RedHat release 7.3 This is a development machine, so I do not know its installation history. It was noticed that it did not keep its time synced very well, although ntpd is running.My investigations revealed that ntp is working fine but there is another service running that is also updating the time - unfortunately that service is 12 minutes fast!For example, I disable ntpd and run ntpdate. The computers time is reset.#timedatectl status      Local time: Tue 2016-11-22 13:27:56 GMT  Universal time: Tue 2016-11-22 13:27:56 UTC        RTC time: Tue 2016-11-22 13:27:17       Time zone: Europe/London (GMT, +0000)     NTP enabled: noNTP synchronized: no RTC in local TZ: no      DST active: nobut within a couple of minutes the time goes back to being 12 minutes fast (compare with RTC)#timedatectl status      Local time: Tue 2016-11-22 13:41:09 GMT  Universal time: Tue 2016-11-22 13:41:09 UTC        RTC time: Tue 2016-11-22 13:28:49       Time zone: Europe/London (GMT, +0000)     NTP enabled: noNTP synchronized: no RTC in local TZ: no      DST active: noI found some relevant messages in /var/log/messages*Nov 22 14:26:00 development systemd: Time has been changed Nov 22 14:38:27 development systemd: Time has been changed*Nov 22 14:27:00 development systemd: Time has been changed Nov 22 14:39:27 development systemd: Time has been changed*Nov 22 14:27:00 development systemd: Time has been changed Nov 22 14:40:27 development systemd: Time has been changed*Nov 22 14:39:00 development systemd: Time has been changed Nov 22 14:42:27 development systemd: Time has been changedThe ones marked * are where I have done a date 11221426. You can see something somewhere resets the time back to being 12 minutes fast. Note the time is always 27 seconds so it seems to run once a minute, although this slowly drifts (currently running at 28 seconds!).I spent a long time disabling services but I have not been able to find the one that is forcing my machine to be 12 minutes in the future. ntpd is disabled, but I know that one syncs to the correct time. Please can anyone suggest any other time updating services that I could check to see if they are running.  Additional informationAs suggested in the answers, I looked at chronyd. It was not running on my machine, and even if I have it running it sets the machine to the right time, not 12 minutes fast.chronyd.service - NTP client/serverLoaded: loaded    (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled)Active: inactive (dead)
RedHat server updates its time every minute
rhel;ntp
I did not think to mention that the machine was running under VMware, which is where the problem was. VMware tools has the option of time syncing although they recommend that you use ntp instead.In my case, timesync was enabled and the virtual machine was 12 minutes fast. So whenever I corrected the time, vmware tools kicked in and reverted my change. Plus, 12 minutes is too much for ntpd to handle so ntpd gave up.For the record, to see if vmware time sync is running...#vmware-toolbox-cmd timesync statusEnabledYes, it was enabled. To disable....#sudo vmware-toolbox-cmd timesync disableDisabledNo more inaccurate updates! Note, I am not familiar with the VMware setup, so I am not sure if it will be re-enabled after a reboot. 