System time change - VM Sycning with Host HW Time

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asifrajan
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Joined: 2010/05/20 11:59:24

System time change - VM Sycning with Host HW Time

Post by asifrajan » 2023/06/02 00:32:20

Host HW: HPE DL 380 Gen 10
Hypervisor: VMWare ESXi
VM: Centos 7.9
NTP Service: Chrony

We started observing "Time has been changed" messages in /var/log/messages. System clock was advancing by 480 seconds. Then Chronyd was pulling the time back and correction was made. This was happening while VM was running.

In VMWare setting we have already checked not to sync time with HW. The VM has been in the environment for more than a year but we started to see this phenomena from May 24th onwards.

Upon looking further we found out that the Host HW clock was roughly 7 minutes fast and the VM was syncing time with that. We have set the HW clock to correct time now but why would an operational VM sync time with its HW Host when NTP is already configured?

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TrevorH
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Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: System time change - VM Sycning with Host HW Time

Post by TrevorH » 2023/06/02 12:27:39

It'll only sync with the host if you've told it to. Has the machine been "power cycled" since the VMWare setting was set?
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

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