In my previous post I introduced what I consider to be the five key attributes of the cloud, but now we’re going to move into the main point of this series: defining the different clouds, public and private, then breaking down their differences. First up: What is a public cloud?
The “public” cloud is what users normally think of when they think of the cloud: Amazon, Rackspace, Nirvanix, Microsoft Azure. These are, by far, the biggest and most popular providers and, thanks to them, anyone with a credit card and five minutes can have instantaneous access to application resources. They’re open, accessible on the public network, and you get equal access no matter where you are – at work or at home. They are the public utilities of computing.
In most cases, you can drop the “public” qualifier and no one would be the wiser. The cloud is almost synonymous with the public cloud and, for what it’s worth, the inception and adoption of the public cloud is the reason we at Nasuni are sitting here right now. I don’t think the cloud could have gained such a foothold without the public, utility-like service providers.
The main attributes of the cloud – self-service, ease of use, scalability, speed/agility, and on-demand – weren’t its only key selling point. The fact that anyone could/can allocate and consume these resources is what transformed it into such a disruptive idea. The public cloud is cheap, easy and fast.
If those five core attributes I outlined are the main focus of the cloud, public clouds add several more that ultimately set it apart from the private cloud concept. These are:
Economy of Scale
This is basically the idea that the cost of something falls as more of it is used. In the case of the public cloud, the customer’s costs – your costs - fall as more people and companies adopt and leverage the technology. The nice thing is that the providers compete. When one cloud provider drops its prices, the others tend to follow. So, as Amazon’s adoption grows, the company reduces prices, and so do the rest of the providers. Consumers almost always win here.
The only way public cloud companies can make this work is with systems that inherently support multi-tenancy aggressively (they have to put as many users as they can in the fewest resources possible). Multi-tenancy allows any number of users or applications to leverage the resources exposed by the cloud at once.
Domain Knowledge
No one – except other vendors – assumes they have the same knowledge as Amazon or Google when it comes to running large-scale clusters of machines. Amazon, Google, Rackspace and Microsoft have years of experience maintaining large pools of virtualized CPU, operating systems and storage. That combined experience allows them to run cheaper, at a much, much larger scale, more reliably and more globally than most in-house IT firms even want to.
Externally Hosted
This is a massive benefit. These public utility clouds are globally accessible because these providers have already done massive, global rollouts of their systems in many, many data centers. Additionally, they deal with the power, the cooling, and the network infrastructure. Your organization has little to no capital expenditure. Your biggest concern is the bandwidth needed to leverage these resources.
Proven Infrastructure
Perhaps this is slightly redundant given the domain knowledge and external hosting already cited, but a coworker of mine once said: “We want to use the thing everyone else is using.” This isn’t a comment on hype. No one wants to follow the crowd off a cliff. Rather, it’s a reflection on the importance of stability, reliability and sustainability. A solid cloud service with a proven track record, such as Amazon or Rackspace, and hundreds of thousands of users – daily – has learned the hard lessons, and worked around or through them.
The public cloud brings a lot to the table. It’s enriching and empowering to end users, developers and companies. There’s a flip side of the cloud coin, though, and that’s the private cloud. So, what is a private cloud?
When I first heard the term private cloud, I shook my head, dismissing it just as I’d done with Amazon’s 2006 release of S3. The notion of a private cloud seemed insane, and completely against the idea of the cloud. With time, though, I started thinking that this term – and the larger concept – actually made a lot of sense.
Private clouds are virtualized computing resources hosted within the walls of a given company or entity (such as the military, or NASA). These resources have the same five core attributes as the larger cloud, but typically don’t share the additional ones outlined for the public cloud. So, private clouds offer self-service (simple APIs, a good interface), pay on demand, speed of provisioning, etc. They share the same soul as the public cloud.
Now, that’s fine. It’s got the same soul. But you – like I did – might be asking yourself why, given the added benefits of the public cloud, you would opt for something like this. Again, it boils down to a series of unique features:
Hosted by You
This feature – right here – is almost the antithesis of everything the public cloud stands for. But to some it is very appealing. Most IT people and larger organizations have already built out large-scale infrastructures at great cost. They’ve sunk money and manpower into the effort. They’ve paid for the infrastructure, and by hosting a cloud themselves they have far more control. They can see what data goes in, who does what, etc. It’s easy for them to control or push back on costly or needy individuals or groups within the organization. Their private cloud can be expanded or replaced at will. This could also be called “big-C Control” – and you can’t put a price on that when talking with larger companies.
Security
The public cloud is public. That’s a simple fact. The IP addresses - unless protected - are on a public network. Data stored in a public cloud is located on someone else’s machine. The cloud provider (the host) has access to all of this data and, if it’s not handled properly, data can be exposed during transfer and at rest. The private cloud brings this back within your walls. You control the network, the hardware, and the flow of information. You also guarantee physical security. For large, sensitive companies out there, this is the number one concern, and one of the fundamental reasons Nasuni exists (more on that later).
Customization
“You can’t beat custom-built.”. For large organizations with highly specialized needs, a customized deployment of either open source or for-pay private cloud software may be just the thing to bring the benefits of the cloud to your organization. The fact is that you won’t see custom deployments from public cloud providers any time soon. They need to serve the 90% - users and developers – not the 10% use case. You’re also self-reliant with private clouds. You’re a master of your own destiny.
Performance
This is a matter of perspective, but a selling point to many organizations. Amazon has massive pipes all over the world, so the latency between you and them is pretty low on average. Still, you cannot beat local LAN performance. Something hosted locally will always destroy something hosted on the public Internet.
Now that we have detailed the attributes and strengths of both the private cloud and the public cloud, we’ll take a break.
Next up, I’ll compare the two, contrasting the benefits of each (can the private cloud leverage economies of scale?), and hopefully help you and your organization make some sense of these important, but often confusing new trends.
Until then, if you have any thoughts or comments or questions, sound off below or send us a note at feedback@nasuni.com.