cfn-lint vs Sonobuoy

cfn-lint is a free, open-source validator for AWS CloudFormation YAML and JSON templates. It checks templates against resource provider schemas and applies additional rules, including validation of property values and best practices. AWS Serverless Application Model templates are processed after transformation with AWS SAM. Users can configure built-in checks through command-line options, configuration files, or CloudFormation template metadata, and can add custom rules. Results can be emitted as quiet, parseable, JSON, JUnit, pretty, or SARIF output. Installation options documented by the project include pip, Homebrew for macOS, and Docker; supported Python versions are 3.10 through 3.14. Listed integrations include Atom, Emacs, NeoVim/Vim, Sublime, Visual Studio Code, IntelliJ IDEA, GitHub Actions, and pre-commit. The project treats complex template-value validation as best effort and does not fail merely because it cannot interpret or translate a value. The repository identifies its license as MIT No Attribution, and the plan costs nothing.

Sonobuoy is a free, open-source diagnostic tool for examining Kubernetes cluster state with non-destructive configuration tests. It can check a cluster against official Kubernetes specifications and produce diagnostics for troublesome workloads. Teams can build plugins for additional tests and data collection. Its default plugins run Kubernetes end-to-end tests and gather systemd logs; community options include CIS Benchmarks, Kube-hunter, Who-can, Cluster-Inventory, and Reliability Scanner. It is cluster agnostic and officially supports the latest three minor Kubernetes versions. Beginning with version 0.20, it supports Kubernetes 1.17 or later. Sonobuoy can run end-to-end tests with custom registries in air-gapped deployments. It requires an active Kubernetes cluster and an admin kubeconfig, and can be installed from binary releases or through Homebrew on macOS. The project provides community support through GitHub. Its documentation warns that default settings need explicit hardening, and notes that some logging and retrieval commands can fail on Docker Desktop Kubernetes.