If you’ve read cloud migration case studies and presentations at conferences for new cloud migration tools, it would be easy to believe migrating to the cloud is straight-forward, if that were true then why do a third of them fail?
One of the main reasons is underestimating the scale and complexity of a project to move existing applications and services into the cloud.
Legacy IT estates are a complex web of monolithic applications built on diverse technologies and interconnected by diverse point to point technical and manual integrations.
If service owners are not consulted it can cause major blockers and on-going transformation work needs to be taken into account as well.
Without specialist skills the learning curve for existing in-house resources in designing, securing, testing and deploying services into a cloud environment will be significant.
Cloud vendors provide a rich palette of tools and solutions giving multiple options to solve the same problem. A tool might initially look ideal but present issues further down the project timeline. Ensure architectural best practices are followed to minimise outages and improve the long term quality of the service.
We all know humans suffer from optimism bias and under-estimate complex tasks. To manage expectations it is worth adding a significant buffer to timelines and costs.
Moving to the cloud will cost significantly more if the design is not cost-optimised using the Well-Architected Framework. The framework will be discussed in detail for another article. 
An analogy, Chris Porter, M.D of Digital Transformation at 6point6, says “think of your IT as a Car. Owning a car is cheaper than getting a taxi to work every day in the long term, the CapEx (Car) costs are less than the OpEx (Taxi) costs over several years. Having a reserved Taxi waiting on your driveway with the meter running is going to cost significantly more than ordering a Taxi each time you use it.“
Migrating the data from legacy estate to the cloud is a significant undertaking in its own right. Generally, importing data into cloud platforms is free, data exported can be costly. Consider this before implementing multi-region solutions, and ensure cost-optimised storage services are used to store the data.
The drivers for migrations can vary. Some may require savings in the longer term, others may want agility and the latest SaaS offerings imminently. It all depends on the requirements, time, and budget. A data centre closure could leave a business with no choice but to re-host, in this case a tactical lift and shift (although not ideal) can be the best decision.
If the driver is primarily saving money, then consider re-evaluating. Reducing operating costs is a direct result of improving the architectural design, it is important to consider that the migration itself will have a large upfront cost.
Depending on how far into the future the business is willing to look before realising the value and the return on investment, will determine how successful the migration is. A strategic motivation for long term benefits should be at the core of decisions taken before and during the migration.
The crux of the migration is the approach, of which there are 6 main methods which are commonly referred to as the 6 R’s [ 2 ].
The challenges of migrating legacy applications and infrastructure shouldn’t be under-estimated, provided you have the skills, time and budget a Cloud Migration is a viable and suitable solution to unlock the benefits of the Cloud.