The dividing lines between Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS) are blurring. But according to Phil Brindley, CTO, The Bunker, the dominance of the latter belies the importance of the former in the Cloud Computing arena and there are several reasons why both will remain as distinct layers and product sets.
Phil Bindley commented: "PaaS has rapidly become a darling thanks to the rocketing demand for applications and the need to find faster, more cost-effective models for their development and delivery. The latter has always been a convoluted process that's costly in terms of time and resources, while more complex applications require sophisticated infrastructure and can prove difficult to scale or update. There's also the scenario where a new business requirement calls for a change in the application and results in a lengthy development, test and redeployment cycle."
PaaS was conceived to remove all of these headaches by enabling consumers to access custom applications built in the Cloud in the same way they do with those delivered under Software as a Service (SaaS).
By enabling consumers to spin-up dedicated environments optimised for their applications in an instant, PaaS makes it possible to write entire platforms in Open Source, release small work packages regularly, and switch seamlessly between test and development and production.
"Yet PaaS remains at an early stage of adoption. Although independent software developers (ISVs), IT organisations and e-commerce providers have long recognised the benefits of PaaS, the evolution of Infrastructure as a Service (IaaS) has made the market considerably more confusing for enterprise consumers when it comes to distinguishing between the two," continued Phil.
In its purest form, IaaS would consist only of compute, storage, network, leaving the consumer to deploy, manage and maintain the OS. Since there are few scenarios in which a consumer would want to acquire IaaS without the OS necessary to run that infrastructure, the majority of Cloud Service Providers (CSPs) deliver IaaS together with an OS as standard.
"CSPs have muddied the waters by evolving their IaaS offerings further. They've added management and security components around the OS, as well as features such as automated virtual machine deployment, and badged these services as 'PaaS'. Although buying a service in this way enables consumers to benefit from the flexibility, scalability and utility consumption model that Public Cloud brings, they don't receive any form of management or monitoring of that infrastructure and associated data centres from the CSP," added Phil.
Because Public IaaS/PaaS is based on shared resources (multi-tenanted), often across multiple sites and multiple countries, it represents additional risk for enterprise consumers if they're looking to migrate business-critical applications or sensitive data.
Conversely, when PaaS is sourced from a Managed Service Provider (MSP), it is delivered on Dedicated or Private Cloud Infrastructure. With the infrastructure managed and operated solely for the consumer (i.e. it is provisioned on dedicated physical systems), the 'Private PaaS' model is preferred by security conscious outsourcers, since the MSP can provide access controls, encryption and segregation to ensure the confidentiality, integrity and availability of their applications and data.
"A further key difference between Public IaaS/PaaS and Private PaaS lies in the resources that fall within the customer-managed stack. Under Public IaaS/PaaS, the consumer remains responsible for the middleware that sits between the application / web layer and the database, such as Microsoft Exchange, SQL, or the database application server or web server," added Phil.
With Private PaaS, the MSP is responsible for managing both the underlying cloud infrastructure and an agreed set of applications including the middleware. The consumer retains control over the deployed applications and, potentially, the configuration settings for the application-hosting environment.
As such, Private PaaS allows consumers to develop, run and manage applications without the associated complexities of maintaining the underlying infrastructure. Instead, they can focus on their core business, whether it's delivering SaaS to internal or external customers, enhancing their storefronts, or adding value to other areas of their organisation.
"IaaS may still be the fastest growing segment of Cloud computing, but it's PaaS that will allow developers to create new 'cloud-aware' applications with the potential to transform both their own business and those of their customers and their customers' end users too," concluded Phil.