Setting Date and Time
Setting the time zone, date and time requires root privileges; use
Setting the Time Zone
To see the current time zone, list the contents of
cumulus@switch:~$ cat /etc/timezone US/Eastern
Edit the file to add your desired time zone. A list of valid time zones can be found at the following link.
Use the following command to apply the new time zone immediately.
dpkg-reconfigure --frontend noninteractive tzdata
Alternative: Use the Guided Wizard to Find and Apply a Time Zone
To set the time zone, run
dpkg-reconfigure tzdata as root:
cumulus@switch:~$ sudo dpkg-reconfigure tzdata
Then navigate the menus to enable the time zone you want. The following example selects the US/Pacific time zone:
cumulus@switch:~$ sudo dpkg-reconfigure tzdata Configuring tzdata ------------------ Please select the geographic area in which you live. Subsequent configuration questions will narrow this down by presenting a list of cities, representing the time zones in which they are located. 1. Africa 4. Australia 7. Atlantic 10. Pacific 13. Etc 2. America 5. Arctic 8. Europe 11. SystemV 3. Antarctica 6. Asia 9. Indian 12. US Geographic area: 12 Please select the city or region corresponding to your time zone. 1. Alaska 4. Central 7. Indiana-Starke 10. Pacific 2. Aleutian 5. Eastern 8. Michigan 11. Pacific-New 3. Arizona 6. Hawaii 9. Mountain 12. Samoa Time zone: 10 Current default time zone: 'US/Pacific' Local time is now: Mon Jun 17 09:27:45 PDT 2013. Universal Time is now: Mon Jun 17 16:27:45 UTC 2013.
For more info see the Debian System Administrator’s Manual - Time.
Setting the Date and Time
The switch contains a battery backed hardware clock that maintains the time while the switch is powered off and in between reboots. When the switch is running, the Cumulus Linux operating system maintains its own software clock.
During boot up, the time from the hardware clock is copied into the operating system’s software clock. The software clock is then used for all timekeeping responsibilities. During system shutdown the software clock is copied back to the battery backed hardware clock.
You can set the date and time on the software clock using the
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.
Then, to set the system clock according to the time zone configured:
cumulus@switch$ sudo date -s "Tue Jan 12 00:37:13 2016"
man date(1) for if you need more information.
You can write the current value of the system (software) clock to the
hardware clock using the
cumulus@switch$ sudo hwclock -w
man hwclock(8) if you need more information.
Setting Time Using NTP
ntpd daemon running on the switch implements the NTP protocol. It
synchronizes the system time with time servers listed in
/etc/ntp.conf. It is started at boot by default. See
man ntpd(8) for
/etc/ntp.conf contains some default time servers. Edit
/etc/ntp.conf to add or update time server information. See
man ntp.conf(5) for details on configuring
To set the initial date and time via NTP before starting the
ntpd -q (This is same as
ntpdate, which is to be retired
and not available).
ntpd -q can hang if the time servers are not reachable.
To verify that
ntpd is running on the system:
cumulus@switch:~$ ps -ef | grep ntp ntp 4074 1 0 Jun20 ? 00:00:33 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -u 101:102
To check the NTP peer status:
cumulus@switch:~$ ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== *level1f.cs.unc. .PPS. 1 u 225 1024 377 92.505 -1.296 1.139 +ip.tcp.lv 184.108.40.206 2 u 29 1024 377 192.701 2.424 1.227 -host-220.127.116.11 18.104.22.168 2 u 1024 1024 367 240.622 11.250 7.785 +li290-38.member 22.214.171.124 2 u 553 1024 377 38.944 -0.810 1.139
Specifying the NTP Source Interface
You can change the source interface that NTP uses if you want to use
something other than the default of eth0. Edit
ntp.conf and edit the
entry under the # Specify interfaces comment:
# Specify interfaces interface listen bridge10
ntpd init.dconfiguration variables
/etc/ntp.conf - default NTP configuration file