Policy Enforcement
Policy enforcement tools help ensure compliance and security standards across your Kubernetes clusters. They act as automated security guards that validate and enforce rules before resources are created or modified.
What is Policy Enforcement?
Policy enforcement uses admission controllers to validate Kubernetes resources against defined policies. Policies are written as code, making them:
- Version controlled - Policies live in Git
- Testable - Policies can be unit tested
- Reusable - Share policies across clusters
- Automated - Enforced automatically, no manual review needed
flowchart TD
A[API Request] --> B[Authentication]
B --> C[Authorization]
C --> D[Policy Engine]
D --> E{Policy Check}
E -->|Pass| F[Resource Created]
E -->|Fail| G[Request Rejected]
D --> H[Optional: Mutate]
H --> F
style A fill:#e1f5ff
style D fill:#fff4e1
style G fill:#ffebee
style F fill:#e8f5e9
Why Policy Enforcement Matters
Manual security reviews don’t scale. Policy enforcement provides:
- Consistency - Same rules applied everywhere
- Speed - Instant feedback, no waiting for reviews
- Compliance - Automated compliance checking
- Prevention - Stop misconfigurations before they’re deployed
Policy Enforcement Tools
OPA/Gatekeeper
Open Policy Agent (OPA) is a general-purpose policy engine. Gatekeeper is a Kubernetes-specific implementation that uses OPA:
- General purpose - Works beyond Kubernetes
- Powerful language - Rego policy language
- Flexible - Can validate and mutate resources
Kyverno
Kubernetes-native policy engine designed specifically for Kubernetes:
- Kubernetes-native - Policies are Kubernetes resources
- Easy to learn - YAML-based, no special language
- Built-in features - Image verification, resource generation
Common Policy Types
Security Policies
- Require non-root containers
- Block privileged containers
- Enforce resource limits
- Require security contexts
Compliance Policies
- Require specific labels
- Enforce naming conventions
- Require annotations
- Block deprecated APIs
Best Practice Policies
- Set default resource requests
- Require health checks
- Enforce image pull policies
- Validate resource quotas
Best Practices
- Start simple - Begin with basic policies, add complexity gradually
- Test policies - Test policies in non-production first
- Document policies - Explain why each policy exists
- Version control - Store policies in Git
- Monitor violations - Track what’s being blocked
- Regular reviews - Update policies as requirements change
Topics
- OPA/Gatekeeper - Open Policy Agent and Gatekeeper
- Kyverno - Kubernetes-native policy engine
- Policy Patterns - Common policy patterns
See Also
- Admission Control - How admission control works
- Webhooks - Custom admission webhooks
- Pod Security Standards - Built-in security policies