Time Zone, Server Clocks, VMWare, Virtual Machines.

Hey Team....

Here is the problem Occasionally say once a month or so, the Domain controller clocks, (and the all the Server Clients and Workstation CLients) adjust their system time by 3 hours (moves forward).

So if the server is in the eastern time zone, and this issue occurs, the clock will move forward by 3 hours. If its suppoed to be 8:00 PM Pacific, it will show 11:00 PM, for eastern the same thing.

The only way to fix the issue is to restart the windows time service on all domain controllers. The issue only seems to affect the VM Domain Controllers

This causes logins to the domain to intermittently fail, once the time service is restarted on all the domain controllers, then the tiume corrects itself and the (logon issue) goes away.

What I have checked so far:

1) All servers have the correct time zone set, for the timezone the server is physically in.
2) None of the servers (domain controllers) are syncing their time to the VMWare host
3)The NTP servers for each of the Windows Domains (there are many windows domain that this same issues occurs on) - are all correct and the time service is working.

Any ideas? on this? I really dont understand what is happening here. When the issue occurs every domain controller, regardless of timezone has its clocks moved forward by 3 hours.


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Seth SimmonsSr. Systems AdministratorCommented:
do the guests have vmware tools installed?
castellansolutionsAuthor Commented:
Yes all guests have VMWare tools installed
vmwarun - ArunCommented:
The way time sync should work is your Active Directory clients should sync with the Domain Controller which has the PDC Emulator FSMO role. The PDC emulator should sync with a trusted NTP source.

This article should be helpful in understanding how time sync works in VMware
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Paul SolovyovskySenior IT AdvisorCommented:
If the servers are virtual they'll first get their time from the ESXi hosts so make sure you have them pointed to a NTP source.  What happens with nodes that connect to a domain controller is that even when they finally pick up the correct time from the domain controller the system sees the time difference and may have problems logging in.

I would recommend setting your domain controllers (if physical) to NTP source and then the ESXi hosts to the same source.  This will ensure that all the hosts and nodes get the same time.
vmwarun - ArunCommented:
Offtopic - Good to see you answer, Paul.
castellansolutionsAuthor Commented:
well apparently esx07 was using the BIOS for its time source and not our time server. i dont know if thats really the iussue. BEucase were not talking about a time skew of a few minutes were talking about 3 hours off all of the sudden. with no reboots of any of the Virtaul machines.

So this case will need to stay open for a while.
castellansolutionsAuthor Commented:

I did review the link you provided but am still unclear, should i or should i not - have the windows domain controllers sync their clocks to the VM host clocks?

vmwarun - ArunCommented:
Never sync an AD domain controller's time to an ESXi host. The best way would be to sync with a dedicated NTP server in your environment or better sync the DC with the Internet time servers.

AD clients sync time with DC (PDC Emulator to be specific) -> PDC Emulator in-turn should sync time with an external NTP server such as servers listed on the URL, http://www.pool.ntp.org/en/

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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization ConsultantCommented:
We setup our TIME as follows:-

1. Sync ESXi Host time with Internal Tim Server (if you do not have one, Internet Time Source is acceptable).

2. Sync Domain Controller PDC emulator with same time source as 1.

3. ALL VMs (Windows) will time sync with domain e.g. 2 above.

4. Linux VMs we Time Sync with 1 above.

5. Disable VMware Tools Sync Time with Host!
castellansolutionsAuthor Commented:

Ok. So here is the deal. None of the domaain controllers were set to sync with the ESX Host, However as mentioned before one of the ESX Hosts didnt have the correct time, and also had no NTP setup. We fixed that and the time corrected itself on the ESX Host.

My question is if the DCs werent rebooted and since were not using any snapshots of the DCs themselves how did the time get set incorrectly on the DCs ?

You may not have enough info to answer that, and i do think we got the issue resolved, i just want to be sure its fixed.

But thanks becuase at least now we've made progress.
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization ConsultantCommented:
1. DCs synced with the Host

2. DCs syned with another time source which was incorrect.
castellansolutionsAuthor Commented:
Well so far no issues with this. I would like to keep this open a little longer in case the issue re-occurs (As it has done in the past).

vmwarun - ArunCommented:
Great. Please keep us updated and let us know in case you require more help.
castellansolutionsAuthor Commented:
This issue seems to be resolved!! Thanks for your help that VMWare server was killing the whole domain.
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