Design Decision Record (DDR) Example

1. Overview

• Title: Adoption of Microservices Architecture for E-Commerce Platform
• Date: November 10, 2024
• Status: Accepted

2. Context

• Background: The current monolithic architecture of the e-commerce platform has led to scalability and maintenance issues. As the user base grows, it is becoming increasingly difficult to manage deployments, and the development cycle is slowed due to tight coupling between services.
• Goals and Objectives: The goal is to enhance scalability, improve the maintainability of the platform, and accelerate the development cycle by decoupling services.

3. Decision

• Decision Statement: Move from a monolithic architecture to a microservices architecture for the e-commerce platform.
• Alternatives Considered:
• Alternative A: Maintain Monolithic Architecture
  • Pros: No significant upfront cost, retains the current working system without disruption.
  • Cons: Limited scalability, complex deployments, and slow development cycle.
• Alternative B: Modular Monolith
  • Pros: Easier migration path, some level of decoupling while maintaining a single deployment unit.
  • Cons: Scalability still limited compared to microservices, not a complete solution for the challenges faced.
• Alternative C: Microservices Architecture (Chosen Option)
  • Pros: Enhanced scalability, independent deployment of services, and faster development.
  • Cons: Increased complexity in managing distributed systems, higher initial costs, and learning curve for the team.

4. Reasoning

• Rationale: Microservices architecture was chosen because it best meets the scalability and maintainability needs of the platform. While there are higher initial costs and complexity, the long-term benefits of improved agility, scalability, and resilience outweigh these drawbacks.
• Criteria for Evaluation: Scalability, maintainability, team capability, cost, and development speed.

5. Implications

• Consequences:
• Positive: Improved scalability and resilience, faster development and deployment of individual features, enhanced fault isolation.
• Negative: Increased complexity in service orchestration and monitoring, need for more robust DevOps practices.
• Technical Debt: Initial adoption of microservices may introduce technical debt in the form of legacy services that need to be broken down gradually. Proper documentation and phased migration are required to manage this debt.

6. Mitigation and Follow-Up Actions

• Mitigation Measures: Implement comprehensive DevOps tools and practices to manage microservices complexity, such as container orchestration (Kubernetes) and distributed tracing.
• Follow-Up Tasks:
• Set up a cross-functional team for microservices migration.
• Train development teams on microservices best practices.
• Establish monitoring and alerting for service health.

7. Stakeholder Input

• Stakeholders Involved:
• Product Owners: Emphasized the need for faster feature releases.
• Developers: Highlighted concerns about the learning curve and increased complexity.
• Operations Team: Raised concerns about monitoring and maintaining distributed systems.
• Stakeholder Concerns: Addressed by planning training sessions and involving operations early in designing the monitoring solution.

8. Status and Review

• Status Updates: The decision has been accepted, and the project is in the planning phase for migration. Status will be updated as milestones are completed.
• Review Timeline: The decision will be reviewed in 6 months to assess progress and adapt the approach if necessary.

9. Documentation and Storage

• Location: Stored in the project Confluence under “Architecture Decisions”.
• Related Documents: Links to the migration plan, system architecture diagrams, and DevOps tool implementation guides.

Supporting Questions

• What alternatives were considered, and why were they rejected?
• Alternatives included maintaining the monolithic architecture and transitioning to a modular monolith. They were rejected due to scalability limitations.
• How does this decision align with the overall project goals?
• Aligns with goals of improved scalability, maintainability, and faster feature development.
• What are the short-term and long-term implications of this decision?
• Short-term complexity and cost increase, long-term benefits in agility and scalability.
• Are there any potential risks or areas of uncertainty that need monitoring?
• Risks include increased complexity, distributed system management, and potential service failures. Monitoring will be implemented to mitigate these risks.

Roles and Responsibilities

• Decision Maker: Sarah Lewis, Chief Architect
• Stakeholders: John Doe (Product Owner), Maria Smith (DevOps Lead), Alex Brown (Developer Lead)
• Document Owner: Emily Carter, Senior Developer

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This DDR example illustrates a well-documented design decision for adopting a microservices architecture. It includes the context, reasoning, and implications to ensure transparency and alignment with project goals.