“[Errno -1] repomd.xml does not match metalink for epel” when trying to run yum update in CentOS 7.5

When yum installs packages, it references different EPEL mirror repositories depending on where the builder is. If only a few jobs fail in `yum update` or `yum install` with the following error messages when you run parallel jobs, it means a mirror repository is lagging behind the primary and it causes inconsistent versioning.

https://dl.fedoraproject.org/pub/epel/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.
https://iad.mirror.rackspace.com/epel/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.
https://mirror.umd.edu/fedora/epel/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.
https://mirror.vcu.edu/pub/gnu%2Blinux/epel/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml does not match metalink for epel
Trying other mirror.

The solution is to disable the use of the EPEL mirror. You can disable it by uncommenting the baseurl lines and commenting out the mirrorlist lines in/etc/yum.repos.d/epel.repo.

$ sed -i -e 's/^#baseurl=/baseurl=/' -e 's/^metalink=/#metalink=/' /etc/yum.repos.d/epel.repo