Manually Setting the System Clock

Product support
16

This did not seem to work. I must admit it took a little bit to get it to function because I fell into this pitfall:

This is the reply from the dbus-send command:

17.04.20 09:58:00 (+0000)  api  method return time=1587117480.786902 sender=:1.1 -> destination=:1.6250 serial=177495 reply_serial=2
17.04.20 09:58:00 (+0000)  api     object path "/org/freedesktop/systemd1/job/79940"

When I changed the system time on the device, disconnected from the network, and power cycled it came up with a completely incorrect time. I thought originally that I would have to change the rtcsync directive in chrony to rtcfile, which is why I had originally asked how to edit that configuration:

The hwclock program is often set-up by default in the boot and shutdown scripts with many Linux installations. With the kernel RTC synchronisation ( rtcsync directive), the RTC will be set also every 11 minutes as long as the system clock is synchronised. If you want to use chronyd 's RTC monitoring ( rtcfile directive), it’s important to disable hwclock in the shutdown procedure. If you don’t, it will over-write the RTC with a new value, unknown to chronyd . At the next reboot, chronyd started with the -s option will compensate this (wrong) time with its estimate of how far the RTC has drifted whilst the power was off, giving a meaningless initial system time.

There is no need to remove hwclock from the boot process, as long as chronyd is started after it has run.

chrony – Frequently Asked Questions

After reconnecting to the network, and then power cycling again it’s clear that NTP was used because the system time now reflects the current UTC time.