How to deal with the amazon ec2's clock drift?

amazon-ec2 amazon clock drift
user2028644 picture user2028644 · Jan 31, 2013 · Viewed 10.8k times · Source

We have a couple of ec2 instances on amazon, and we used amazon AIM Linux to set up. The instance type is m1.medium.

Everything is going well until this week.

We found from log file that there would be a huge clock drift happened suddenly, and sometimes there has a 5-minutes discrepancy。

I would like to ask if anyone else encounter this problem? How to deal with it?

Answer

Ciaran picture Ciaran · Feb 3, 2014

Time drift can occur due to over utilization of your instances resources. I would encourage you to check you cloudwatch CPU graphs to try identify if your CPU was being over utilized.

If you are running amazon linux AMI, NTP is installed by default.

To verify if NTP is running run

sudo service ntpd status

If it is not installed you can run the following to install it:

sudo yum install ntp

If NTPD is running and your clock time is off I would try to restart it and see if it synchs with the NTP servers your have setup. You can also add more NTP servers by editing the /etc/ntp.conf file. Just search for NTP servers to find ones to add.

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