Keeping Ubuntu server clock in sync
Yesterday we ran into a problem with a server running Ubuntu with a clock that was not set correctly. It was one minute and 17 seconds wrong. This may or may not be much depending on your application, but I needed a way to sync it continously.
Wait, doesn’t the system handle this by itself?
Yes and no. Every reboot the clock syncs. But as you know, servers can (and should) be running for months without rebooting.
The simple solution
Just run sudo apt-get install ntp and give it a couple of minutes. It will
automatically sync with the nearest NTP server.
The bad thing with this is that it adds a small extra load on your server, but
won’t be noticable for most people.
Your time will be correct with an error margin of a few milliseconds.
The ‘one sync per day’ option
For most people the above solutions is perfecly fine, but if you only need the time to be approximately correct (within a few seconds) you can use the following method
- Create a file named
/etc/cron.daily/timesyncwith the following contents:ntpdate ntp.ubuntu.com - Make sure the file is executable with
sudo chmod 755 /etc/cron.daily/timesync
Now your time will be more correct than most people’s wrist watches.