Re: [systemd-devel] timers always run when time changes
On Fri, 01.05.15 09:35, Likang Wang (labor...@gmail.com) wrote: Hi all, I hava a timer with the fellowing setting: # cat /lib/systemd/system/updateimage.timer [Unit] Description=Update image DefaultDependencies=false [Timer] OnCalendar=*-*-* 02:00:00 Persistent=false [Install] WantedBy=multi-user.target And I want the timer call the same-name service only on 02:00:00 daily. The entire system is running on an embedded box, and the system time will be set to 2008-01-01 00:00:00 after every reboot. My app running on the box will get the real time from my server and update time on the box after every booting.(I could not use NTP or systemd-timesyncd for some other reason) Here is my problem. When my app set the system time to real time, systemd will wake up the updateimage.timer and run the updateimage.service no matter what time it it now.The log looks like this: Jan 1 08:14:00 systemd[1]: xx.service: cgroup is empty Apr 30 21:04:00 systemd[1]: Time has been changed Apr 30 21:04:00 systemd[1]: Set up TFD_TIMER_CANCEL_ON_SET timerfd. Apr 30 21:04:00 systemd[1]: Timer elapsed on updateimage.timer Apr 30 21:04:00 systemd[1]: Trying to enqueue job updateimage.service/start/replace Apr 30 21:04:00 systemd[1]: Installed new job updateimage.service/start as 9269 What I want is the timer and the same-name service only run exactly on 02:00:00 daily, but not when time changes. What should I do? Well, the way this works is that when the timer unit is started systemd determines the next time the unit shall elapse. Given that your clock is initialized to 2008-01-01 00:00:00 this means it will calculated 2008-01-02 02:00:00. Then, when you make the clock jump, and it becomes 2015-04-30 21:04:00 systemd notes that the calculated elapsing time is now already in the past and immediately dispatch the timer unit. In most cases this is arguably what you want since it gives you the guarantee that your service is always run less time ago than the interval you specified -- on the wallclock. Now I can see that in you case this behaviour might not be advisable. Two suggestions: - consider using systemd-timesyncd for time synchronization. It implements sNTP and will sync the last known time to disk every time it gets an sNTP sync or the system is shut down. At boot it uses that time to reinitialize the clock, as early as possible, before NTP is done. THis will give you monotonic time which should solve your probelm. - Introduce some flag file to conditionalize your service with ConditionPathExists= or so, so that it is only started when the clock was set at least once... Each time you sync the clock, create that file. if it is missing you hence know that the clock is not ready for syncing on... Lennart -- Lennart Poettering, Red Hat ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] timers always run when time changes
On Thu, Apr 30, 2015 at 6:35 PM, Likang Wang labor...@gmail.com wrote: Hi all, The entire system is running on an embedded box, and the system time will be set to 2008-01-01 00:00:00 after every reboot. My app running on the box will get the real time from my server and update time on the box after every booting.(I could not use NTP or systemd-timesyncd for some other reason) Does the service file for this custom time syncing service have the directive `Before=time-sync.target` ? If it does, are you sure that when it is considered running by systemd that the time has indeed been synced? Cheers, -- Cameron Norman ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] timers always run when time changes
The custom time syncing service file does not have Before=time-sync.target. In fact, not only when the time changes by the custom time syncing service ,but also when I set the time manually by date -s 2015-05-01 11:08:00, the timer and the same-name service will run. Here is the custom time syncing service file: #cat /lib/systemd/system/XX.service [Unit] Description=XXX Daemon After=ppp.service [Service] Type=simple ExecStart=/usr/lib/XX/xx/bin/xx Restart=always Here is the log when I set the time manually by date -s 2015-05-01 11:08:00 #systemctl status updateimage.timer -l — updateimage.timer - Update image Loaded: loaded (/lib/systemd/system/updateimage.timer; disabled) Active: active (waiting) since Fri 2010-01-01 08:00:04 CST; 5 years 3 months ago May 01 11:08:00 systemd[1]: Timer elapsed on updateimage.timer May 01 11:08:00 systemd[1]: updateimage.timer changed waiting - running May 01 11:08:00 systemd[1]: updateimage.timer got notified about unit deactivation. May 01 11:08:00 systemd[1]: updateimage.timer: Realtime timer elapses at Sat 2015-05-02 02:00:00 CST. #systemctl status updateimage.service -l â— updateimage.service - Update image Loaded: loaded (/lib/systemd/system/updateimage.service; static) Active: inactive (dead) since Fri 2015-05-01 11:08:00 CST; 18min ago Process: 579 ExecStart=/bin/updateImage.sh (code=exited, status=0/SUCCESS) Main PID: 579 (code=exited, status=0/SUCCESS) May 01 11:08:00 systemd[1]: Enqueued job updateimage.service/start as 1019 May 01 11:08:00 systemd[1]: Forked /bin/updateImage.sh as 579 May 01 11:08:00 systemd[1]: updateimage.service changed dead - start May 01 11:08:00 systemd[579]: Executing: /bin/updateImage.sh May 01 11:08:00 systemd[1]: Child 579 belongs to updateimage.service -- laborish 2015-05-01 10:34 GMT+08:00 Cameron Norman camerontnor...@gmail.com: On Thu, Apr 30, 2015 at 6:35 PM, Likang Wang labor...@gmail.com wrote: Hi all, The entire system is running on an embedded box, and the system time will be set to 2008-01-01 00:00:00 after every reboot. My app running on the box will get the real time from my server and update time on the box after every booting.(I could not use NTP or systemd-timesyncd for some other reason) Does the service file for this custom time syncing service have the directive `Before=time-sync.target` ? If it does, are you sure that when it is considered running by systemd that the time has indeed been synced? Cheers, -- Cameron Norman ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
