Is Your Cloud Opaque or Transparent?
Cloud computing promises customers the ability to deliver scalable applications on-demand without the overhead of a massive data center. The visibility - and flexibility as well as control - you have into and over the cloud computing environment depends on whether the provider you select offers an opaque or a transparent cloud computing environment.
OPAQUE CLOUD COMPUTING MODEL
In an opaque cloud computing model all details are hidden from the organization. The hardware and software infrastructure details are not necessarily known or controlled by the organization but are completely managed by the cloud computing provider. This allows for a completely on-demand environment in which all resources necessary to deliver applications according to service level agreements are automatically provisioned, de-provisioned, and managed by the cloud computing provider.
The organization need only develop and deploy the application to the cloud, the rest of the details are opaque and handled for the organization by the cloud computing provider. Most opaque cloud computing providers currently allow the organization to determine how many "instances" of their application is running at any given time, with the details of provisioning the appropriate resources to support those instances hidden from the customer view.
In many ways, SaaS (Software as a Service) providers such as Salesforce.com have been using an opaque cloud computing model for many years, as the implementation details in terms of hardware and software infrastructure are completely hidden from and unavailable to the customer (the organization). The difference between a SaaS offering and an opaque cloud computing model is in the application development and deployment processes. A SaaS offering such as Salesforce.com or Google Apps requires development of applications on a specific platform, almost always proprietary to the SaaS provider and non-negotiable.
An opaque cloud computing provider allows the organization to determine the platform upon which applications will be deployed, more akin to some of Amazon's cloud offerings, such as EC2, though the underlying operating system and hardware may not be known due to the extensive use of operating system virtualization by the cloud computing provider. This is why virtualization is inexorably tied to cloud computing - it is the most efficient way to deploy an application to a remote, virtual data center without the overhead of configuration and management of the incredibly high number of combinations possible for application platforms. Opaque cloud computing providers like Joyent have an infrastructure already constructed to scale. Customers may be aware of what that infrastructure comprises, but cannot necessarily specify the choice of switches, routers, or application delivery infrastructure.
TRANSPARENT CLOUD COMPUTING MODEL
In a transparent cloud computing model the organization is left with determining its specific needs. The organization decides how much computing power it requires, what hardware and software solutions it will require, and it manages its provisioned resources in the cloud.
The transparent cloud computing model is more akin to an outsourced data-center, a virtual data center if you will, than it is to an on-demand opaque cloud computing model. The acquisition and provisioning of resources becomes much difficult in a transparent cloud computing model.
The prospect of automated on-demand computing in a transparent cloud computing model is good and in some cases already available for some functions. The same mechanisms used to manage the opaque cloud computing environment could become customer-facing ones. Some management and configuration of cloud computing resources are currently being offered to customers by providers like RightScale, though what infrastructure functions can be delegated to the organization vary greatly from provider to provider.
Rackspace is a good example of a transparent cloud computing model, as are many of the traditional hosting providers. The transparent cloud computing environment is still evolving, currently comprising several different models for architecting your infrastructure. Some, like Areti, offer flexibility in infrastructure choices by taking advantage of virtual appliances. This allows the customer to choose from a number of application and network infrastructure solutions while keeping the cost of acquisition and management down for both the provider and the customer. Other providers continue to focus on physical infrastructure deployment in a fully or collaboratively managed environment, understanding that some organizations will require dedicated, proven solutions if they move into the cloud.
THE HYBRID MODEL
CIO.com recently offered a list of 11 cloud computing vendors to watch, culled from a Forrester Research report. The list comprises a mix of opaque and transparent providers, with a tendency to lean toward the opaque. A few of the providers on the list are leaning toward a hybrid cloud computing model, with the ability to specify a choice of infrastructure devices from those supported by the provider while providing fully managed services.
A hybrid model is likely where providers will eventually converge, as it promises to provide the greatest flexibility for customers without sacrificing some of the control necessary on the part of the provider. After all, while allowing customers to manage and configure some components of the application delivery network, others (routers, switches) are likely to not require such hands-on management by customers. In fact, such mucking around at layer 2 and 3 could very well do more harm than good, as most value added features and functionality for application delivery comes at layer 4 and above and is best handled by a solution separate from core network infrastructure. And while many customers will be comfortable testing the waters with virtual appliances or open-source solutions for application delivery infrastructure, eventually more proven solutions will be required as customers begin to demand more flexibility and functionality in the cloud. Cloud computing providers who evolve quickly and take advantage of componentized application delivery infrastructure will be able to better differentiate their offerings by offering additional features such as acceleration, security, rate shaping, and advanced authentication.
These advanced features are one of the primary reasons that "Option #3" will be increasingly important for application delivery and networking infrastructure providers. Cloud computing providers appear willing to support such features, but require that the solutions be able to be integrated and remotely managed, on-demand, before they will do so.
