Choose the right cloud migration path
After choosing the cloud deployment model that fits your application your next step is to pick the cloud migration path.
According to Gartner, there are five key cloud migration paths:
- Re-host on IaaS
- Re-factor for PaaS
- Revise for IaaS or PaaS
- Rebuild on PaaS
- Replace with SaaS.
Each of these has their pros and cons and offers opportunity for the systems integrator to add value.
Re-host on IaaS
Applications are migrated into virtual machines and then deployed on IaaS. A quick win for IT with immediate cost savings and access to additional resources. There are times when data may be a problem here. Regulatory requirements may demand data is held within a geographical area for security. Application access to data that is kept locally and not uploaded into the cloud could well pose a challenge in terms of available bandwidth.
Re-factor for PaaS
Applications run natively on the PaaS rather than being installed in customer VMs. This leads to a better level of integration between the applications inside the PaaS and allows the customer to focus on applications rather than the platform. One challenge that must be overcome is the integration of applications on PaaS and those kept on-premise by the customer. Issues over data security and bandwidth are the same as for IaaS.
Revise for IaaS or PaaS
Revising for IaaS and PaaS is ideal for customers who want to extend existing applications to the cloud as part of a distributed application landscape. Developers take advantage of the applications delivered in the PaaS and extend on-premise applications to take advantage of new features. The major challenge is for the developers to understand the issues involved in writing distributed applications.
Rebuild on PaaS
As cloud matures, developers will begin to treat it as a first-class deployment platform. Applications are architected to take advantage of cloud services and interoperate with core systems. This is a complex integration challenge that builds on the integration lessons from “Revising for PaaS”.
In addition to the revise path, the customer can make significant savings from no longer supporting large scale legacy applications. Getting the service levels and disaster recovery processes right is essential.
Replace with SaaS
SaaS offers major savings by lowering the cost of using applications. Users rent rather than buy application licenses. When the application is no longer needed, the license is handed back. For flexible workforces or where contractors are used, the savings are at their highest.
There are challenges with SaaS. The first challenge is that the applications need to be designed for cloud delivery. The second is whether the data should reside locally or in the cloud. This third is ensuring that the software manufacture is willing to license their software for delivery through SaaS. There are already examples of SaaS-ready applications in the area of office productivity, CRM, databases and data analysis tools.
For some mid-sized organizations SaaS offers an exciting opportunity by providing access to applications that were too expensive to be justified previously.
My paper ‘How to move to the cloud’ is a useful guide to a successful migration to the cloud. It’s available to download here!