{"id":4528,"date":"2012-11-06T12:00:13","date_gmt":"2012-11-06T12:00:13","guid":{"rendered":"http:\/\/www.markwilson.co.uk\/blog\/?p=4528"},"modified":"2012-11-05T22:16:03","modified_gmt":"2012-11-05T22:16:03","slug":"what-as-a-service","status":"publish","type":"post","link":"https:\/\/www.markwilson.co.uk\/blog\/2012\/11\/what-as-a-service.htm","title":{"rendered":"What-as-a-service?"},"content":{"rendered":"

I’ve written previously about the “cloud stack” of -as-a-service models but\u00a0I recently saw Microsoft’s Steve Plank<\/a>\u00a0(@plankytronixx<\/a>) give a great description of the differences between on-premise, \u00a0infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS).<\/p>\n

Of course, this is a Microsoft view of the cloud computing landscape and I’ve had other discussions recently where people have argued the boundaries for IaaS or PaaS and confused things further by adding traditional web hosting services into the mix*. \u00a0Even so, I think the\u00a0Microsoft\u00a0description\u00a0is a good starting point and it lines up well with the major cloud services offerings from competitors like Amazon and Google.<\/p>\n

Not everyone will be\u00a0familiar\u00a0with this so I thought it was worth repeating Steve’s description here:<\/p>\n

\"\"<\/p>\n

In an on-premise deployment, the owning organisation is responsible for (and has control over) the entire technology stack.<\/p>\n

With infrastructure as a service, the cloud service provider manages the infrastructure elements: network, storage, servers and virtualisation. The consumer of the IaaS service will typically have some control over the configuration (e.g. creation of virtual networks, creating virtual machines and storage) but they are all managed by the cloud service provider. \u00a0The consumer does, however, still need to manage everything from the operating system upwards, including applying patches and other software updates.<\/p>\n

Platform as a service includes the infrastructure elements, plus operating system, middleware and runtime elements. Consumers provide an application, configuration and data and the cloud service provider will run it, managing all of the IT operations including the creation and removal of resources. The consumer can determine when to scale the application up or out but is not concerned with how those instances are operated.<\/p>\n

Software as a service provides a “full-stack” service, delivering application capabilities to the consumer, who only has to be concerned about their data.<\/p>\n

Of course, each approach has its advantages and disadvantages:<\/p>\n