Deploying Kyverno For Kubernetes Policy Enforcement

In this article, we will explore the deployment and configuration of Kyverno as a native Kubernetes policy engine. We will delve into how it can be used with Fawkes IDP to enforce critical security, standardization, and governance policies, ensuring compliance and platform integrity.

Feature Story: Kyverno Policy Enforcement Engine Deployment

Story: Deploy Kyverno to Implement Native Kubernetes Policy-as-Code

As a Platform Engineer, the goal is to deploy and configure Kyverno as the native Kubernetes policy engine. This will enable Fawkes IDP to enforce critical security, standardization, and governance policies (Policy-as-Code) across all application deployments, ensuring compliance and platform integrity. Kyverno's ability to act as a dynamic admission controller makes it invaluable for modern Kubernetes environments that prioritize security and consistency.

Understanding the Current and Desired States

The CURRENT STATE involves enforcing security and standardization primarily through CI pipeline checks before deployment. However, post-deployment compliance, such as runtime security context, mandatory labels, and resource limits, is inconsistent and relies heavily on manual oversight by cluster administrators. This manual process is prone to errors and doesn't scale effectively as the number of applications and deployments grows. Security and operational consistency are critical for any organization, and relying on manual checks creates gaps that can be exploited.

The DESIRED STATE is to have Kyverno deployed cluster-wide, acting as a dynamic admission controller. This means that Kyverno will automatically intercept and evaluate requests to the Kubernetes API server, enforcing policies in real-time. The initial policies will be designed to enforce minimum security standards, ensure proper integration with platform services like Vault and Ingress, and apply standardization through automatic mutation and label generation. This proactive approach to policy enforcement significantly reduces the risk of misconfigurations and security vulnerabilities. Imagine a world where every deployment adheres to best practices, and compliance is built-in, not bolted on. This is the promise of Kyverno.

Impacted Repositories and Design Documentation

The implementation of Kyverno will impact several key repositories and documentation, ensuring that the changes are well-integrated and documented for future reference. The main areas of impact include:

• https://github.com/paruff/fawkes/tree/main/platform/apps/kyverno: This will house the new Helm chart and deployment manifests for the Kyverno core, providing a standardized and repeatable way to deploy and manage Kyverno within the cluster.
• https://github.com/paruff/fawkes/tree/main/platform/policies/mandatory-security.yaml: This directory will contain the cluster-wide policies focused on enforcing mandatory security requirements, such as Pod Security Admission (PSA) standards and image registry whitelists. These policies are crucial for maintaining a secure and compliant environment.
• https://github.com/paruff/fawkes/tree/main/platform/policies/mutation-policies.yaml: This new directory will be dedicated to platform standardization policies. These policies will handle tasks like automatically adding labels and setting default configurations, ensuring consistency across all deployments.
• https://github.com/paruff/fawkes/blob/main/docs/architecture.md: The existing architecture documentation will be updated to include Kyverno in the Security/Governance section, providing a clear overview of how Kyverno fits into the overall platform architecture.
• A new Architecture Decision Record (ADR) will detail the initial set of mandatory policies, including PSA enforcement levels and image registry whitelists. This ADR will serve as a critical reference point for understanding the rationale behind the initial policy set.

By addressing these areas, we ensure a comprehensive integration of Kyverno, making it a seamless and well-documented part of the Fawkes IDP platform.

Kyverno Policy Enforcement Workflow

The Kyverno policy enforcement workflow is a streamlined process designed to ensure that all deployments meet the defined security, standardization, and governance requirements. This workflow is critical for maintaining a consistent and secure Kubernetes environment. When a resource is submitted to the Kubernetes API, Kyverno intercepts the request and applies its policies. This happens in real-time, ensuring that only compliant resources are admitted into the cluster. Kyverno policies can be designed to validate, mutate, or generate resources, providing a flexible and powerful way to manage Kubernetes configurations.

