I have tried to install erpnext using the easy install process in a virtual machine. It will have an error in connecting mariadb 10.2 server. The problem in default mariadb 10.2 does NOT allow you to connect using localhost but using 127.0.0.1 it will connect successfully. The issue is the ansible installation script in erpnext is using localhost to connect mariadb.
Workaround: I install first mariadb 10.0 before I run the easy install scriipt.
I have created an issue.