Question

Your organization runs a Cloud Build pipeline that builds container images and pushes them to Artifact Registry. Security requires that only images verifiably produced by the trusted pipeline can be deployed to your production GKE cluster, and that no developer can manually push an arbitrary image that gets deployed. You have already enabled Binary Authorization on the cluster. What is the most appropriate way to complete the supply-chain control so that only pipeline-built images are admitted?

Accepted Answer

Add a Cloud Build step that creates a Binary Authorization attestation signed by a Cloud KMS key, and configure the policy to require an attestation from that attestor's public key.

Answer

Configure an Artifact Registry cleanup policy to delete any image that lacks a specific label, then let Binary Authorization admit whatever remains.

Answer

Grant only the Cloud Build service account the Artifact Registry Writer role and rely on IAM alone to block manual pushes.

Answer

Enable vulnerability scanning on Artifact Registry and set the Binary Authorization policy to block images with critical CVEs.