Guide: Keeping time in vmware ESX

A challenge I ran into last time is to keep the correct time in vmware esx and the virtual machines.

You can setup the vmware ESX server to use NTP servers (Network Time Protocol) to synchronize the time on the ESX servers and using vmware tools to sync the vm's time with the ESX server. I found the following articles on the vmware website related to keeping time

Steps

1 Make sure your ESX servers are setup with the correct timezone settings

If you made a mistake during installation (or moved your physical server into a new timezone) here is the procedure on how to fix it

Timezone: http://kb.vmware.com/selfservice/viewContent.do?externalId=1436

2 Setup the "Network Time Protocol" on vmware ESX

Then you can move on to configuring your NTP servers

NTP protocol: http://kb.vmware.com/selfservice/viewContent.do?externalId=1339

3 Disable the "Windows Time Service" in your microsoft Windows VM's

Now that we have setup ESX to get the correct time we can disable the time service in windows and let vmtools take care of the time synchronization. In the following article is described why this is a good idea and more important how to do it

Windows Time Service: http://kb.vmware.com/selfservice/viewContent.do?externalId=1318

For a deeper technical description of how time in ESX and the virtual machines work together please have a look at this PDF document LINK

Conlusion

Time keeping in vmware ESX is a bit of a configuration, but if your applications running in the VM's depend on correct time settings its important that the time is correct

I hope that vmware in future releases puts the time management options in the vmware client (or virtual center) to make it easier to manage

Stefan Schuller

me(-at-)stefanschuller.com

Last edited: 24th of may 2007