We just came off an Azure project and we thought it would be useful to push out our notes on keeping a hosted server time in sync.
1. We were configuring a Linux hosted server on Azure and thehe NTP protocol uses UDP on port 123. But you don’t have to allow that on ‘iptables’ in Linux – NTP just gets passed through.
2. On Azure you don’t have to define the port in the VM configuration, like you do for 22/80/443.
3. Old) posts say Azure doesn’t support UDP, but it seems to now.
4. In theory, Azure provides a service “time.windows.com” but it was 80ms behind the standard servers at .centos.pool.ntp.org.
After configuring the clock on the hosted Linux appliance starts drifting very quickly.
The problem seems to be that there are problems with the time sync in Hyper-V on Windows Server 2008, which is what Azure is built on.
The solution is to look at the changes required to grub.conf and ntp.conf as described at: