Comment 4 for bug 1129696

Thank you Alexander for submitting this patch, and to Christian for catching up on old bugs. I'm reviewing Christian's merge proposal at https://code.launchpad.net/~paelzer/ubuntu/+source/ntp/+git/ntp/+merge/299122 which includes this patch but thought it would be more inclusive to discuss it directly in this bug.

There is a risk in introducing a new configuration variable in a delta in Ubuntu. If Debian don't adopt exactly the same thing, it means that we have to maintain a delta indefinitely in Ubuntu, since to then sync with Debian would mean breaking users on upgrade. In this case, Alexander will set the new NTPD_CONF variable and after a sync, Alexander will upgrade to a version where this silently stops working. Christian said "I'm not sure if this is worth a delta" and for this reason I agree.

Instead, I propose that it doesn't make sense for the system to be configured to request NTP configuration via DHCP and then not use it. So I think a more appropriate solution is to expect users who want to override ntp.conf to also disable NTP-by-DHCP in dhclient's configuration. Then /var/lib/ntp/ntp.conf.dhcp would not exist and this problem wouldn't arise. dhclient packaging should also ensure that the file is deleted when it is no longer relevant. If this is not currently possible, I think a fix should be in dhclient's package to make this easier, rather than in ntp to ignore the supplied configuration.

Alexander said "On that box, ntpd exited with an error because it had received two config files in its arguments. Not good." and I agree. Note though that with Alexander's patch, this can still happen - the patch just provides a workaround at configuration level. My proposal doesn't solve this problem either, I admit; my alternative workaround is to adjust dhclient.

So I'm proposing a "Won't Fix" for ntp in Ubuntu, and to add a task for dhclient if necessary. We can of course take whatever Debian want to do, since then we don't incur a maintenance burden. If Debian wants to add $NTPD_CONF, I have no objection. So thank you Christian for filing this in Debian. But I don't think we should add it in a delta in Ubuntu because of the pain of the divergence from Debian in this case.