cert-manager is the easiest way to automatically manage certificates in Kubernetes and OpenShift clusters.
Version 1.9.1 is a bugfix release which removes an incorrect check in the Route53 DNS solver. This accidental change prevented the use of credentials derived from instance metadata or AWS pod metadata.
Thanks to @danquack and @ArchiFleKs for raising this issue, and @danquack and @JoshVanL for fixing it!