Enterprises are quickly transitioning their cloud infrastructure from simple storage and backup to a functioning application development and delivery platform. But one of the thornier issues in this process is deciding on the correct architecture to support operational goals.
The three leading choices so far are software as a service (SaaS), platform as a service (PaaS) and infrastructure as a service (IaaS), which can almost be viewed as the small, medium and large of cloud functionality. The choice depends largely on your comfort level in outsourcing the various elements of IT, ranging from just the applications (SaaS) or the entire environment (IaaS).
While backup and other applications are suited to the IaaS model, PaaS is emerging as the go-to platform for application delivery, primarily because enterprises can enjoy all the benefits of application-layer development, testing and deployment without completely surrendering the data center to third-party providers.
Even those providers are starting to prefer PaaS to IaaS, according to TechTarget's Gina Narcisi. For one thing, it allows them to cater to a more diverse clientele by delivering services as simple APIs within the leading virtual operating systems. In this way, the provider has a link to VMware, Hyper-V, Citrix or Linux users, whereas with IaaS, both the provider and consumer need to support largely the same infrastructure. This is crucial for providers like GoDaddy.com, which recently suspended its IaaS service because it didn't mesh well with its client base of mostly smaller enterprises.
Even private clouds are increasingly turning to the PaaS model, says Apprenda CEO Sinclair Schuller. Public services often run into regulatory and security problems and have difficulty tapping the usually large data sets that in-house development requires. PaaS on private infrastructure avoids these issues and can easily be converted to a hybrid model when projects need to be shared across multiple locations. PaaS platforms are also taking the lead in enabling cloud-ready architectures by employing advanced Web-based and SOA techniques to build multi-tenancy and other features into applications. In short, PaaS is leading the way in developing apps for the cloud, not just the data center.
Nevertheless, top data center platform providers seem to be getting on board with PaaS as well. Oracle recently acquired a minority interest in Engine Yard, a San Francisco-based PaaS provider that runs on the EC2 cloud. Although plans have not been disclosed, it seems likely that Oracle will use Engine Yard as the cloud component of its Exadata and ExaLogic systems. Along with the WebLogic application server and GlassFish Java server, this should help Oracle's fortunes as a service provider going up against Salesforce and other established firms.
But while PaaS may be more flexible than IaaS, the fact remains that most PaaS offerings are still proprietary. VMware and the Cloud Foundry Communication are hoping to change that through the Cloud Foundry Core program, a set of common baseline formats and mechanisms designed to improve application portability across clouds. The format has already drawn support from AppFog, Tier 3, Uhuru Software and others, offering enterprises the opportunity to shift projects between PaaS providers just in case costs, user needs and other requirements change. VMware has been pushing for openness in multiple area of the data environment through the OpenFlow network protocol and other means, with the ostensible purpose of helping enterprises build dynamic infrastructures that limit dependency on a single provider — that is, of course, as long as it's on a VMware virtual layer.
PaaS has long suffered from middle-child syndrome throughout much of the cloud era − not as immersive as full IaaS, but more complex than SaaS. In the meantime, a plethora of other service models has arisen to meet all sorts of specific needs, from disaster recovery (DRaaS) to networking (NaaS).
But it just may be that a middle-of-the-road application development model is just what the enterprise ordered. As a commitment, PaaS is neither too big nor too small, but, for many, just the right level of cloud to put new applications into service.