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45. Date and Time

SolarNodeOS includes date and time management functions through the timedatectl command. Run timedatectl status to view information about the current date and time settings.

Viewing the current date and time settings
$ timedatectl status
               Local time: Fri 2023-05-26 03:41:42 BST
           Universal time: Fri 2023-05-26 02:41:42 UTC
                 RTC time: n/a
                Time zone: Europe/London (BST, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

45.1 Changing the local time zone

SolarNodeOS uses the UTC time zone by default. If you would like to change this, use the dpkg-reconfigure tzdata

Changing the local time zone
$ sudo dpkg-reconfigure tzdata

This will present a menu to choose the desired time zone. You can also list the available time zone names by running timedatectl list-timezones.

Why not timedatectl set-timezone?

There are two time zone configuration files, /etc/localtime and /etc/timezone. These must be kept in sync, which dpkg-reconfigure tzdata will do but timedatectl set-timezone will not.

45.2 Internet time synchronization

SolarNodeOS uses the systemd-timesyncd service to synchronize the node's clock with internet time servers. Normally no configuration is necessary. You can check the status of the network time synchronization with timedatectl like:

$ timedatectl status
               Local time: Fri 2023-05-26 03:41:42 BST
           Universal time: Fri 2023-05-26 02:41:42 UTC
                 RTC time: n/a
                Time zone: Europe/London (BST, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Warning

For internet time synchronization to work, SolarNode needs to access Network Time Protocol (NTP) servers, using UDP over port 123.

45.2.1 Network time server configuration

The NTP servers that SolarNodeOS uses are configured in the /etc/systemd/timesyncd.conf file. The default configuration uses a pool of Debian servers, which should be suitable for most nodes. If you would like to change the configuration, edit the timesyncd.conf file and change the NTP= line, for example

Configuring the NTP servers to use
[Time]
NTP=my.ntp.example.com

45.3 Setting the date and time

In order to manually set the date and time, NTP time synchronization must be disabled with timedatectl set-ntp false. Then you can run timedatectl set-time to set the date:

Manually changing the date and time
$ sudo timedatectl set-ntp false
$ sudo timedatectl set-time "2023-05-26 17:30:00"

If you then look at the timedatectl status you will see that NTP has been disabled:

Status with NTP disabled
$ timedatectl
               Local time: Fri 2023-05-26 17:30:30 NZST
           Universal time: Fri 2023-05-26 05:30:30 UTC
                 RTC time: n/a
                Time zone: Pacific/Auckland (NZST, +1200)
System clock synchronized: no # (1)!
              NTP service: inactive # (2)!
          RTC in local TZ: no
  1. The clock is not synchronized with internet time servers, as it shows no
  2. The NTP service has been disabled, as it is listed as inactive

You can re-enable NTP time synchronization like this:

Enabling NTP time synchronization
$ sudo timedatectl set-ntp true