kube-score

Overview

kube-score is a free static analyzer for Kubernetes object definitions, built around checks that flag ways to strengthen security and resilience. It suits teams reviewing manifests before deployment, especially those who want to put the checks into a CI/CD workflow.

Its MIT license and configurable checks make it a practical fit for teams that want an adaptable Kubernetes review tool without a paid plan. Its most important constraint is that it gives its best results when related applications in a namespace are analyzed together.

Key features

Checks cover several concrete deployment concerns, including container limits, security context, probes, stable APIs, NetworkPolicy targeting, PodDisruptionBudget and Pod anti-affinity. Optional checks include matching resource requests and limits, container ports and seccomp profile configuration. This breadth makes kube-score useful for catching common configuration weaknesses; teams needing a different policy can ignore tests or enable optional ones globally or per object.

The tool works with Helm, Kustomize, static YAML, Docker and resources retrieved from an existing cluster. In CI/CD, critical errors return exit code 1, and warnings can be chosen as the failure threshold. Human-readable, JSON, CI and SARIF outputs serve different workflows; SARIF is intended to ease integration with CI platforms.

The browser demo accepts YAML or JSON. The maker says it runs entirely in the browser and sends no data to a server, making it a convenient option for inspecting definitions without uploading them to the service. For local or automated use, prebuilt binaries are available for Linux, macOS and Windows, alongside Docker, Homebrew and Kubernetes Krew installation options. Building from source requires Go 1.21 or later.

Analysis quality depends on scope: the project recommends including all applications deployed to the same namespace in the input. A narrow selection may therefore miss context that matters to the results.

Pricing

Free and open source: free. The MIT-licensed tool has no paid plans, so there is no tier that trades away features for a lower price. It is a strong fit for individuals and teams able to install and operate the tool themselves; those seeking a paid service or plan-based support should look elsewhere.

Platforms

kube-score supports Linux, macOS and Windows through prebuilt binaries, as well as Docker and browser-based use. Homebrew and Kubernetes Krew provide additional installation routes. The project is also marked for self-hosted use.

Who it's for

kube-score is best for Kubernetes teams that want configurable manifest checks in development or CI/CD, and can provide workloads together by namespace for analysis. Its open-source distribution and several installation methods suit teams comfortable choosing their own workflow. It is less suitable when the intended review scope is only isolated workloads and cannot include their namespace peers.

Pros and cons

• Pro: Security and resilience checks cover deployment settings such as probes, security context, disruption budgets and network policy targeting.
• Pro: Global or per-object configuration lets teams tune which tests run and which findings to ignore.
• Pro: CI/CD exit behavior and several output formats make results usable in automated workflows as well as direct review.
• Pro: The browser demo is described as processing YAML or JSON entirely in the browser without sending data to a server.
• Con: The recommended namespace-wide input can make preparing a representative analysis more involved than checking one object alone.
• Con: Source builds require Go 1.21 or later, a requirement for users who prefer not to use prebuilt binaries or the listed installers.

Alternatives

Conftest is another free, open-source option for readers comparing infrastructure testing tools; its listed platforms are Linux, macOS and Windows.

AWS CloudFormation is a freemium alternative for readers considering an AWS service; CloudFormation itself is free, while underlying AWS resources are billed at their own rates.

Test Kitchen is a free, open-source alternative for readers looking at infrastructure testing, with Linux, macOS and Windows support.

cfn-lint is a free, MIT-0-licensed alternative for readers evaluating a linter in the infrastructure tooling category; it supports Linux, macOS, self-hosted and Windows use.

Chef InSpec offers a free plan and trial, but its free plan is limited to non-production workloads and personal, non-commercial use.

Cinc Auditor is a free distribution of Chef InSpec for readers who can accept no formal warranties or support.

kubeconform is another free Kubernetes-focused option for readers comparing tools in this area.

OpenSCAP is a free, open-source alternative for readers considering tools in the OpenSCAP project umbrella.

For more options, see Infrastructure Testing Tools and Infrastructure as Code Security Software.

Verdict

Choose kube-score if you want free, configurable Kubernetes checks that can feed into CI/CD and multiple output workflows. Its principal advantage is practical deployment coverage without a paid tier; its main caveat is that useful results call for analyzing namespace workloads together. Look elsewhere if you cannot assemble that broader input for the workloads you need to review.