Description of problem: 1. <dnf system-upgrade reboot> fails to upgrade. 2. entry in /var/log/messages: Failed to synchronize cache for repo »updates« 3. from /etc/yum.repos.d/fedora-updates.repo mirrors.fedoraproject.org did not get resolved. t-online returned: Die von Ihnen eingegebene Internetadresse ... konnte nicht gefunden werden. 4. next day repeat: dnf --refresh upgrade dnf system-upgrade download --releasever=27 dnf system-upgrade reboot mirrors.fedoraproject.org did get resolved! Same fail result. 5. <dnf clean all> has no effect. Downloaded rpm will be kept and not downloaded again. 6. next day some more repeats: dnf --refresh upgrade dnf system-upgrade download --releasever=27 dnf system-upgrade reboot (nb mirrors.fedoraproject.org did get resolved!) Same fail result. 7. Observation: /var/lib/dnf/system-upgrade contains several subdirectories like updates-xxxxxxxxxxxxxxxxx. 8. rm -rf /var/lib/dnf/system-upgrade/* dnf --refresh upgrade dnf system-upgrade download --releasever=27 # download all rpm again dnf system-upgrade reboot SUCCESS Version-Release number of selected component (if applicable): How reproducible: not attempted Steps to Reproduce: 1. ./. 2. ./. 3. ./. Actual results: ./. Expected results: <dnf clean all> should clean locally stored rpm Additional info: It looks like the multiple entries like /var/lib/dnf/system-upgrade/updates-xxxxxxxxxxxxxxxxx do not get handled correctly .. (after a failing name resolution??)
I think this problem is a duplicate of https://bugzilla.redhat.com/show_bug.cgi?id=1514754 , could you take a look at my comment and see if this fix the issue for you ? (the part about check_config_file_age = false)
Fwiw, had the same issue (started the upgrade process last week, download failed a few times because of local issues, finally was able to try and move forward today). On system-upgrade reboot, I was getting this error about the Updates repository not being accessible. Removing the system-upgrade cache and trying again allowed the upgrade to complete.
*** This bug has been marked as a duplicate of bug 1492036 ***