The workflow can be broken down into the following key steps:

1. Resource Submission: A developer or automated system submits a resource definition (e.g., Pod, Deployment, Service) to the Kubernetes API server using tools like kubectl. This is the initial trigger for the policy enforcement process.
2. Admission Controller Interception: Kyverno, acting as a dynamic admission controller, intercepts the incoming request. Admission controllers are Kubernetes components that intercept requests to the API server prior to persistence of the object, but after the request is authenticated and authorized.
3. Policy Matching: Kyverno evaluates the resource against its configured policies. Policies are defined using Kubernetes manifests and specify conditions and actions to be taken on matching resources. Kyverno uses a powerful pattern-matching engine to determine which policies apply to the submitted resource.
4. Policy Execution: Based on the policy type (validation, mutation, or generation), Kyverno takes the appropriate action:
   • Validation: Kyverno checks if the resource meets the policy requirements. If the resource violates a policy, the request is denied, and an error message is returned to the user.
   • Mutation: Kyverno modifies the resource to comply with the policy. This could involve adding labels, setting resource limits, or injecting sidecar containers.
   • Generation: Kyverno creates new resources based on the policy. This is often used to create default network policies, resource quotas, or other supporting resources.
5. Response and Reporting: Kyverno responds to the API server with the outcome of the policy evaluation. If the resource is valid or has been successfully mutated, the request is allowed to proceed. If the resource is invalid, the request is rejected. Kyverno also generates reports detailing policy violations and actions taken, providing valuable audit and monitoring information.

By implementing this workflow, Kyverno ensures that all resources deployed in the Kubernetes cluster adhere to the defined policies, promoting security, consistency, and compliance. The real-time nature of this enforcement is a significant advantage, as it prevents non-compliant resources from ever being deployed, reducing the risk of vulnerabilities and misconfigurations.

Acceptance Criteria

Kyverno's deployment must demonstrate enforcement, modification, and reporting capabilities to be considered successful. These capabilities are essential for ensuring that Kyverno effectively manages and secures the Kubernetes environment. Enforcement capabilities ensure that policies are actively applied, preventing non-compliant resources from being deployed. Modification capabilities allow Kyverno to automatically adjust resources to meet policy requirements, ensuring consistency and standardization. Reporting capabilities provide visibility into policy violations and actions taken, enabling auditing and continuous improvement.

These scenarios cover a range of Kyverno's capabilities, from basic validation to complex mutation and generation. By meeting these criteria, we can be confident that Kyverno is functioning correctly and providing the intended benefits. Each scenario is designed to test a specific aspect of Kyverno's functionality, ensuring that the platform is robust and reliable.

Definition of Done (DoD)

The Definition of Done (DoD) outlines the criteria that must be met for the Kyverno deployment to be considered complete. This ensures that the solution is not only implemented but also tested, documented, and ready for use. A clear DoD is essential for maintaining quality and consistency in software development projects. By establishing these criteria upfront, we ensure that all stakeholders have a shared understanding of what constitutes a finished product.

• [ ] Code Implementation: Complete according to technical directives. This includes writing the necessary code to deploy and configure Kyverno, as well as defining the initial set of policies. The code should be clean, well-documented, and adhere to established coding standards.
• [ ] Testing:
  • [ ] New unit tests added and passing. Unit tests verify the functionality of individual components, ensuring that they work as expected. These tests are crucial for catching bugs early in the development process.
  • [ ] Mutation/Validation E2E Test: Automated tests confirm that a known insecure manifest is correctly blocked (Validation), and a known incomplete manifest is correctly standardized (Mutation). End-to-end (E2E) tests simulate real-world scenarios, ensuring that the entire system works together correctly. These tests are particularly important for verifying Kyverno's policy enforcement capabilities.
  • [ ] Acceptance Criteria scenarios validated via integration tests or local environment validation. Integration tests verify the interaction between different components of the system. Validating the acceptance criteria ensures that the solution meets the defined requirements.
• [ ] Configuration: New environment variables documented in .env.example and applied to Helm values files. Proper configuration management is essential for ensuring that the solution can be deployed and managed consistently across different environments.
• [ ] Documentation:
  • [ ] Inline GoDoc/comments added to all public functions. Clear and concise documentation is crucial for maintaining and extending the solution in the future. Inline comments provide context and explanations within the code itself.
  • [ ] README.md updated with relevant usage or configuration instructions. The README file serves as the primary entry point for users, providing essential information about how to use and configure the solution.
  • [ ] Kyverno Policy Guide: Detailed documentation explaining the mandatory, mutating, and optional policies available to developers. This guide will help developers understand how to leverage Kyverno policies effectively, ensuring that they can deploy applications that meet the required security and compliance standards.
• [ ] Review: Code is ready for a peer review and a Pull Request (PR) has been opened. Peer reviews help identify potential issues and ensure that the code meets quality standards. Opening a PR signals that the code is ready for integration into the main codebase.
• [ ] Monitoring/metrics updated to confirm business value delivered. Monitoring and metrics provide visibility into the performance and effectiveness of the solution, allowing us to track its impact and identify areas for improvement.

