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  • 1.  NTP on ESXi 8 doesn't work

    Posted Jan 30, 2024 03:10 PM

    Hi guys,

    I have vsphere cluster on version 8. This is a new implementation.

    On this cluster I made VM with NTP server on Ubuntu server OS. NTP is working and have correct time.

    I set NTP on ESXi for this server, but synchronisation between ESXi and NTP server doesn't work. The FW rules on the NTP server are open.

    What else can I check to solve this problem? On an ESXi, I add the server x.x.x.x value "version 3" in the /etc/ntp.conf file, but this doesn't solve the problem.

    Communication between ESXi and Ubuntu is fine. Ping resolves and ESXi has access via UDP port 123.



  • 2.  RE: NTP on ESXi 8 doesn't work

    Posted Jan 30, 2024 04:27 PM

    Hi,

     

    check the following article which might offer steps you didn't check till now.

    Troubleshooting NTP on ESX and ESXi 6.x / 7.x / 8.x



  • 3.  RE: NTP on ESXi 8 doesn't work

    Posted Jan 31, 2024 11:13 AM

    Hi,

    I've checked it before and it doesn't help me.



  • 4.  RE: NTP on ESXi 8 doesn't work

    Posted Feb 01, 2024 07:24 AM

    Hi,

     

    may I ask if you're using a w32tm driven NTP server (like AD Controller)?

    I did run into similar problems several months ago and when I remember correctly using the following command to configure w32tm did solve the problems.

    w32tm /config /manualpeerlist:"<0.de.pool.ntp.org>,0x8 <1.de.pool.ntp.org>,0x8 <2.de.pool.ntp.org>,0x8 <3.de.pool.ntp.org>,0x8" /syncfromflags:manual /update

    Please adjust the command to refer to your preferred time servers.



  • 5.  RE: NTP on ESXi 8 doesn't work

    Posted Jan 31, 2024 10:03 PM

    Probably doesn't, but I wonder if vSphere does something 'clever' and prevents ESXi NTP settings from using a VM based time source inside the hosting environment.

    Its the sort of thing I would do, because of the way the VM boot up sequence works.

    When a VM starts up, because it doesn't have a proper BIOS and battery backed CMOS realtime clock like a real PC, the virtual BIOS system time is set by synchronising with the host as it boots.

    If the VM is then to provide the host with time, I can see an odd circular loop existing here, which doesn't seem like a good thing to me.

      



  • 6.  RE: NTP on ESXi 8 doesn't work

    Posted Feb 04, 2024 08:05 PM

    Apologies for going back to basics, but is the ntpd service running on your ESXi host? Also ensure the policy for the ntpd service is set to start and stop with the host.

    Also does NTP work fine if you point to an Internet Time server? If so, then it could be a problem with the configuration on your NTP VM. Can anything else on your network use it successfully as a time source?