Windows Instance cannot keep time correctly.

Question

Hello,  
  
I have an application that is timing critical, but for some reason, the Windows Server (t3.small) that I started, is having trouble keeping basic time.  
  
I have synced the OS with internet time multiple times. Immediately after syncing, the time (accurate to the seconds) would be correct. But later on in the day, when I check back, it would always be off again. Most of the time, being 3 to 5 seconds faster than the actual present time (There was one instance it was actually slower by around 3 seconds, but most of the time, it would be faster).  
  
I have re-synced with internet time multiple times now, and it has not solved the problem. I have scheduled tasks that are timing critical, and must resolve this issue.  
  
Thank you.

Accepted Answer

AWS recommend that configure your instance to use the Amazon Time Sync Service also according to article,Windows AMIs use the Amazon Time Sync Service by default since 2018.

Answer

It has been 2 days since I implemented Amazon Time Sync, and so far, the system is keeping much better time. However, occasionally it would still appear to be off by 1 second, but it this is a major improvement over what it was (3 to 5 seconds).  
  
All new AMIs should already use Amazon Time Sync by default, but my instance was built from a saved image I had from 2 years ago, this is probably the reason why my system does not have it set as default.  
  
I will observe the system for an additional couple of days, and if things stay within parameters, I will mark your response as the correct answer.  
  
Thank you.

Answer

I will look into it, but why is this necessary? Is there something that is preventing it from keeping proper time?  
  
Would this help the system time being kept accurate? Because the scheduled tasks are triggered by window's internal scheduler, which is based on system time.

Answer

You can use Amazon Time Sync Service. Natively accessible from all ec2 instances.  
  
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/windows-set-time.html

Windows Instance cannot keep time correctly.

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