Open Policy Agent

Open Policy Agent (OPA) is an open-source, general-purpose policy engine that unifies policy enforcement across the cloud-native stack, enabling the practice of "policy-as-code." It decouples policy decision-making from application logic by providing a central service that other systems—such as microservices, Kubernetes, or CI/CD pipelines—can query to offload complex authorization decisions. Using its declarative language, Rego, developers and operators can write fine-grained, context-aware policies to enforce security, compliance, and operational guardrails consistently throughout their entire technology landscape.

1. Introduction to Open Policy Agent
   1. What is Open Policy Agent
      1. Definition and Core Purpose
      2. General-Purpose Policy Engine Concept
      3. Decoupling Policy from Application Logic
      4. Policy Evaluation Architecture
   2. History and Evolution of OPA
      1. Origins and Development Timeline
      2. Key Milestones and Releases
      3. Community Growth and Adoption
   3. OPA in the Cloud Native Ecosystem
      1. CNCF Graduation Status
      2. Integration with Cloud Native Technologies
      3. Role in Modern Infrastructure
   4. Policy-as-Code Paradigm
      1. Traditional Policy Management Limitations
      2. Policy-as-Code Definition and Principles
      3. Version Control for Policies
      4. Automation and Continuous Integration
      5. Collaboration and Team Workflows
      6. Testing and Validation Capabilities
      7. Modularity and Reusability Benefits
   5. Core OPA Architecture
      1. Policy Engine Components
      2. Data Flow Architecture
      3. Decision Making Process
      4. Input Processing
      5. Policy Evaluation Lifecycle
   6. Fundamental OPA Concepts
      1. Policy Documents
      2. Data Documents
      3. Input Documents
      4. Query Mechanism
      5. Decision Output Format
      6. Decision Logging
   7. Primary Use Cases
      1. Kubernetes Admission Control
      2. Microservice Authorization
      3. API Gateway Policy Enforcement
      4. CI/CD Pipeline Guardrails
      5. Infrastructure as Code Validation
      6. Data Access Control
      7. Application-Level Authorization
      8. Cloud Resource Governance
      9. Compliance and Regulatory Requirements