Download latest epel-release rpm from
http://download-ib01.fedoraproject.org/pub/epel/7/x86_64/ https://download-ib01.fedoraproject.org/pub/epel/7/x86_64/Packages/p/pigz-2.3.4-1.el7.x86_64.rpm
Install epel-release rpm:
# rpm -Uvh epel-release*rpm
Install pigz rpm package:
# yum install pigz
REF
https://centos.pkgs.org/7/epel-x86_64/pigz-2.3.4-1.el7.x86_64.rpm.html