cert-manager adds certificates and certificate issuers as resource types in Kubernetes clusters, and simplifies the process of obtaining, renewing and using those certificates.
It can issue certificates from a variety of supported sources, including Let's Encrypt, HashiCorp Vault, and Venafi as well as private PKI.
It will ensure certificates are valid and up to date, and attempt to renew certificates at a configured time before expiry.
It is loosely based upon the work of kube-lego and has borrowed some wisdom from other similar projects such as kube-cert-manager.
This website provides the full technical documentation for the project, and can be used as a reference; if you feel that there's anything missing, please let us know or raise a PR to add it.