If you are using the current version of Cumulus Linux, the content on this page may not be up to date. The current version of the documentation is available here. If you are redirected to the main page of the user guide, then this page may have been renamed; please search for it there.

Setting the Date and Time

This section discusses how to set the time zone, and how to set the date and time on the software clock on the switch. To configure NTP, see Network Time Protocol - NTP. To configure PTP, see Precision Time Protocol - PTP.

Setting the time zone, and the date and time on the software clock requires root privileges; use sudo.

Set the Time Zone

You can use one of two methods to set the time zone on the switch:

  • Edit the /etc/timezone file.
  • Use the guided wizard.

Edit the /etc/timezone File

To see the current time zone, list the contents of /etc/timezone:

cumulus@switch:~$ cat /etc/timezone

Edit the file to add your desired time zone. You can see a list of valid time zones here.

Use the following command to apply the new time zone:

cumulus@switch:~$ sudo dpkg-reconfigure --frontend noninteractive tzdata

Use the following command to change /etc/localtime to reflect your current time zone. Use the same value as the previous step.

sudo ln -sf /usr/share/zoneinfo/US/Eastern /etc/localtime

Follow the Guided Wizard

To set the time zone using the guided wizard, run the following command:

cumulus@switch:~$ sudo dpkg-reconfigure tzdata

For more information, see the Debian System Administrator's Manual - Time.

Set the Date and Time

The switch contains a battery backed hardware clock that maintains the time while the switch powers off and between reboots. When the switch is running, the Cumulus Linux operating system maintains its own software clock.

During boot up, the switch copies the time from the hardware clock to the operating system software clock. The software clock takes care of all the timekeeping. During system shutdown, the switch copies the software clock back to the battery backed hardware clock.

You can set the date and time on the software clock with the date command. First, determine your current time zone:

cumulus@switch:~$ date +%Z

If you need to reconfigure the current time zone, refer to the instructions above.

To set the software clock according to the configured time zone:

cumulus@switch:~$ sudo date -s "Tue Jan 26 00:37:13 2021"

You can write the current value of the software clock to the hardware clock using the hwclock command:

cumulus@switch:~$ sudo hwclock -w

See man hwclock(8) for more information.