[Bug 229632] Re: ntpd should run niced
You are supposed to be able to use the -N (--nice) option to ntpd but upstream ntp bug report shows it doesn't work: http://bugs.ntp.org/show_bug.cgi?id=1230 Testing on 11.04 $ lsb_release -ds Ubuntu 11.04 $ uname -srv Linux 2.6.38-10-generic #46-Ubuntu SMP Tue Jun 28 15:07:17 UTC 2011 $ ntpd --version ntpd - NTP daemon program - Ver. 4.2.6p2 $ apt-cache policy ntp | egrep 'Installed|Candidate' Installed: 1:4.2.6.p2+dfsg-1ubuntu5.1 Candidate: 1:4.2.6.p2+dfsg-1ubuntu5.1 WIthout -N $ (ps alx | head -1) ; (ps alx | grep ntpd) | grep -v grep F UID PID PPID PRI NIVSZ RSS WCHAN STAT TTYTIME COMMAND 5 117 1955 1 20 0 38864 2164 poll_s Ss ? 0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -c /var/lib/ntp/ntp.conf.dhcp -u 117:126 With -N $ (ps alx | head -1) ; (ps alx | grep ntpd) | grep -v grepF UID PID PPID PRI NIVSZ RSS WCHAN STAT TTYTIME COMMAND 5 117 2915 1 20 0 38736 2096 poll_s Ss ? 0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -N -c /var/lib/ntp/ntp.conf.dhcp -u 117:126 PRI = 20 and NI = 0 in both cases. If -N did anything NI would not be 0 ** Bug watch added: bugs.ntp.org/ #1230 http://bugs.ntp.org/show_bug.cgi?id=1230 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
I thought it might be because the setpriority() call was tried after permissions were dropped but running as UID 0 doesn't change the niceness as seen in ps output $ (ps alx | head -1) ; (ps alx | grep ntpd) | grep -v grep F UID PID PPID PRI NIVSZ RSS WCHAN STAT TTYTIME COMMAND 5 0 14085 1 20 0 32404 1976 poll_s Ss ? 0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -N -c /var/lib/ntp/ntp.conf.dhcp UID = 0, PRI = 20, NI = 0 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
When run with -N and -u 117:126 Aug 19 08:14:22 linux ntpd[14158]: sched_setscheduler(): Operation not permitted Aug 19 08:14:22 linux ntpd[14158]: setpriority() error: Permission denied Aug 19 08:14:22 linux ntpd[14158]: set_process_priority: No way found to improve our priority Freaking apparmor Aug 19 08:10:04 linux kernel: [ 3150.656384] type=1400 audit(1313755804.646:29): apparmor=DENIED operation=capable parent=1 profile=/usr/sbin/ntpd pid=14085 comm=ntpd capability=23 capname=sys_nice -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
This can be added to the apparmor profile to allow -N option to work: capability sys_nice, Then run: $ sudo apparmor_parser -r /etc/apparmor.d/usr.sbin.ntpd I'm preparing an upload for this policy change now. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
ntp (1:4.2.6.p2+dfsg-1ubuntu11) oneiric; urgency=low * debian/apparmor-profile: allow sys_nice for -N option to work. More work is needed to make ntpd start niced, so not auto-closing the bug. - LP: 229632 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
I switched AppArmor for ntpd into complain mode $ sudo aa-complain /usr/sbin/ntpd Setting /usr/sbin/ntpd to complain mode. after that the ntpd -N flag started to work. $ (ps alx | head -1) ; (ps alx | grep ntpd) | grep -v grep F UID PID PPID PRI NIVSZ RSS WCHAN STAT TTYTIME COMMAND 5 117 14798 1 -100 - 38736 2096 poll_s Ss ? 0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -N -c /var/lib/ntp/ntp.conf.dhcp -u 117:126 PRI=1 NI=-100 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Oops, didn't read Jamie's posts until just now, thanks Jamie! -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Can an SRU for Lucid be done for the AppArmor modification too? -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
@Jamie given that the default ntpd configuration is to poll and the stability of the clock affects the polling interval[1] I would strongly suggest the default ntpd configuration be adjusted to run with the -N option since it would cut down on the load of NTP servers if polling was less frequent. When this scales to the world sizes it does become an issue. 1. In a nutshell when the clock is stable there is less need for ntpd to check to see the time on the upstream NTP server so it ratchets back the interval (decreases frequency) for polling by sleeping longer between checks. See ntp option maxpoll and minpoll in man ntp.conf to see the controls of the limits of the polling frequency range. See What is the best polling Interval? http://www.ntp.org/ntpfaq/NTP-s-algo.htm#Q-ALGO-POLL-BEST -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