By adhering to this Definition of Done, we can ensure that the Kyverno deployment is a high-quality, well-documented, and fully functional solution.

Technical Notes / Constraints

Several technical notes and constraints must be considered during the Kyverno deployment to ensure its effectiveness and compatibility with the existing infrastructure. These considerations are crucial for avoiding potential issues and ensuring that Kyverno is configured optimally. Failing to address these constraints can lead to performance bottlenecks, security vulnerabilities, or conflicts with other systems.

• Deployment Mode: Kyverno must be deployed in Enforce mode for critical security policies (e.g., Pod Security Standards) and Audit/Mutate mode for non-critical standardization policies (e.g., adding labels). Enforce mode actively blocks non-compliant resources, while Audit/Mutate mode allows resources to be deployed but either logs violations or modifies the resources to comply with policies. Choosing the appropriate mode for each policy is essential for balancing security and operational flexibility.
• Initial Policies: The initial policy set must include: 1) Enforcing Pod Security Admission standards, 2) Mutating deployments to include standardized platform labels (app.fawkes.idp/service-name), and 3) Mutating services to use the platform's Ingress Class. These policies provide a baseline level of security and standardization, ensuring that all deployments adhere to basic requirements. Pod Security Admission (PSA) standards, for example, define different levels of security restrictions for Pods, helping to prevent common security vulnerabilities.
• Avoid Duplication: Ensure Kyverno policies do not conflict with or duplicate security checks already performed by the CI Security Scan (SonarQube story). Duplicating checks can lead to unnecessary overhead and potential conflicts. It's important to have a clear understanding of the existing security checks and design Kyverno policies to complement, rather than duplicate, those checks. This requires coordination between different teams and tools involved in the software delivery process.

By carefully considering these technical notes and constraints, we can ensure that the Kyverno deployment is successful and provides the intended benefits without introducing new issues or conflicts.

Labels / Project Fields

Proper labeling and project fields are essential for organizing and tracking the Kyverno deployment story. These metadata elements help categorize the work, prioritize tasks, and provide context for future reference. Consistent labeling practices are crucial for effective project management and collaboration. Without proper labels, it can be difficult to track progress, identify dependencies, and ensure that all aspects of the project are addressed.

• Labels: type:story, priority:high, platform, security, governance, policy-as-code
• Project: fawkes

The labels provide a concise way to categorize the story, indicating its type, priority, and the areas it impacts. The type:story label identifies this as a user story, while priority:high indicates its importance. The platform, security, governance, and policy-as-code labels highlight the key domains that this story addresses, making it easier to filter and track related work. Assigning the story to the fawkes project provides additional context, indicating the overall project to which this work belongs.

These labels and project fields ensure that the Kyverno deployment story is well-organized and easily discoverable, contributing to the overall success of the project. Effective metadata management is a key component of any well-run software development project.

Conclusion

Deploying Kyverno as a native Kubernetes policy engine is a significant step towards enhancing security, standardization, and governance within the Fawkes IDP platform. By enforcing policies as code, Kyverno ensures that all deployments adhere to best practices, reducing the risk of misconfigurations and security vulnerabilities. The real-time nature of Kyverno's policy enforcement provides a proactive approach to security, preventing non-compliant resources from ever being deployed. With its robust features and flexible configuration options, Kyverno is a powerful tool for managing and securing modern Kubernetes environments. For more information on Kyverno and its capabilities, visit the official Kyverno website.