certstrap
Tools to bootstrap CAs, certificate requests, and signed certificates
...Adapted from etcd-ca. certstrap is a very convenient app if you don't feel like dealing with OpenSSL, its myriad of options or config files. certstrap allows you to build your own certificate system. certstrap can init multiple certificate authorities to sign certificates with. Users can make arbitrarily long certificate chains by using signed hosts to sign later certificate requests, as well. If the CN contains spaces, certstrap will change them to underscores in the filename for easier use. The spaces will be preserved inside the fields of the generated files. certstrap requires either -common-name or -domain flag to be set in order to generate a certificate signing request.