On Tue, Jul 28, 2020 at 10:58 AM John M. Harris Jr <johnmh@xxxxxxxxxxxxx> wrote: > > On Tuesday, July 28, 2020 5:11:31 AM MST Lennart Poettering wrote: > > On Mo, 27.07.20 09:20, Neal Gompa (ngompa13@xxxxxxxxx) wrote: > > > > > > > That *is* what will happen. In this scenario, systemd-resolved creates > > > a file in /run that is populated with the required information for > > > applications to request name resolution from resolved through the > > > standard DNS protocol. The /etc/resolv.conf file becomes a symlink to > > > the file in /run so that the file in /etc is stable and regenerating > > > the file in /run won't cause issues for package management. This > > > system has been in use *already* for a while now in other > > > distributions (see Debian and resolvconf(8), which systemd-resolved > > > replaced in Ubuntu). > > > > > > > > > > > > The only thing this mechanism breaks is applications trying to *write* > > > to the resolv.conf file, because systemd-resolved will just blow away > > > those changes right after. If you want to modify DNS settings, you > > > need to configure systemd-resolved itself, either through > > > NetworkManager (as we will recommend) or directly through > > > systemd-resolved's configuration interface (if not using NetworkManager). > > > > > > That's not quit true: if you replace th /etc/resolv.conf symlink with > > a file of your own choosing, then resolved will not muck around with > > that, and not modify it anymore. instead, it will start to *read* it > > and use the data. i.e. depending on symlinks vs. file it either > > provides or consumes the data in it. > > > > Thus admin-provided configuration in /etc/resolv.conf takes precedence > > over the stuff systemd-resolved puts there, as long as the admin > > properly replaces the symlink. If the admin doesn't replace the > > symlink and writes to it naively, i.e. where it points then it will > > make changes to files in /run/systemd/ (because that's where the > > symlink points to), i.e. files clearly owned by systemd, and > > systemd-resolved will brutally overwrite them whenever it feels the > > need to. > > To prevent brutally overwriting configuration, it would be best not to replace > /etc/resolv.conf with a symlink on upgrade, ignoring user configuration, but > to do so on all new installs. > We can be smart here and replace the file when we detect that it's managed by NetworkManager. Otherwise we won't replace it. -- 真実はいつも一つ！/ Always, there's only one truth! _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
