installed on one physical server. These virtual machines, or VMs, all run at the same time without being aware of each others' existence whilst sharing the underlying hardware resources of the single physical server. This sharing of hardware resources is a key element of understanding virtualisation and uses a component called a hypervisor. This hypervisor is a piece of software used to create the virtualised environment, allowing for multiple VMs to be installed on the same host. When installed, it sits logically between the physical hardware and the virtual machines and creates a shared pool of virtual hardware resources for each of them to access. All VMs stored installed on the host see the hardware as they normally would. However, any request to the hardware goes via the hypervisor which handles the access ensuring the hardware resources are shared between all VMs as needed.

Now, there are obvious benefits of virtualisation which include reduced capital expenditure as less hardware is required as you can have multiple VMs installed on one host. Reduced operating cost as there is less hardware, less space, power, cooling (ph 02.40) is required for your data centre. And less space is required to house your server hardware in your data centre or server farm, which is where your servers and network equipment resides. This optimisation of resourcing and equipment in the cloud environment means everyone that uses the infrastructure, vendors and consumers, can benefit from this approach. Just a quick note before we leave the topic of virtualisation, a VM within the public cloud is sometimes referred to as an instance. This term is very vendor-specific, but it refers to the same object as a virtual machine. When discussing resources within cloud computing it won't be long before you come across the terms compute, storage, or network resource. It's a good idea to have a clear distinction between what each of these are and it will certainly help you going forward when identifying what services you want to move to the cloud, should you decide to do so.

So, compute. Compute objects provide the brains to process your workloads, including what's required to process and run requests from applications and services. In the classic environment comparison, you can think of hardware devices with CPUs and RAM, typically servers, and how they work in a classic environment. Compute resources in the cloud are comparable to these. Storage resources simply allow you to save your data across a shared environment. Any object that allows you to save your data in the cloud is classed as a storage resource.

Now, again, in the classic environment comparison, in a typical environment, these would be seen as your server hard disk or your network-attached storage, NAS, which is far-level shared storage accessed over the network and your high-speed storage area network, your SAN, used for block-level shared storage. Network resources provide a connectivity allowing all other resources, such as compute and storage, to communicate with each other. In a classic environment comparison, you would find hardware such as routers to route traffic between networks, switches which provide the backbone of your network connectivity allowing hosts to talk to one another, and firewalls to allow or deny traffic into the environment.

So, now, if we go back to our basic definition of cloud computing given earlier of, 'Cloud computing is a remote virtual pool of on-demand shared resources including compute, storage, network, and many more services that can rapidly be deployed at scale', you should now have a clearer understanding of what this means. The red section refers to virtualisation and the blue section refers to some of the typical resource types available with cloud computing that we just discussed.

What is Cloud Computing?

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