trust is an operator for distributing trust bundles across a Kubernetes cluster. trust is designed to complement cert-manager by enabling services to trust X.509 certificates signed by Issuers, as well as external CAs which may not be known to cert-manager at all.
We'd encourage you to test it and we'd hope it'll be useful; just be prepared for breaking changes!
Please follow the documentation at cert-manager.io for installing and using trust.