Thank you for taking the time to report this bug and helping to make
Ubuntu better.
I've confirmed that the issue is as you describe in Xenial. Trusty pre-
dates the change to locking in ntp.if-up, so is consistent. Zesty is
also consistent in using flock in both places, as is Artful. So this bug
affects only Xenial.
In order to understand the importance of this bug, please could you
explain why you're using both ntp and ntpdate? ntpdate isn't installed
by default on Xenial, and shouldn't be required in the normal case
because ntp defaults to "-g". So you could work around this bug by just
removing the ntpdate package. Is there a particular reason that this
won't work in your case?
** Also affects: ntp (Ubuntu Xenial)
Importance: Undecided
Status: New
** Changed in: ntp (Ubuntu)
Status: New => Fix Released
** Changed in: ntp (Ubuntu Xenial)
Status: New => Triaged
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to ntp in Ubuntu.
https://bugs.launchpad.net/bugs/1706818
Title:
mismatched file locking since 1:4.2.8p4+dfsg-3ubuntu1 causes race
leaving ntp dead on reboot
Status in ntp package in Ubuntu:
Fix Released
Status in ntp source package in Xenial:
Triaged
Status in ntp package in Debian:
Unknown
Bug description:
ntpdate and ntp conflict on the NTP well-known-socket. If ntp and
ntpdate 1:4.2.8p4+dfsg-3ubuntu5.5 are installed on Xenial, and there
are 2 static interfaces configured, most often we find that ntpd is
not running after a reboot.
When the ntp service is started by systemd, ntp fails to bind the NTP
socket because ntpdate is running in the background. It's intended
that ntp and ntpdate try to avoid this conflict with a lock file, but
the locking mechanism was changed in ntpdate.if-up (from lockfile to
flock), but it was not changed in ntp.init. Previously the file
locking prevented ntp from trying to start when ntpdate was running.
Not any more.
Having multiple interfaces causes a much longer period of the socket
being unavailable, because the 2 ntpdate processes will get serialized
by the lock, while the ntp service is looking for a different lock, so
it just plows right in. Attempts by netdate.if-up to stop and start
ntp seem to overlap and when the final start is invoked, systemd seems
to thing ntp is already running, though it has failed.
In 1:4.2.8p4+dfsg-3ubuntu1 the following change was made:
debian/ntpdate.if-up: Drop lockfile mechanism as upstream is using flock
now.
Looks like corresponds to rev 371 of debian/ntpdate.if-up from upstream.
This change diverged locking between ntpdate.if-up and ntp.init. This
was rectified in rev 451 of ntp.init, to use compatible locking, but
that doesn't appear in the Ubuntu version.
System Information:
lsb_release -rd:
Description: Ubuntu 16.04.2 LTS
Release: 16.04
apt-cache policy ntpdate:
ntpdate:
Installed: 1:4.2.8p4+dfsg-3ubuntu5.5
Candidate: 1:4.2.8p4+dfsg-3ubuntu5.5
Version table:
*** 1:4.2.8p4+dfsg-3ubuntu5.5 100
100 /var/lib/dpkg/status
apt-cache policy ntp:
ntp:
Installed: 1:4.2.8p4+dfsg-3ubuntu5.5
Candidate: 1:4.2.8p4+dfsg-3ubuntu5.5
Version table:
*** 1:4.2.8p4+dfsg-3ubuntu5.5 100
100 /var/lib/dpkg/status
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/1706818/+subscriptions
--
Mailing list: https://launchpad.net/~touch-packages
Post to : touch-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~touch-packages
More help : https://help.launchpad.net/ListHelp
