Conftest vs Sonobuoy

Conftest is a free utility for testing structured configuration data, designed for use in CI environments. It uses the Open Policy Agent Rego language to express policies, then evaluates deny, violation, and warning rules within namespaces. Configuration can be read from individual files, directories, multiple files, or standard input. Supported inputs include Kubernetes-style YAML, JSON, HCL and HCL2, Dockerfiles, Terraform-related data, JSONnet, TOML, and XML. Results can be output as plaintext, JSON, TAP, table, JUnit, GitHub, Azure DevOps, or SARIF; the GitHub outputter can annotate test results in workflows. The `conftest verify` command runs policy unit tests. Policies can be pulled from HTTPS URLs, Git repositories, and OCI registries, or pushed to compatible OCI registries. Plugins extend the CLI, with downloads available from sources including OCI, Git, HTTP/HTTPS, Mercurial, and cloud storage. Pre-commit hooks support policy workflows, and integrations are documented for CircleCI, GitHub Actions, and Tekton. Conftest is available for Linux, macOS, and Windows.

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.