Cloud computing by some accounts is the best thing that ever happened to the world of IT and businesses. It does not matter whether you are a mom-and-pop shop or a fortune 10 company, you have a "cloud strategy." If you are vendor, you have a cloud solution. If you are business, you want your applications on the cloud.
What we call cloud computing has been around for a number of years now. It has a new name, new slogan, but it's been here all along. If you think about it, grid computing, HPC or High-thruput computing have been used and deployed for years. Internal cloud is nothing more than a Grid infrastructure. What are we talking about here then? What the types and classifiers for different types of cloud.
Overview and Landscape of Cloud
What are our options here? Too many people use too many different acronyms and phrases, but there are generally speaking 4 different classes of infrastructures that are now classified as cloud:
Option 1: Internal Datacenter; all dedicated resources
Option 2: External Datacenter; all dedicated resources
Option 3: External Datacenter; shared access by the public
Option 4: Internal Datacenter; shared access by the public
Figure 1 below better demonstrates these classifiers.
Figure 1: What are your options for Cloud Computing?
An internal private cloud is nothing more than a Grid or a virtualized environment that you have in your own datacenter. You own everything; the network, the machines, the real-estate, etc. It is your facility. High Performance Computing, Grid, distributed computing, server farms, etc, are instances of this model.
Many organizations have started an external private cloud. This is the same thing as above but you are using someone else's datacenter. You pay for the usage, like the way you pay rent. There is nothing more to it. There is a dedicated line from you facility to theirs; you pick the hardware, the software, etc.
External public, some would argue, is the "true" cloud. This is a model that you pay per use. You access using the Internet making the quality of service or QoS is unpredictable. The usage is shared in that many users have access and use the same infrastructure. This shared access is why public clouds are perceived to have a lower cost of ownership (more on this in a later article).
Internal public does not really make sense other than if you are a vendor - i.e. an Infrastructure as a Service provider. From a user perspective, an IaaS is either an external private or external public depending on their level of service.
You have options to chose from; what's wrong with that? Whether or not you are able to take advantage of these options is up to you. Look at Figure 2; migrating to one of the external options is not as easy as some make it sound.
Figure 2: Is External Public Cloud for you?
The biggest concern for external public cloud is around security and Quality of Service (QoS). Accessing resources via the public internet does not guarantee a static QoS throughout the usage. Obviously, sharing resources with others also does not bode well with legal and security folks either. These two items could make or break your cloud strategy (another overloaded term that I will get into shortly).
The good news is that if you are small enough, you won't have any of these problems - but for larger organizations, external public clouds pose a risk that is not desirable under any circumstances.
The biggest question today is which one of these options makes sense for you and your organization?
Pick One, Pick All
Which one of the three options should you choose for your business?
1. Internal and private
2. External and private
3. External and public
The forth option does not really make sense, so we will leave that out for the moment. This is where the controversy begins. My view is that you need to have a private infrastructure if your utilization or usage of your infrastructure is high. How high? I would say that if you are over 60% utilized, you should be using a private or dedicated infrastructure. This is solely to the fact that cost of cloud is actually much higher than if you owned your own infrastructure.
If you fall below this high-water mark, you should consider utilizing the public infrastructure. As you can see, this is not a hard set role in that your decision is not final. Based on where you are in your business efficiency, you can and should go back and forth on usage.
Figure 3: Cloud Usage as a function of Utilization
Where do we go from here?
Computing is a commodity. You naturally want to get the cheapest and the fastest computing infrastructure for your buck. There are options out there with the adoption of cloud and we covered the landscape in this article. We have a lot more to cover on this topic, but the ground is laid down for us to move on to other topics. Keep reading.
Tags: Grid, High Performance Computing, HPC, Messaging, Scheduling, Utility Computing, SoftModule