Fairwinds Polaris vs Kyverno

Fairwinds Polaris is an open source policy engine for validating and remediating Kubernetes resource configuration. It includes more than 30 built-in policies, and teams can add their own using JSON Schema. Checks cover security practices such as least privilege, privilege escalation, root execution, and host IPC or PID settings, along with resource requests and limits, readiness and liveness probes, and image tags. Polaris can run as a dashboard, an admission controller, or a command-line tool for checking local YAML files in CI/CD. Its validating webhook rejects workloads that trigger danger-level checks; warning-level findings pass and appear in the dashboard or webhook logs. A mutating webhook or command-line run can automatically remediate supported issues, including missing limits and probes and some unsafe security settings. The dashboard can audit local files or connect to a live cluster, and can be installed with kubectl or Helm. The validating webhook requires a valid TLS certificate. Polaris is free and runs on Linux, macOS, Windows, web, and self-hosted environments.

Kyverno is a free, open-source policy engine for defining and enforcing policy as code in Kubernetes. Its stable policy types can validate, mutate, generate or delete resources, and verify container image signatures and attestations. The Kyverno CLI can test policies against Kubernetes resource manifests in CI before they are applied to a live cluster. Documentation describes use with Helm, YAML manifests, GitHub Actions and GitOps tools such as ArgoCD. Kyverno is installed in a Kubernetes cluster; Helm is recommended for production, and YAML manifests are also available. A standard installation requires an admission controller, while background, reports and cleanup controllers are optional. Production installations should use high availability mode. The project supports CEL-based policy types and describes applying Kubernetes-style policies outside Kubernetes as part of its mission. Its webhooks default to fail-closed, so matching requests can fail if the API server cannot reach Kyverno. The project documents Cosign signatures for images and manifests, and lists CLI binaries for Linux, macOS and Windows.