I have an Ubuntu 14.04.4 LTS VM running under Vagrant and VirtualBox. When comparing its time to the server's I see things like this:
$ ntpdate -q ntp.ubuntu.com
server 91.189.94.4, stratum 2, offset -0.527602, delay 0.11812
server 91.189.89.198, stratum 2, offset -0.415140, delay 0.12631
server 91.189.89.199, stratum 2, offset -0.666563, delay 0.12758
server 91.189.91.157, stratum 2, offset -0.561897, delay 0.04617
3 Aug 20:40:38 ntpdate[17776]: step time server 91.189.91.157 offset -0.561897 sec
$ ntpdate -q ntp.ubuntu.com
server 91.189.91.157, stratum 2, offset 0.005067, delay 0.04915
server 91.189.94.4, stratum 2, offset -0.969532, delay 0.11708
server 91.189.89.198, stratum 2, offset -0.991536, delay 0.12196
server 91.189.89.199, stratum 2, offset -0.871215, delay 0.12868
3 Aug 20:42:21 ntpdate[17778]: step time server 91.189.94.4 offset -0.969532 sec
Note the huge difference in offset for the 2 invocations. 1/2 a second and almost 1 second.
I tried updating the time:
$ sudo ntpdate -s ntp.ubuntu.com
$ ntpdate -q ntp.ubuntu.com
server 91.189.91.157, stratum 2, offset -0.144275, delay 0.04559
server 91.189.94.4, stratum 2, offset -0.996168, delay 0.11856
server 91.189.89.198, stratum 2, offset -0.045262, delay 0.12607
server 91.189.89.199, stratum 2, offset -0.056879, delay 0.12617
3 Aug 20:44:16 ntpdate[17859]: adjust time server 91.189.89.198 offset -0.045262 sec
Which made the offset much less. But that's still a lot for having just been updated. On another server I saw an offset of .002.
What could be going on? This VM is configured identically, afaik, to other servers which do not have this problem. What should I check?