When repo config contains: metalink=... but there's no 'metalink' string in the URL, dnf/librepo considers the metalink address a mirrorlist and fails on unknown URL: error: Curl error (6): Couldn't resolve host name for http://<metalink xmlns:mm0="http://fedorahosted.org/mirrormanager" xmlns="http://www.metalinker.org/" version="3.0" generator="mirrormanager" type="dynamic" pubdate="Mon, 09 Jan 2017 14:22:50 GMT">/repodata/repomd.xml [Could not resolve host: <metalink xmlns:mm0="http] (http://<metalink xmlns:mm0="http://fedorahosted.org/mirrormanager" xmlns="http://www.metalinker.org/" version="3.0" generator="mirrormanager" type="dynamic" pubdate="Mon, 09 Jan 2017 14:22:50 GMT">/repodata/repomd.xml). This is probably caused by using an obsolete librepo feature: http://rpm-software-management.github.io/librepo/lib.html#librepo.LRO_MIRRORLIST Could you replace it with LRO_MIRRORLISTURL and LRO_METALINKURL?
Clarification on why to fix this issue: 1) migrate dnf from deprecated to supported librepo features 2) support dynamically generated metalinks (I'm working on something like a mirror manager for composes) that have no 'metalink' in URL
https://github.com/rpm-software-management/dnf/pull/703
Bugs fixed in version of dnf-2.0.1-1.