Comparing IaaS Providers: Cost, Security, Location

Cloud Computing is one of the hot topics of the moment and everyone has an opinion on it. The term “Cloud” covers a number of deployment scenarios, including PaaS (Platform as a Service), SaaS (Software as a Service) and IaaS (infrastructure as a Service). In this article I’ll discuss the latter, including the use of Cloud Computing to deploy infrastructure and servers and storage from Cloud Service Providers.

The National Institute of Standards and Technology (NIST) defines Cloud Computing as follows:

“Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.”

As we will see, although Cloud Computing should meet the above definition, there are also other requirements that should be considered before selecting a service provider.

Understanding IaaS, Infrastructure as a Service

It is important to understand what is meant by Infrastructure as a Service as we delve into what’s available in the commercial marketplace. IaaS could be described as the foundation or lowest tier in the Cloud Computing stack. In short, it refers to the deployment of traditional infrastructure components such as servers and storage. Today this usually means virtual infrastructure, as the need to have dedicated servers is diminishing rapidly. However, it is not a requirement for Cloud Computing to be deployed with a virtualized environment.

Using Infrastructure as a Service has a number of distinct benefits:

• It enables the customer to understand the provided resources in terms of components they would traditionally deploy in their own data centers. This means existing skill sets around server, database and application administration can all be retained and re-used.

• It provides a degree of portability between service providers and the customer’s own existing infrastructure as deployment takes place on standard platforms such as Windows and Linux.

• There is no requirement to learn new application or programming frameworks as there is with PaaS and SaaS.

• The isolation of resources at the virtual server level means the customer has control over the storage of data, including additional encryption and security measures.

IaaS is therefore a low risk way to evaluate and dip a toe into the Cloud Computing universe. In order to evaluate which provider best suits your requirements, there are a number of considerations to weigh.

IaaS Location

Cloud Computing is provided through the Internet, but at some point there are physical servers, storage and networking equipment deployed in a data center on to which your service will run. Therefore latency can be an issue, depending the application you are deploying.

Most IaaS providers operate from multiple locations. If they don’t then they are probably not worth considering because (as we’ll discuss later), operating out of a single data center presents issues around availability.

As an example, Amazon Web Services (AWS) is available in 5 regions globally; Northern Virginia and Northern California in the USA (known as US East and US West respectively), Ireland in Europe and Singapore and Tokyo in Asia Pacific. This geographic diversity allows applications to be provided globally with minimal latency impact.

Look for service providers that can provide services in your region and the business continuity they provide for those locations.

IaaS Redundancy and Availability

One benefit of providing multiple locations is that of increased availability. The question of course, is how that availability is implemented. AWS, for example, uses availability zones within regions. These are physically separate data centers (possibly in separate locations, but not guaranteed to be so) between which data is replicated.

In the event of a single data center location, it should be possible to restart applications in another part of the availability zone. Unfortunately a recent AWS outage highlighted the fact that the region and availability model was not infallible. Deploying across multiple regions or locations can increase availability.

Infrastructure providers are unlikely to offer services to enable the automated failover and management of applications, therefore it will be incumbent on the customer to look at how geographic resiliency can be implemented.

IaaS Features

As we start to discuss the provision of services, it is a good point to delve deeper into what those services actually are. There are two features that almost all IaaS providers offer and both should be considered essential to offering a cloud-based infrastructure service. They are server/compute and load balancing.