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Using Ubuntu 12.04 VM's built last year on Azure. They only seem to get proper time on boot, and drift about a second a day. Is this a normal issue for Azure VM's? I know VM time drift is normal but thought Linux VM's in Azure (Hyper-V) get regular time sync from the host via integration services.

  • The whole "Large clock drift with Linux Hyper-V guests" is a well discussed issue (but strangely little concrete information other than use ntpd/chrony). See serverfault.com/q/523389 for details. – Anon Mar 27 '14 at 15:15
  • Does this problem still occur as of today? – Igor Gatis Apr 8 '18 at 21:05
  • That question was 4 years ago, I have no idea now. – Bret Fisher Apr 9 '18 at 16:28
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The OS usually only reads the (emulated) hardware clock upon boot, and then the clock is maintained with an interrupt timer. This is not a perfect time source, of course, and therefore you have to use NTP software to keep it accurate.

  • The question isn't that a VM may drift, but rather why is Azure time sync not keeping these VM's in check. – Bret Fisher Feb 4 '14 at 21:27
  • Are you sure that is supposed to happen? AFAIK, the VM is on it's own when it comes to the clock. – Halfgaar Feb 5 '14 at 8:09
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Seems others have this issue, even in Windows VM Roles. Once a week is causing too much time drift so I guess manual setting daily or less is indeed in order:

https://stackoverflow.com/questions/6186776/how-to-validate-local-vm-clock-with-ntp-on-windows-azure

  • VM Roles are not supported anymore (and haven't been for a long time), and that particular SO post is over 2 years old. – David Makogon Feb 8 '14 at 5:02
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This is expected because Hyper-V's clock sync does not necessarily continue to discipline the clock after boot up - see one of the answers on Timesync on HyperV with CentOS 6.2 for details.

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Time drift is normal for all computers. You have to use ntpd to keep your time accurate.

  • sorry, you're just repeating what I've said in my question "VM time drift is normal but thought Linux VM's in Azure (Hyper-V) get regular time sync..." – Bret Fisher Feb 4 '14 at 21:27

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