The minimum sleep time between ntpd upstream requests is 64 seconds. With 64000 clients an ntpd server must answer one thousand requests per second. If the client ntpd clocks are very stable they will ratchet back to one request every 1024 seconds (about 17 minutes) so the same 6400 clients would only make the server process 62.5 requests per second. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Try with and with out ntpd -N option. Use ntpq -p or ntpdc -c peers to view the polling interval. Both reports have a poll column which is the sleep time in seconds between requests being sent out over the network to the upstream NTP source. The poll column will eventually change from 64 to 128 then 256 through 1024. This change can take hours or even days to occur as the clock stabilizes. Without -N I haven't seen the polling interval get to 1024 on my systems as process preemption destabilizes ntpd too much. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
@Weisi comment #7 is comment #6 in a patch file without line-breaks. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
I should probably submit this change to Debian not Canonical. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
I fully support this request. Comment #6 is a good solution. Please note that due to the line-breaks the diff won't work without mangling. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/229632 Title: ntpd should run niced To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/229632/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
** Tags added: patch -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
** Patch added: Adds an option to /etc/default/ntp to make the priority level of ntpd configurable. http://launchpadlibrarian.net/39006866/ntp-priority.patch -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
We are limited a single NTP upstream source due to political reasons outside our control and our Ubuntu ntpd loses sync periodically. I tried a number of solutions but they all failed. When I tried setting the ntpd server's nice value to negative eight it just works. Clearly the stability of ntpd is improved by reducing the number of cases in which ntpd gets preempted by scheduling. While troubleshooting this I started keeping logs with: while true ; do ntpq -p | grep name-of-upstream-time-source | logger -t ntpq -p daemon.info; done A pair of log entries showing loss of sync looks like: time remote refid st t when poll reach delay offset jitter === 2010-02-08:2010-02-08T21:53:00-05:00 *-.xxx.x 128.59.39.48 2 u 12 64 3770.5120.030 0.098 2010-02-08:2010-02-08T21:54:04-05:00 -.xxx.x 128.59.39.48 2 u 11 64 3770.5120.030 0.342 The * in the first entry indicates that the local Ubuntu host was synchronized to the remote host. The second entry does not contain the * since synchronization was lost. By changing the nicelevel of the ntpd server process to negative eight the logs no longer show any loss of synchronization. See also http://ubuntuforums.org/showthread.php?p=8801540 -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Edit: while true ; do ntpq -p | grep name-of-upstream-time-source | logger -t ntpq -p daemon.info; sleep 64; done the sleep 64 was missing. -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Scheduler preemption of ntpd causes the time on other systems to appear unstable since measurements are ruined if preemption occurs during them. -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
You can edit your defaults file to run ntpd at maximum priority: --- /etc/default/ntp~ 2009-12-04 13:07:15.0 -0500 +++ /etc/default/ntp2010-02-09 17:56:07.0 -0500 @@ -1 +1 @@ -NTPD_OPTS='-g' +NTPD_OPTS='-g -N' -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Actually the -N argument does nothing. -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
[Bug 229632] Re: ntpd should run niced
Hacking the startup script seems to be the best temporary fix. -- default-intrepid-ntp-init-script 2010-02-09 15:01:43.255277872 -0500 +++ /etc/init.d/ntp 2010-02-09 15:02:48.0 -0500 @@ -57,7 +57,7 @@ exit 1 fi lock_ntpdate - start-stop-daemon --start --quiet --oknodo --pidfile $PIDFILE --startas $DAEMON -- -p $PIDFILE -u $UGID $NTPD_OPTS + start-stop-daemon --start --quiet --oknodo --pidfile $PIDFILE --startas $DAEMON --nicelevel -8 -- -p $PIDFILE -u $UGID $NTPD_OPTS status=$? unlock_ntpdate log_end_msg $status -- ntpd should run niced https://bugs.launchpad.net/bugs/229632 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
