Easy install works on Ubuntu 18.04 with python3. With CentOS7 it was a bit more complicated, the last time I tried. You first have to install all the dependencies that easy install misses.
Try to run this first:
yum install epel-release && yum update
yum groupinstall "Development Tools" # equivalent of build-essential
yum install git ntp wget
yum install https://centos7.iuscommunity.org/ius-release.rpm
yum install python36u python36u-devel python36u-pip