NTP offset issue

[#1]

Hello,

I have a GRID with 4 VM, IB-VM-810 running 8.2.1 version. The issue happens onece a month and it vary the offset from 0,X ms to a 0,X s:

Normal values:

Infoblox > show ntp

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

127.127.1.1     .LOCL.          14 l   5d   64    0    0.000    0.000   0.000

+150.214.94.5    .ROA.            1 u  184  256  377   37.491   -4.885   0.722

-150.214.94.10   .ROA.            1 u  173  256  367   36.894   -4.717   1.308

*130.206.3.166   .GPS.            1 u  251  256  377    2.961    0.491   0.257

+130.206.0.1     .GPS.            1 u  214  256   73    2.541    0.554   0.241

Four houers later:

Infoblox > show ntp

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

127.127.1.1     .LOCL.          14 l  24h   64    0    0.000    0.000   0.000

+150.214.94.5    .ROA.            1 u  110  256  373   37.699  512.162  63.914

+150.214.94.10   .ROA.            1 u  201  256  277   37.742  445.908  37.951

*130.206.3.166   .GPS.            1 u  247  256  377    2.940  490.243  24.921

-130.206.0.1     .GPS.            1 u  194  256  377    2.830  556.954 103.450

We did not see any problems at the network. What can produce this variation in the offset when it seems to work properly? has the versión any bugs? Could the problem be at the VM?

Thank´s!

[#2]

For a definitive answer on this I would suggest you open a support case. You can grab a supportbundle from the node where this happens and check the ntp logs and ntp stats file which will be in there. 

Based on the output you provided it looks like 150.214.94.10 and 130.206.0.1 are not as reliable (going by the reachability metric) If possible add a 5th timesource as that will allow ntp to detect if 2 other sources are unreliable. 

[#3]

Hellow,

Thank´s a lot for your answer Ingmar. Case is already opened. We will add that 5th timesource.

Regards.