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open-policy-agent/gatekeeper

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4,228 stars·862 forks·Go·Apache-2.0·23 viewsopen-policy-agent.github.io/gatekeeper↗

Gatekeeper

Gatekeeper is a Kubernetes admission control and policy enforcement engine used to ensure cluster resources comply with organizational security and configuration standards. It intercepts API requests to validate or reject non-compliant resources before they are persisted in the cluster.

The project uses a parameterized policy library and custom resource definitions to create reusable templates and enforcement rules. It distinguishes itself through a hub-and-spoke management model, allowing a controller in a management cluster to enforce policies across separate target clusters.

Beyond admission control, the system covers compliance auditing to scan existing resources for violations and resource mutation to automatically modify incoming requests, such as updating container images or injecting metadata. It also integrates with external data providers to inform authorization decisions with real-time environmental context.

The engine provides a suite of CLI tools for policy library management, CI/CD verification, and resource expansion testing.

Features

  • Admission Webhooks - Implements Kubernetes admission webhooks to intercept and validate API requests before they are persisted in the cluster.
  • Kubernetes Policy Enforcers - Enforces defined policies on Kubernetes resources to ensure cluster configurations comply with organizational standards.
  • Request Validation and Mutation - Intercepts and evaluates Kubernetes API requests to reject non-compliant resources based on policy.
  • Kubernetes Resource Validation - Checks resources against predefined templates and custom constraints to ensure compliance before admission.
  • Admission Controllers - Intercepts and modifies Kubernetes resource requests to enforce compliance before persistence.
  • Workload Resource Validations - Rejects higher-level resources if the pods they would generate violate defined policy constraints.
  • Admission Request Validation - Evaluates resources against defined policies to deny, warn, or report violations without altering the original object.
  • Admission Resource Mutation - Modifies incoming resource objects automatically to ensure they adhere to specific organizational standards.
  • Cluster Compliance Scanning - Scans existing resources within a cluster to identify and report objects that violate defined policy constraints.
  • Cluster State Caching - Replicates resources into a local data cache so policy templates can reference the current cluster state.
  • Admission-Based Policy Enforcement - Uses the Common Expression Language (CEL) to define declarative admission control rules.
  • Cache-Based Auditing - Uses a local replication cache as the source of truth to identify constraint violations.
  • Policy-Based Resource Validation - Checks cluster resources against defined policy templates and custom constraints to prevent non-compliant configurations.
  • Resource Definition Metadata - Automatically adds labels and annotations to resource metadata based on defined matching conditions.
  • Admission Mutators - Implements mutating admission webhooks to modify incoming Kubernetes objects with custom defaults or transformations.
  • Reusable Policy Templates - Uses templates to create reusable policy libraries that are instantiated with different parameters via custom resources.
  • Admission Request Evaluation - Inspects request metadata and user information to determine compliance with organizational policies during admission.
  • Compliance Security Audits - Scans resources against defined policies to report non-compliant objects created before policy enforcement was active.
  • Parameterized Enforcement - Uses reusable policy templates and custom constraints to validate resources based on specific configuration values.
  • Kubernetes Cluster Auditing - Scans existing Kubernetes cluster resources to identify non-compliant objects and policy violations.
  • Policy Validators - Creates reusable logic to validate objects and defines the parameters required for policy instantiations.
  • Workload Template Validations - Creates expanded versions of parent resources to evaluate constraints against child objects before deployment.
  • Cluster Compliance Auditing - Periodically scans existing cluster resources against active policies to detect and report violations for pre-existing objects.
  • Resource Specification Mutators - Changes values in resource specifications or updates list entries to ensure they meet organizational standards.
  • Custom Resource Policy Definitions - Uses custom resource definitions to define reusable policy templates and specific constraint instances for deployment.
  • Data Caching - Stores retrieved values from external data providers for a set duration to lower latency and source load.
  • External Data Integrations - Integrates external data sources to enrich policy decisions with real-time environmental context.
  • Kubernetes Admission Webhook Filters - Selects which API requests trigger a webhook based on matching rules for operations, resources, and namespaces.
  • Registry Enforcement Mutations - Modifies the domain, path, or tag of container image strings to enforce the use of approved registries.
  • CI/CD Policy Gates - Provides CI/CD policy gates to test resource manifests against policies before they are applied to a cluster.
  • Cluster Management - Provides a remote cluster management model to enforce policies on separate target clusters.
  • Image Integrity Verification - Verifies the contents and origin of container images using build attestations and software bills of materials.
  • Custom Resource Definitions - Automatically creates custom resource definitions to facilitate policy configurations and enforcement.
  • Hub-and-Spoke Control Planes - Employs a hub-and-spoke control plane model to manage policies from a central cluster across multiple target clusters.
  • CEL Expression Filters - Uses Common Expression Language (CEL) to define high-performance, declarative admission control rules.
  • External Data Providers - Fetches real-time context from external HTTP services to inform authorization and validation decisions.
  • Workload Template Mutations - Modifies pod templates within workload resources to ensure child pods inherit required security settings.
  • High Availability Deployments - Distributes the engine across multiple pods and nodes to ensure high availability and resilience.
  • Image Path Rewriting - Updates the domain, path, or tag of container image strings to ensure the use of approved registries.
  • Scheduled Policy Enforcement - Schedules the frequency and batch size of resource scans to detect violations without overloading the server.
  • Kubernetes Policy Controllers - Manages policy-as-code using custom resource definitions for consistent enforcement across clusters.
  • Local Resource Caches - Synchronizes cluster state into local resource caches to perform policy evaluations without querying the API server.
  • List-Based Resource Expansion - Simulates the expansion of resource templates to verify the resulting manifests before deployment.
  • Template-Based Kubernetes Generators - Generates child resource manifests from parent workload templates to validate the final state of deployed objects.
  • Policy Library Management - Allows installing and upgrading constraint templates from a remote policy library.
  • Remote Cluster Access - Operates a controller in a management cluster while enforcing policies on separate target clusters.
  • Namespace Enforcement Exemptions - Allows excluding specific namespaces or wildcard patterns from auditing, admission, and data synchronization processes.
  • Resource Deletion Validations - Inspects and restricts requests to delete cluster resources based on defined policy constraints.
  • Resource Field Mutations - Provides the ability to change specific values within a resource specification based on customizable mutation policies.
  • Build Provenance Attestors - Uses build attestations and provenance to verify the origin and integrity of container images.
  • Fail-Closed Admission Enforcement - Rejects all resource requests when the policy engine is unavailable to prevent unvalidated changes.
  • Cloud Policy Dry-Runs - Evaluates new policy rules against existing cluster resources using dry-run modes to identify potential violations.
  • Object Constraint Validation Engines - Tests objects against templates and constraints to identify policy violations and validate resource expansion.
  • Webhook Mutation Auditors - Records which mutating webhooks modified a resource and the specific patches applied during the admission process.
  • External Policy Data Querying - Calls in-cluster HTTP services to retrieve real-time information from external registries or directories for policy decisions.
  • Metrics Exporters - Sends performance and behavioral data to external monitoring systems using configurable endpoints.
  • Resource Consumption Throttling - Adjusts concurrency limits and memory caps during evaluation to prevent CPU starvation and memory errors.
  • Violation Metrics - Exposes aggregated data on audit timestamps and violation counts via integrated monitoring systems.
  • Violation Logging - Records denied or warned policy failures to a log to assist in debugging cluster configuration issues.
  • Configuration and Policy - Enforces admission control policies within Kubernetes clusters.
  • Defending - Listed in the “Defending” section of the Awesome K8s Security awesome list.
  • Kubernetes Security - Policy enforcement for Kubernetes clusters.
  • Security and Compliance - Policy controller for enforcing admission control rules.

