Cloud primer

Existing model

When an organisation runs application and infrastructure services on-premises, the internal teams are responsible for procuring, configuring and maintaining the entire technology stack.

All infrastructure, networks, storage and data are hosted in an environment owned and operated by your organisation, or by a delivery partner that you contract with.

You (or your delivery partner) have full responsibility for operating and managing the entire technology stack. This means you must:

• maintain datacentres: purchase and maintain power, cooling, fire suppression
• procure hardware: purchase, maintain and support the underlying datacentre technologies, such as: network devices, storage devices, servers and virtualisation platforms
• security: secure, manage and monitor the physical and logical security of your datacentre
• uptime: meet your uptime agreements (SLAs) with your internal customers, by building in enough resilience and redundancy, and continuously monitoring service stability

Cloud service model

Under the cloud services model, your responsibilities vary depending on the services you selected. However, in all cases, your responsibility for maintaining your service - and the associated operational overheads - is reduced significantly.

The illustration below shows your responsibilities when operating under the different cloud service models.

At one end of the spectrum, there is the traditional on-premises service model, where you are responsible for every aspect of the technology stack. This gives you the greatest level of control, but also has the greatest number of drawbacks and the highest operational overheads.

At the other end of the spectrum, the Software-as-a-Service (SaaS) model removes most of the complexity and effort of operating the service. SaaS solutions are standardised, which results in less flexibility and fewer opportunities for service customisation. This can present its own challenges, but in the long-term, creates better business processes, and avoids the type of practices that have resulted in the legacy systems we have today resulting from insufficient IT estate maintenance.