Easy-RSA 3
The current Easy-RSA codebase is 3.x, which is a full re-write compared to the 2.x release series. Downloads are available as GitHub project releases (along with sources.)
Looking for a quick OpenVPN howto guide? Read EasyRSA3-OpenVPN-Howto
Additional Easy-RSA 3 documentation can be found in the project downloads or using the online display through GitHub below:
Easy-RSA v2
For people using the prior version of Easy-RSA, 2.x, the official OpenVPN Howto document contains a PKI section that functions as the howto for the v2 codebase.
If you're using Easy-RSA v3, please see the above section for resource links.
Upgrade from Easy-RSA v2 to Easy-RSA v3
Easy-RSA v3 now has tool for upgrading your PKI From Easy-RSA v2 to v3.
There is also an extension utility called EasyTLS which can be used along side Easy-RSA v3.
EasyTLS is used to build TLS keys and inline files for use with OpenVPN.
See: https://github.com/TinCanTech/easy-tls