Star history

Star history chart for open-policy-agent/gatekeeperStar history chart for open-policy-agent/gatekeeper

How this analysis was created: This summary and feature list are AI-generated from collected project material and can contain mistakes. Stars, license and language are imported from GitHub. Inclusion does not mean that we have tested or audited this project. Check the source documentation for any feature you depend on. Learn more on our About page.

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Projects sharing features with Gatekeeper

These projects share indexed features with Gatekeeper. Shared tags can include platform or build tooling; verify the primary use case before treating a result as a replacement.
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    The Operator SDK is a framework for building, packaging, and managing custom controllers that extend the Kubernetes API. It serves as a toolset for defining new API types and implementing reconcile loops to automate the lifecycles of complex applications. The project provides specialized support for creating operators based on Helm charts or Ansible playbooks, allowing users to maintain a desired cluster state using existing automation tools. It includes a dedicated system for packaging controllers into standardized container image bundles for distribution via the Operator Lifecycle Manager.

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  • kubernetes-sigs/controller-runtimekubernetes-sigs avatar

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Frequently asked questions

What does open-policy-agent/gatekeeper do?

Gatekeeper is a Kubernetes admission control and policy enforcement engine used to ensure cluster resources comply with organizational security and configuration standards. It intercepts API requests to validate or reject non-compliant resources before they are persisted in the cluster.

What are the main features of open-policy-agent/gatekeeper?

The main features of open-policy-agent/gatekeeper are: Admission Webhooks, Kubernetes Policy Enforcers, Request Validation and Mutation, Kubernetes Resource Validation, Admission Controllers, Workload Resource Validations, Admission Request Validation, Admission Resource Mutation.

Which projects share features with open-policy-agent/gatekeeper?

Projects with overlapping indexed features include: kubernetes/kube-state-metrics — kube-state-metrics is a Kubernetes metrics exporter that generates Prometheus-compatible metrics from the current… operator-framework/operator-sdk — The Operator SDK is a framework for building, packaging, and managing custom controllers that extend the Kubernetes… kubernetes-sigs/kubebuilder — Kubebuilder is a framework and set of scaffolding tools used to build Kubernetes APIs and controllers. It functions as… kubernetes-sigs/controller-runtime — This project provides a framework for building Kubernetes operators and custom controllers. It offers a set of… fluxcd/flux2 — Flux is a Kubernetes GitOps delivery tool used to automate application deployments by synchronizing cluster state with… cerbos/cerbos — Cerbos is an open-source authorization service that provides a centralized, language-agnostic engine for managing…