It’s the beginning of the New Year and as we reflect on the past years, I feel compelled to write this article to clarify what the Cloud actually is. Over the course of the next few months, I will attempt to take you through the evolution of Cloud computing from the past to the present and what the future holds.
A friend once visited me at work and looked at our Server room and asked me why we still had servers if we were into cloud computing. She felt that Cloud means no more hardware and everything just magically happens! I smiled and attempted to explain why we still needed physical servers and storage, but I could tell she was not convinced. She must have wondered what type of second rate cloud provider still needs servers. This brought it home to me that many of us still do not really understand what cloud computing is.
Firstly let us be clear that Cloud is not Virtualization, however virtualization is the building blocks of the cloud. Confused? Before I attempt to explain cloud computing and virtualization, there are some basic concepts you will need to understand.
So here they are:
- A Host is a physical server
- A guest is a Virtual Server, which runs a physical server
- A Hypervisor is the layer of software that abstracts the resources of the physical server and makes them available to the virtual servers.
- Each virtual server has its own operating system and applications and is self-contained.
- Each Virtual server running on the Hypervisor of the Physical server is given a portion of the physical servers Memory, Networking, Storage and CPU (compute) to use.
- Cloud computing is a form of utility computing.
- There are 3 main types of cloud computing namely: Private, Public and Hybrid.
Now you are wondering what Cloud has to do with utility. Well let me explain. We all use Electricity or Gas in our homes, however very few of us own Electricity or Gas power stations. In fact many of us have no idea how the electricity and gas we consume is produced. We pay for it and we expect it to be available when we need it. In essence that is what Cloud computing is. It is the abstraction of computing, storage, Networking and security resources from the user into a consumable service that can be bought like a utility. Not all cloud products are for sale, many are free public cloud services like Gmail, Hotmail, iCloud, DropBox to mention a few. What makes it cloud is how it is consumed.
When you have a cloud model, you no longer own the servers or storage your applications run on. You outsource that to a 3rd party and then consume those resources on a monthly or annual subscription basis. You pay for what you use and no more. You no longer need to worry about buying hardware or software licenses since you are now just a user.
In the following articles I will explain the different types of cloud computing there is and its evolution. Before I leave you, I feel we should discuss virtualization and its history.
In the traditional configuration, you would typically have a Server and on the Server you would install an Operating system like Windows or Linux and then on top of the operating system you would install your Applications and Database. In most cases the Server would also have some Storage (Disk) in it that would be used by the operating system and applications. In larger environments the Storage (Disk) would be in a Storage Area Network (SAN) or could be on Network Attached Storage (NAS). In 1998 VMware™ was the first company to successfully virtualize Microsoft™ Windows on the x86 server. x86 is the processor architecture that runs in your typical Windows and Linux servers. This meant that we could now run several servers virtually on a single physical server or host. These servers are called Guests. This helped many organizations save costs. Instead of having to buy one server per application, they could now have several applications safely running on several virtual servers on a single physical server. Since then Microsoft (Hyper-V) and Citrix have both released their own Server Virtualization products to compete with VMware.
Over the last 10 to 15 years many organizations have gone through a virtualization phase in order to save on costs, power and physical space in the data centers. Conservative estimates say that over 50% of all servers are now virtualized and it is believed that by 2016 it will have reached over 80%.
A natural evolution in the pyramid of needs is now we have virtualized our servers and saved $x dollars, what is next. Now comes the promise of the cloud. But before you get excited there is still a lot to understand about virtualization before we delve into the cloud.
I will leave you for now to digest what you have read until the next part.