Cloud Insight

Cloud is a promise, rain is the fulfillment!

Though, I would like to stay away from primers, I want to explain what my own understanding of some of the terms that I will use regularly on this blog. I will try to write this in as simple non-technical English as I can.

Let’s start with SaaS, Software as a Service. SaaS as the name suggests is a delivery model to provide software as paid service. The software is not installed on your own machines, but the vendor provides the complete package as hosted solution including the infrastructure. The software vendor may in turn rely on hosting providers who manage their server farms, provide disaster recovery, load balancing, mirroring and other infrastructure needs, but the end user does not have to be concerned with this. The end user is mostly interested in functionality, costs per user, uptime, associated SLAs, ability to integrate data with other systems etc. The customer pays for the software on a subscription basis. The poster child for this is Marc Benioff’s salesforce.com.

In general under SaaS, the software delivered is multi-tenant model, as in multiple customers can use it with the clear understanding that one customer will not be able to access another customer’s data. Multi-tenant is not the same as virtualization, a misconception spread by even the gurus in this world. Virtualization is the ability to slice hardware to represent multiple virtual machines (VM). So for example, a high end Sun server can be sliced into 10 different virtual servers. Each VM then represents a server. One VM may host the SQL database on one virtual machine and a web server on another etc.

Providing computing resources including software, storage or hardware as subscription based service is utility computing. The key difference here is utility computing is not limited to software. It could be any form of computing resources. The mainframes providing time-sharing was earliest form of utility computing. Any ISP renting disk space to store backups is another simplest example.

On-demand software is synonymous with SaaS and On-demand computing is synonymous with utility computing. It is opposite to on-premise where you purchase the software/hardware and deploy it on your own servers/networks.

Now coming to cloud computing. There has long been the dissociation of physical infrastructure and software application design. Cloud computing takes this a few steps further where designers and users need not be concerned with how the different computing resources and services that are combined in an application or service are coming from. For example, Amazon S3 is providing storage space to many applications including Basecamp.

Even though we generally talk of external services such as Amazon, clouds could also be internal. Many IT departments have been functioning in this way for a long time. A simple example is having a centralized group to manage all SQL DB resources. The DB group within IT provides an SLA based service to all other groups where developers from can request DB resources for development, testing, staging and production environments. They work with the DB group getting sizing information based on their logical models, number of users and growth expectations.

There are a number of other concepts that come into picture with cloud computing including business services management [BSM] where your business and IT services may reside in or outside of your enterprise boundaries, business process management [BPM] where the services orchestrated may be provided by multiple vendors or internal resources. Enterprise IT architecture will now need to go way beyond the enterprise.

Does this give a sense of impact of cloud computing? The promises are many but fulfillment of this on the way. Reminds me of an old Arabic saying, cloud is a promise, rain is the fulfillment.