A recent study  has clearly established that application development is moving fully into the cloud,* and the days of the traditional, monolithic architecture are clearly numbered. Whilst this is clear for so called “cloud native,” so applications born in the cloud, there is still a question of what do to with the old(er) applications?
For many organizations the question of what do to with the traditional (or sometimes also referred to as legacy) is a key one. Moving to the cloud will have affect the application and its underlying infrastructure in one way or the other and failing to consider all implications can cost dearly—both commercially and/or from a data security perspective. To prevent unwanted surprises a detailed assessment is needed to understand the various different options.
Typically a cloud assessment for existing application will consider various different aspects covering application, infrastructure as well as security, data and commercial considerations. The objective is to establish the impact and therefore the options for transforming an existing application to the cloud:
1. Technically supported
- Will the technology that the Application is based on, run on the target cloud platform? If no, is there an alternative available to “cloud-enable” the application?
- Does the application require any hardware near devices like dongles?
2. Data access/interfaces
- Does the application require constant and heavy data interfaces to a number of application not hosted on the cloud?
- Is there a need to exchange large amount of data from local to cloud and back?
3. Network impact
- Will the move from a local application server to a central cloud platform impact the WAN?
- Bandwidth: is there enough bandwidth available to support the increase?
- Latency: does the application require low/very low latency?
4. Business criticality
- If the WAN goes down can the end user live without the application for a period of time?
- Does the application support a service-oriented/modular approach?
5. Service levels
- Does the cloud provider (whether local/private/hybrid-to-public) deliver the same or better SLAs (Service Level Agreements) and KPIs (Key Performance Indicators)?
6. Data security
- Is the/are the data retained restricted and/or critical to the business?
- If so are there any limitations for retaining this data at a different location?
- Is there a large/very large backup/restore/archiving requirement?
8. Business case
- Value For Money: What is the value of moving this application to the cloud?
- TCO: Will it drive overall cost reduction (comparing Capex + end-to-end Opex spend)
Each option will come with its own business case to allow an informed decision regarding the future of the application—should we keep it where it is; improve a bit or would it be better to move it to a public cloud platform, or is hybrid a better option?
As with many aspects in technology multiple path are available and as per  it is the job of the cloud architect to facilitate the decision making process, ensuring that the right outcomes are being achieved. Once all considerations have been drawn up the choice is yours; we call this Cloud Choice .
Thanks for Reading.
About the Author: Gunnar Menzel has been an IT professional for over 29 years and is VP and Chief Architect Officer for Capgemini’s Cloud Infrastructure Business. His main focus is business-enabling technology transformation and innovation.
“*” by cloud I refer to a public, private and or hybrid cloud platform.
 Capgemini May 2017, https://www.capgemini.com/cloudnative#mainreport  Capgemini May 2016, https://www.capgemini.com/resources/the-new-role-of-the-architect-central-to-growing-your-business-in-todays-digital-world  https://www.capgemini.com/cloud-choice