Playing with the building blocks of the cloud: Getting IaaS right

Summary:Infrastructure as a Service is the fundamental basis of all cloud services. Here we look at how to get started with IaaS, what skills you'll need in-house and which applications will (and won't) thrive in the cloud.


...they are moving to the cloud is simulations or high-performance computing — enormous batch jobs where organisations need to do smart analysis on giant datasets.

"Those are typically jobs where you might need 10,000 processsors, but you only need them for half a day or a couple of hours. With cloud you only pay for the time you need them — you don't have to invest in hardware that you would only use a couple of days a month, so that's the ideal scenario", Petri said.

What can't be moved to the cloud?

Organisations are also looking at taking their in-house applications and moving them to the cloud, but here some additional complexities creep in. Most cloud computing providers only offer x86 servers, so if you have Unix or AS400 there are only very few providers that have something that looks like the cloud for those applications. And the organisations need to be sure that they are moving an application that can utilise the benefits (fast provisioning, flexibility and scalability) that are the main selling points of the cloud.

"The cloud is not a default option: you have to look at what makes sense. Flexibilty, agility and elasticity — those are more reasons to move to the cloud than necessarily cost. If I want to run a workload on 10,000 processors for an hour then it's a lot more cost effective to just pay for that hour rather than buying a machine and running it in-house, so you can say its cheaper although that's a very special scenario. But if I need a machine for the next 36 months and it will be used 24 hours a day, you really have to look at the cost and in-house might be cheaper — but how many systems do we have today where you can predict usage that clearly?" Petri said.

One of the most important things to do when considering the use of IaaS is to get your hands dirty. Start with a small, non-essential system or a new project, and try out some cloud providers, analysts suggest.

Companies also need to consider their existing infrastructure: one option is to keep core workloads in the corporate data centre and place 'bursty', variable workloads in the cloud. In contrast, for a startup, without capital and without its own data centre, cloud might make sense as using cloud services will shift spending from capex to opex.

Will every application move to the cloud eventually?

Certain systems — the ERP systems that are the nervous systems of large organisations, for example, might at first glance seem impossible to move onto the cloud. But even here there is potential to rethink the existing infrastructure. For example, these apparently monolithic applications tend to have a variety of secondary systems — a test system, an acceptance system, a fallback system and a disaster recovery system, for example — that aren't all used at the same time. There's an opportunity in moving some these to the cloud.

Also, from the service provider viewpoint these are complex configurations, and so providing a offering here could deliver a good margin (especially if they can offer the same service to a number of customers). The workloads that may well be left in the corporate data centre could be those niche applications that no vendor particularly wants to support in the cloud, or ones that do not benefit from the flexibility or scalabilty inherent in IaaS.

Getting started with IaaS

One of the most important things to do when considering the use of IaaS is to get your hands dirty. Start with a small, non-essential system or a new project, and try out some cloud providers, analysts suggest.

"What you don't want to do is a large evaluation of many, many cloud providers and then try to find the ideal one without ever having used the cloud. That's what you would have done in the past with ERP systems: those were very complex and hard to comprehend, so you did a paper evaluation using criteria," Petri said.

Test each of the main cloud providers — Amazon Web Services , Microsoft's Azure and perhaps a local provider, and see which option fits best. Because of the pay-as-you-go nature of IaaS it's easy to test out a few options by spending just a few pounds or dollars.

Once your developers have some hands-on experience, you can start the deeper due diligence around certification, the additional services needed, details of service level agreements or the average length of the provider's customer relationships.

"That's what we sometimes see missing with customers: they start a very theoretical evaluation, but hardly have any hands-on experience, and that makes it very hard to make a good decision," Petri said.

Topics: Cloud


Steve Ranger is the UK editor-in-chief of ZDNet and TechRepublic, and has been writing about technology, business and culture for more than a decade. Previously he was the editor of

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