How can I resolve the drifting clock for my Virtual Machine?
My Virtual Machine's clock drifts pretty significantly. There's documentation out there about dealing with this, but nothing seems to be working very well.
Anyone have any suggestions, things that worked well for them, ...
Supposedly updating regularly via ntp is not a good solution.
Answer
- Read you vmware documentation carefully before you listen to anyone. We are running ESX5.
Timekeeping best practices for Linux guests among other things says: Ref: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427
NTP Recommendations Note: VMware recommends you to use NTP instead of VMware Tools periodic time synchronization. NTP is an industry standard and ensures accurate time keeping in your guest. You may have to open the firewall (UDP 123) to allow NTP traffic.
This is a sample /etc/ntp.conf:
tinker panic 0
restrict 127.0.0.1
restrict default kod nomodify notrap
server 0.vmware.pool.ntp.org
server 1.vmware.pool.ntp.org
server 2.vmware.pool.ntp.org
driftfile /var/lib/ntp/drift
This is a sample (RedHat specific) /etc/ntp/step-tickers:
0.vmware.pool.ntp.org
1.vmware.pool.ntp.org
The configuration directive tinker panic 0 instructs NTP not to give up if it sees a large jump in time. This is important for coping with large time drifts and also resuming virtual machines from their suspended state.
Note: The directive tinker panic 0 must be at the top of the ntp.conf file.
It is also important not to use the local clock as a time source, often referred to as the Undisciplined Local Clock. NTP has a tendency to fall back to this in preference to the remote servers when there is a large amount of time drift.
An example of such a configuration is:
server 127.127.1.0
fudge 127.127.1.0 stratum 10
Comment out both lines.
After making changes to NTP configuration, the NTP daemon must be restarted. Refer to your operating system vendor’s documentation.