Fairwinds Polaris vs terraform-compliance

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.

terraform-compliance is a free, open-source framework for security and compliance testing of Terraform infrastructure as code. It checks Terraform plan or state output against policies written as behavior-driven feature files, and it can read plan output converted to JSON. Given steps establish context, When steps filter it, and Then steps fail scenarios when conditions are unmet. The project says it works with any Terraform provider and supports Terraform versions newer than 0.12. Checks can run before deployment, in pipelines, or through git hooks. Feature files may come from a local directory or Git repository, with SSH authentication for private repositories. Installation is documented through pip, requiring Python 3.x, or Docker. CI/CD examples cover CircleCI and GitHub Actions. Controls include warning-only failures, skipped-step failures, case-sensitive matching, and resource exclusion. The tool supports policy testing, admission control, and policy reporting, but not runtime enforcement. Its MIT license permits free use.