Comment 34 for bug 1723350

Thanks for searching out this info!
I grepped through all logs for "inot" and found no match (only the initial inotify setup). So it seems sssd was not notified via inotify of the change.
That matches the behaviour that "strace" showed that "127.0.0.1" instead of "127.0.0.53" was queried.

So either, there is a race (resolv.conf symlink target changed right between sssd reading it and inotify watch being activated, if this is the order in which things happen?) or systemd-resolved somehow manages to change resolv.conf in a way that inotify does not alert on.

For example, it seems that if I do the following:
$ touch old_resolv
$ touch new_resolv
$ ln -s old_resolv resolv
and now I setup an inotify watch on resolv, and perform:
$ ln -sf new_resolv resolv
Then effectively, resolv is changed (since the symlink target changed) but inotify does not see it.

Not sure if this is what systemd-resolved is doing, but it's not unlikely...