We occasionally see "HTTP Error 404 - Not Found" when the jenkins slave
tries to contact the EPEL mirrors. Clean up the entire /var/cache/yum/
directory and see if that helps.
Reference: https://wiki.centos.org/yum-errors
RELEASE="$(lsb_release --short -r | cut -d '.' -f 1)" # sytem release
# Clean up Jenkins slave before each build
+sudo rm -rf /var/cache/yum/*
sudo yum -y clean all
sudo yum -y remove librgw-devel librgw2 librados-devel librados3 libcephfs-devel libcephfs2
sudo yum -y autoremove