compromise:

            yum-config-manager --save --setopt=xrootd-artifacts.skip_if_unavailable=true

failure: repodata/repomd.xml from xrootd-artifacts: [Errno 256] No more mirrors to try.
file:///repo/xrootd/repodata/repomd.xml: [Errno 14] curl#37 - "Couldn't open file /repo/xrootd/repodata/repomd.xml"
The command '/bin/sh -c createrepo ${XROOTDREPODIR};     awk '/\[epel\]/{ print; print "exclude=xrootd*"; next }1' /etc/yum.repos.d/epel.repo > epel.repo ; mv epel.repo /etc/yum.repos.d/epel.repo;     echo -e "[xrootd-artifacts]\nname=XROOTD artifacts\nbaseurl=file://${XROOTDREPODIR}\ngpgcheck=0\nenabled=1\npriority=1" >> /etc/yum.repos.d/xrootd.repo;     yum -y --nogpgcheck install xrootd xrootd-client xrootd-tests vim wget bind bind-utils bind-libs bind-chroot caching-nameserver' returned a non-zero code: 1
[gitlabci-docker-builder] Build already done (workaround for https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1380)
ERROR: Job failed: exit code 1