AWS Certificate Manager vs cert-manager

AWS Certificate Manager (ACM) provisions, manages and deploys public and private SSL/TLS certificates for AWS, hybrid and multicloud workloads. Certificates may cover one domain, multiple named domains, wildcard domains or combinations. Management is available through the AWS Management Console, AWS CLI and ACM APIs, with usage auditable in AWS CloudTrail logs. Amazon-issued certificates can renew automatically when DNS validation is used; otherwise ACM sends notices as expiration approaches. Public-certificate integrations include Elastic Load Balancing, Amazon CloudFront, Amazon API Gateway, AWS Elastic Beanstalk and AWS CloudFormation. AWS Key Management Service helps protect stored private keys. Customers can import third-party CA certificates and deploy them with Elastic Load Balancers, CloudFront and API Gateway; importing costs nothing. The default quota is 10 domain names per certificate, with requests up to 100. The integrated-services public-certificate plan is free and non-exportable. ACM is available on web and API platforms.

cert-manager is a free, open-source tool for obtaining and managing X.509 certificates on Kubernetes and OpenShift. It requests certificates from public or private issuers, keeps them valid, and attempts renewal before expiration. The project automates TLS certificate issuance for Kubernetes Ingress and supports private-PKI certificates for pod-to-pod mutual TLS. Documented authority options include Let’s Encrypt, HashiCorp Vault, CyberArk Certificate Manager, and private PKI. Installation can use kubectl-applied manifests, Helm, Flux, or Argo CD. Related projects include istio-csr, approver-policy, Kubernetes CSI drivers, csi-driver-spiffe, and trust-manager; trust-manager distributes X.509 trust bundles and can run independently. cert-manager publishes threat-model and hardening guidance covering secrets, RBAC, networking, and Kubernetes configuration. Its default Helm values prioritize installation ease and backward compatibility over hardened production security. The project has no LTS releases, though each release is supported until the second subsequent version.