A company is migrating an application to the cloud for modernization. The engineer needs to provide dependencies between application and database tiers in the environment. Which of the following should the engineer reference in order to best meet this requirement?

A Configuration Management Database (CMDB) is a centralized repository that stores information about an organization's IT environment, including hardware, software, and the relationships between them. These components are known as Configuration Items (CIs). For a cloud migration, the CMDB is the authoritative source for identifying and understanding the dependencies between CIs, such as the specific database instances an application tier relies on. Referencing the CMDB allows the engineer to accurately map these critical relationships, which is essential for planning the migration strategy, ensuring service continuity, and avoiding post-migration failures.

A. Internal knowledge base article: This may contain anecdotal or outdated information and is not the structured, authoritative system of record for configuration dependencies.
C. WBS: A Work Breakdown Structure is a project management tool that deconstructs project deliverables into tasks; it does not document technical infrastructure relationships.
D. Diagram of physical server locations: This illustrates the physical layout of hardware in a data center, not the logical service dependencies between application and database tiers.
E. SOW: A Statement of Work is a contractual document defining project scope, timelines, and deliverables, lacking the granular technical details of IT component dependencies.

1. Keller, W. (2015). IT Service Management and ITIL. Lecture Notes, Institute for Strategy and Business Economics, University of Zurich. Section 4.3.2, "Configuration Management Database (CMDB)," describes the CMDB as the central database for storing CIs and their relationships, forming a logical model of the IT infrastructure.

2. Al-Masri, E. (2018). Migrating IT Services to the Cloud: A Practical Guide. IEEE Cloud Computing, 5(2), 54-63. In the "Discovery and Analysis Phase" section (p. 57), the paper emphasizes that identifying service dependencies is a critical prerequisite for migration and notes that tools like a CMDB are used to discover and map these relationships. https://doi.org/10.1109/MCC.2018.022171661

3. Stanford University (2023). ITSM Program: Configuration Management. University IT Documentation. This resource defines the CMDB as the "single source of truth for IT infrastructure, applications, and business services and the relationships between them," which is precisely the information the engineer requires.