Is longhorn part of rke2 or has anyone used longhorn on rke2?

I did it couple of releases ago and it did work. I am not sure what you mean by "part of rke2"? Longhorn is available in "Apps"... There are some requirements at the OS level that you will have to meet: https://longhorn.io/docs/1.3.0/deploy/install/

thanks. At first i thought rke2 was a bundle of preconfigured features. Disregard - i wasnt sure if it was already configured with a specific storage facility.