Learn OPA-REGO with Real Code Examples

OPA decouples policy decisions from the application code, enabling centralized, consistent policy enforcement.

Policies are written in Rego, a declarative language designed to express complex rules and constraints.

Supports evaluation of policies for Kubernetes, CI/CD pipelines, API gateways, cloud resources, and custom applications.

OPA provides REST APIs, SDKs, and integrations for real-time policy decisions.

Enables auditing, compliance, and governance across multi-cloud and microservices environments.

Policy evaluation - enforce access, validation, or compliance rules

Rego language - declarative language for expressing rules

Data store - JSON documents for policy input and context

Decision logs - track policy decisions for auditing

Integrations - SDKs, CLI, REST API, and Kubernetes Gatekeeper

Policy - declarative rules written in Rego

Data - JSON input evaluated by policies

Decision - result of policy evaluation (allow, deny, custom)

Bundle - package of policies and data for distribution

Gatekeeper - Kubernetes integration for admission control

Policies directory with `.rego` files

Data directory with `.json` files for inputs

Bundles for versioned policy distribution

Configuration files for OPA server settings

Decision log files or endpoints for auditing

Write Rego policy rules defining allow/deny logic

Load JSON input data for context (users, resources, environment)

Deploy OPA alongside your application or as a centralized service

Query OPA via REST or SDK for policy decisions

Audit decisions and adjust policies iteratively

Beginner: Simple allow/deny policy for single service

Intermediate: Role-based access control with Rego

Advanced: Multi-service, multi-environment policy enforcement

Expert: Kubernetes admission control with complex constraints

Architect: Centralized governance for multiple clusters and pipelines

OPA vs native Kubernetes RBAC: OPA supports custom policies beyond RBAC

OPA vs traditional ACLs: OPA is declarative, centralized, and auditable

OPA vs HashiCorp Sentinel: Both are policy engines; OPA is cloud-native and more flexible

OPA vs AppArmor/SELinux: OPA handles higher-level authorization logic, not OS-level enforcement

OPA vs IAM policies: OPA provides fine-grained, programmable decisions across environments

2016 - Initial release of OPA

2017 - Rego policy language formalized

2018 - Gatekeeper project for Kubernetes integration

2019–2021 - Expanded cloud-native integrations and SDKs

2022–2025 - Enhanced performance, decision logging, and enterprise adoption

OPA - Open Policy Agent

Rego - declarative language for policies

Policy - set of rules defining allow/deny logic

Decision - result of evaluating a policy

Gatekeeper - Kubernetes admission control integration