00:00:33.606 Start: yum install
00:00:47.200 ERROR: Command failed. See logs for output.

and looking at logs:

DEBUG util.py:377:  Installed size: 423 M
DEBUG util.py:377:  http://download.fedoraproject.org/pub/epel/testing/7/x86_64/e/epel-rpm-macros-7-4.noarch.rpm: [Errno 14] HTTP Error 404 - Not Found
DEBUG util.py:377:  Trying other mirror.
DEBUG util.py:377:  Error downloading packages:
DEBUG util.py:377:    epel-rpm-macros-7-4.noarch: [Errno 256] No more mirrors to try.
DEBUG util.py:488:  Child return code was: 1