ADR 018: Database Patterns

Status: Proposed | Date: 2025-07-28

Context

Applications need managed databases with automatic scaling and jurisdiction-compliant backup strategies.

• AWS Aurora Serverless v2 Documentation
• Percona Everest Documentation and Pigsty Documentation for development/non-AWS environments

Decision

Use Aurora Serverless v2 outside EKS clusters with automated scaling, multi-AZ deployment, and dual backup strategy.

Implementation

• Database: Aurora Serverless v2 (PostgreSQL/MySQL) with built-in connection pooling and automatic scaling
• Deployment: Outside EKS cluster (handles complexity automatically)
• Credentials: Follow ADR 005: Secrets Management for endpoint and credential management
• Backup: Follow ADR 014: Object Storage Backups plus AWS automated snapshots
• Security: Follow ADR 007: Centralized Security Logging and ADR 012: Privileged Remote Access

Consequences

Benefits

• Cost Efficiency: Serverless scaling reduces costs during low usage
• Low Maintenance: Managed service with automatic scaling and high availability
• Compliance: Dual backup strategy meets jurisdiction requirements

Trade-offs

• Vendor Lock-in: AWS-specific (consider Percona Everest or Pigsty for development/non-AWS)
• Cold Start: Brief delays when scaling from zero