Question

Can't get clock to stay in sync using NTP

Posted March 31, 2017 2.5k views
CentOS System Tools Ubuntu 16.04

Hi all,

I’m having some serious issues getting the clock on my droplet to sync decently (I wanted to use my droplet to provide NTP service as part of the pool, but it’s annoying that I can’t provide decently accurate time). ntpd is synced to good time servers, and while initially the clock will be very good (getting down to 1ms or less offset), over time it gets out of sync to the tune of 20-50ms. I know NTP will keep the clock in sync better than this, and I’ve heard of people running NTP servers on DO droplets with much better results than I’m seeing. So it has to be something in my config, but damned if I know what.

Any ideas on what to try? I’m running one of the 512 MB droplets, currently using Ubuntu 16.04 (have also tried CentOS 7.3, with similar issues). Using a pretty standard ntpd config (I am installing/configuring it through Puppet using the puppetlabs module, all I am tweaking is to specify the upstream servers to sync to).

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1 answer
hansen March 31, 2017

@drzewiec

From what I remember about running NTP on a virtual environment, you shouldn’t expect the same precision as on hardware, since the clock is emulated.

Where is your server located and which pools do you sync with? The closer, the better.

Are you running multiple-master database/file systems? Or why do you need such precision? Just curious.

Does the ntpd.log give any hints why it isn’t adjusting?

And do you know the other people running, if they’re also running on 512MB droplet? Don’t see why that should be an issue, since the system should almost be idle, but still.
And can you ask them for their configuration, so you can match with yours?

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  • hansen March 31, 2017

    @drzewiec
    By the way, was looking around and found Chrony, which seems like a better candidate than NTPd:
    https://chrony.tuxfamily.org/comparison.html

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  • drzewiec April 4, 2017

    No idea about what others’ configuration is like, it’s just what I found from old posts on mailing lists and stuff. As for why I want precision, it’s really just a desire to provide the best service I can. I don’t want to be running a public NTP server if it sucks, after all. I’d use physical hardware if I could, but my ISP doesn’t give out static IP addresses so I can’t do that.

    I’m trying out chrony, will see if that helps things out. Will keep you posted if it does!

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