Cisco UK & Ireland Blog

Cloud: Public, Private, or Hybrid?

March 23, 2015

I’ve been told by the blog team that this post definitely falls under the ‘technical’ category (or to use their real language ‘requires coffee to comprehend’ category). Which is actually a good thing as there is no point in skimming the details when it comes to your infrastructure!

So you’ve been warned!

After several years of hype, organisations are finally deploying cloud. The question is: which type of cloud? This article focuses on IaaS/PaaS (infrastructure as a service/platform as a service) as opposed to SaaS (software as a service). I define private cloud as being on-premise; public cloud being Amazon Web Services, Microsoft Azure, Google Compute Engine, or other similar offering; and hybrid being a mix of the two.  


Let’s take a quick look at why an organisation would choose public cloud. If you’re a start-up business, then choosing public cloud makes a lot of sense. There’s no up-front capital investment, you only pay for what you use, and you can expand capacity extremely easily. If you’re an enterprise business with existing infrastructure, then it’s a little more difficult to work out. The factors are likely to be: cost, security, compliance, data sovereignty, and performance. Let’s go through some of those in a bit more detail…

Cost – There’s a general perception that public cloud is low cost, and I’m not going to debate that at length here. All I will say is that I’ve had several enterprise customers tell me that they’ve tried out public cloud and found it to be more expensive than the cost for them to do it on-premise. I’m sure this varies enormously between organisations, depending on how they are using public cloud, but I think it’s safe to say that public cloud is not always cheaper.

Security/compliance/data sovereignty – It’s easy to throw up security as a potential way to block a public cloud deployment. There are plenty of organisations running their applications securely in public cloud, so we know it’s possible. Every organisation will need to look at their data and decide whether they are comfortable having it stored in a public cloud.

Data sovereignty will of course form part of this decision, as will compliance. If it’s going to take a 12 month project to work out, if and how, data can be stored in the public cloud, then perhaps it’s just easier to keep it on-premise.

Performance – If you need very high performance, then public cloud may not be the best option. For example; if you need to run bare metal workloads, or require low latency, or require some type of specific hardware.

“What about the application”, I hear you cry. It’s a great point. Are your legacy applications going to run well in a public cloud? Does your application resiliency rely on features such as VMware HA, DRS, or Fault Tolerance?  If it does, and those features aren’t available from your public cloud provider, then what happens to the application when a physical server fails or is taken down for maintenance?

Answer: the application goes down.

These are important considerations you will need to think about when deciding which applications can be run in a public cloud.


If you want the benefits of public cloud but want to do it on-premise, then you need to look at private cloud. To be clear, this is more than just server virtualisation. Private cloud should also provide some level of automation, a self-service portal, and maybe flexible pricing. There are a myriad of options when it comes to private cloud platforms/software.

One option I really like is Cisco UCS Director, or UCSD for short. UCSD is an infrastructure provisioning tool, or in other words, it provides IaaS capabilities. The reason I like it so much is how quickly it provides value. Within just a few hours you can install UCSD and have a self-service portal where users can request virtual machines, which UCSD will deploy automatically. Spend a few more hours and you can add bare-metal servers, storage, network, and security to the list of catalog items available on the portal. Getting to this level of functionality with other private cloud solutions can take weeks or even months.

Everyone’s talking about OpenStack. Customers like the idea of open source software, and vendors are either creating their own OpenStack distribution or making sure their products integrate with it. From speaking to colleagues and to customers, I’ve been told that OpenStack requires a significant amount of resource to get it working and to operate it. That’s why I’m really excited by a recent acquisition Cisco made of a company called Metacloud, which we’ve just rebranded to Cisco OpenStack Private Cloud. This provides an on-premise – meaning behind the customer firewall – private cloud solution based on OpenStack that Cisco engineer, deploy, and remotely operate. This means you get all the benefits of OpenStack without the pain of having to deploy and manage it yourself.


“Buy the base; rent the peak”. That’s a term I’ve heard a few times with regards to hybrid cloud. What it means is that you own enough infrastructure to cover normal demand, and use public cloud at times when you need additional capacity. That’s just one use case for hybrid cloud.

The challenge I see with hybrid cloud is how you manage and secure multiple clouds. Furthermore, how do you connect these clouds together so that you can move workloads between them?

Cisco is working on a solution, called Intercloud Fabric. Intercloud Fabric is software that helps organisations build a hybrid cloud. It provides centralised visibility of both private and public cloud resources, and it allows you to place workloads in either. Crucially, it provides common network and security policies across your private and public cloud environments.


Ultimately I believe organisations will end up with a hybrid cloud deployment. They will use an on-premise private cloud for legacy, core, or sensitive applications. For other applications they will use multiple different public cloud providers. In that type of environment, keeping control of all the different workloads will be the critical challenge. Speak to Cisco to find out how we can solve that for you!

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