The Doppler Quarterly Summer 2018 - Page 69

A prescriptive planning approach for migration sequencing in your large-scale public cloud migration project. When an enterprise has a large portfolio of applications slated for migration to the public cloud, there is a need to identify the sequencing and scheduling aspects of the migration. In this article, we will describe a real-world planning exercise we undertook, highlighting the various elements essential to any planning and sequencing operation. The following framework was used for migration sequencing: • Develop a rules and scoring system that assigns a score to an application based on preferences, such as less complex applications should migrate first, and dependent groups of applications must be migrated together. • Determine the scale and velocity of the migrations, including how many applications can be migrated in a given time period. • Create a schedule with preferences for what days migration can and cannot be done – such as, no migrations can be performed on holidays. • Create a backlog and iteratively apply any schedule preferences to select applications for migration -- similar to a development project where work from a backlog is added in a sprint for development. Rules and Scores Suppose we have 100 applications to migrate in a given time frame. To objec- tively assess so many applications, we use a set of rules to score various appli- cation components. Each rule has a base score for a specific characteristic of an application component, and then additional points are added to indicate various aspects of the characteristic - risk, complexity, effort, etc. Rules can use weights to influence preferences when base scores are similar. All scores are added up and the final scores indicate the order of migration. The lower the score, the easier the application is to migrate (meaning less complex- ity, less risk and lower effort required), and the earlier it should be placed on the schedule. SUMMER 2018 | THE DOPPLER | 67