For years now those of us who talk Cloud on a daily basis have used variations on a triangle shape as a way to articulate what Cloud actually is and how the various services that make up Cloud can be differentiated.
Traditional thinking (if one can have traditional thinking in a space as young as Cloud) is that Cloud is made up of three distinct parts. At the bottom of the triangle you have Infrastructure as a Service (IaaS) essentially the move from physical hardware to virtualized hardware (let’s not argue the definition at this point). Next up in the middle layer of the triangle is Platform as a Service (PaaS) – an even more confusing acronym that is generally accepted to mean some kind of scalable and automated development environment.
At the top of the triangle we have what is probably the most easily understood part of Cloud, perhaps because of the work that early vendors like salesforce and NetSuite did. Software as a Service (SaaS) is the delivery of software built for the web – scalable, browser based, pay per use or variations on those themes.
We even have our own version of the triangle – in our case we developed this one for our Cloud Stack report for CloudU (see below);
This way of describing the Cloud has been a useful tool – it’s simple, is reasonably understood and compartmentalizes things nicely for a non technical audience. Recently however this triangle metaphor has been questioned a little. A number of innovations have made a simple three level stack a little too simple;
– IaaS vendors have started adding more automated and “platform-like” services into what they do
– PaaS has become a little fragmented from automated application deployment options at one end, to high level declarative environments for creating business applications on the other
– Even SaaS, arguably the simplest of the three to understand, has been extended with extremely rich customization options that see it nudge downwards into PaaS’ space
At the recent Structure conference in San Francisco, Werner Vogels of Amazon Web Services suggested in his ”State of the Cloud” address that the stack model is now outdated and should be left behind. Rather there is a notion of a service-based architecture with containerized services and applications that are interconnected.
It’s an interesting notion – the difficulty I have with it however is that no matter how ragged the triangle metaphor becomes, it is still a highly effective tool for communicating to non-technical audiences the different aspects of Cloud. For this reason, I’ll be continuing to talk about triangles – in all their imperfect glory. Read more about what Cloud can offer small and medium businesses at CloudU.
(Cross-posted @ The Diversity Blog – SaaS, Cloud & Business Strategy)
So, this is a useful meme to push out into the public discussion.
I’m inclined to agree with you, Ben. Stack layers are not only helpful from an explanatory standpoint, but they’re useful in understanding where the highly abstracted layers of a cloud architecture separate themselves from each other.
I say we keep it.
Rock on, my friend.
Thanks RC – keep up the feedback!
Hi Ben – we are a social business platform based in Europe and have been, I believe, fairly well ahead of the curve in SaaS and PaaS solutions for business.
Our triangle diagram also helps with client explanations and is here :
http://www.siteforum.com/architecture
Our 3 layers our Applications, then the development environment and other tools for extensions and integration, finally the cloud-based platform itself.
Thanks David, good diagram!