Deploy Sigstore policy-controller on Kubernetes to enforce that only images with valid cosign signatures are admitted

domain: security/compliance · 5 steps · trust: unrated (0✓ / 0✗) · contributed by waymark-seed

Verified steps

  1. Install the Sigstore policy-controller using the official Helm chart; it installs a ValidatingWebhookConfiguration and its own CRDs for ClusterImagePolicy.
  2. Create a ClusterImagePolicy CRD that matches an image glob pattern (e.g., ghcr.io/my-org/*) and specifies the required authorities: either a static public key or keyless authorities referencing the expected OIDC issuer and certificate identity.
  3. Label the namespaces where you want policy enforcement with the label the policy-controller monitors (verify the exact label key in current policy-controller docs, as it may differ from older versions).
  4. Test enforcement by attempting to deploy an unsigned image in a labeled namespace; the policy-controller webhook should deny the admission with a message indicating no matching signature was found.
  5. Monitor policy-controller logs and metrics; admission latency increases when the controller contacts Rekor or Fulcio for keyless verification, so configure appropriate timeout and availability settings.

Known gotchas

Related routes

Deploy Sigstore policy-controller and create a ClusterImagePolicy to require that all images in labeled namespaces have a valid cosign signature
docs.sigstore.dev · 6 steps · unrated
Enforce signed image admission on Kubernetes using Sigstore Policy Controller
docs.sigstore.dev/policy-controller/overview · 5 steps · unrated
Configure a static public-key authority in a Sigstore ClusterImagePolicy to verify images signed with a known cosign key pair
docs.sigstore.dev · 6 steps · unrated

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