kube-score

Overview

kube-score is a static analyzer for Kubernetes object definitions that recommends changes to improve security and resilience. It is best suited to teams reviewing deployment configuration in development or CI/CD; it is less useful when related applications in a namespace cannot be analyzed together.

Its appeal is a focused set of configurable checks, several output formats and a free MIT license. The central trade-off is scope: it assesses Kubernetes definitions, and its results are strongest when input includes all applications deployed to the same namespace.

Key features

Checks address concrete deployment concerns, including container limits, security context, probes, stable APIs, NetworkPolicy targeting, PodDisruptionBudget and Pod anti-affinity. Optional checks cover matching resource requests and limits, container ports and seccomp profile configuration. Teams can ignore tests or enable optional ones globally or per object, making it possible to tune the analysis to a project rather than accept every check as mandatory.

kube-score supports workflows built around Helm, Kustomize, static YAML files, Docker and resources retrieved from an existing Kubernetes cluster. In CI/CD, critical errors return exit code 1; teams can instead set warnings as the failure threshold. Human-readable, JSON, CI and SARIF formats suit different consumers, with SARIF intended to ease integration with CI platforms.

The online demo accepts Kubernetes YAML or JSON and, according to the maker, processes it entirely in the browser without sending data to a server. That makes it a convenient option for inspecting definitions without installing the command-line tool, while the privacy claim is specific to the browser demo.

Pricing

Free and open source: free. The MIT-licensed tool has no paid plans listed, so there is no upgrade tier to unlock additional checks or workflows. It suits individual users and teams comfortable adopting open-source software; organizations seeking a paid plan should look elsewhere.

There is no free trial because the tool is free. Building from source requires Go 1.21 or later, though prebuilt binaries and other installation options avoid that build requirement.

Platforms

Prebuilt binaries are available for Linux, macOS and Windows. Docker, Homebrew and Kubernetes Krew are also installation options. The browser demo runs in the browser and accepts YAML or JSON. For a source build, Go 1.21 or later is required.

Who it's for

kube-score fits Kubernetes teams that want repeatable configuration checks before deployment, especially those able to analyze a namespace's applications together and act on findings in CI/CD. Its selectable checks and output formats also suit teams that need to tailor results for different objects or pipeline consumers. It is a narrower fit for readers looking for a general-purpose infrastructure testing tool rather than analysis of Kubernetes object definitions.

Pros and cons

Pros: The MIT license and free price make it accessible without a paid-plan decision.

Pros: Checks span security and resilience concerns, with options to ignore or enable tests globally or per object.

Pros: CI/CD exit behavior and four output formats support both automated gates and different reporting workflows.

Pros: The browser demo provides a way to submit YAML or JSON while keeping processing in the browser, according to the maker.

Cons: Results are best when all applications deployed to the same namespace are included, which can complicate analysis when manifests are split across teams or workflows.

Cons: Building from source requires Go 1.21 or later; users who do not want that dependency need to use another installation option.

Alternatives

For broader infrastructure-testing options, see Infrastructure Testing Tools. For tools focused on securing infrastructure as code, browse Infrastructure as Code Security Software.

Chef InSpec is a freemium alternative with a free plan for unlimited-duration, non-production workloads and personal, non-commercial use, plus a 30-day trial. Choose it when those terms and its API, Linux, macOS, self-hosted or Windows platform support better fit your needs.

Conftest is a free, Apache-licensed option for Linux, macOS and Windows. Consider it when those platforms and its open-source terms suit your choice.

kubeconform is a free tool for Linux, macOS, self-hosted environments and Windows, with no paid plans or usage limits stated on its official site. Consider it if that platform range is a better fit.

Test Kitchen is a free, Apache-licensed option installable from RubyGems, system packages or Cinc/Chef Workstation. Pick it if those installation routes suit your environment.

AWS CloudFormation is free as a service, but underlying AWS resources are billed at their own rates. Consider it if that service model fits your needs.

Sonobuoy is a free, open-source alternative.

Terratest is an open-source project under the Apache 2.0 License, built by Gruntwork.

TFLint is a free, open-source command-line Terraform linter for Linux, macOS, self-hosted environments and Windows. Consider it when Terraform linting is the need rather than Kubernetes object analysis.

Verdict

Choose kube-score if you want free, configurable checks for Kubernetes definitions that can run in CI/CD, particularly when you can analyze namespace applications together. Its focused scope and useful pipeline outputs make it a practical fit for that job; look elsewhere if you need a broader infrastructure-testing tool or cannot provide the related namespace definitions for the strongest results.