I've installed the OS and the time is incorrect.
The timedatectl shows:
System clock synchronized: no
systemd-timesyncd.service active: yes
RTC in local TZ: no
How to force it to sync now?
From man timedatectl, NTP-sync needs to be enabled:
sudo timedatectl set-ntp true
Then timedatectl should do the rest automatically (see Redbob's reply).
If timedatectl does not show "System clock synchronized: yes", check the status of systemd-timesyncd:
systemctl status systemd-timesyncd
and restart it:
sudo systemctl restart systemd-timesyncd
Check the status of timedatectl again:
$ timedatectl
...
System clock synchronized: yes
systemd-timesyncd.service active: yes
RTC in local TZ: no
It worked for me, when I edited /etc/systemd/timesyncd.conf, because lines below were commented.
I uncommented them and changed NTP and FallbackNTP lines by my Network servers:
[Time]
NTP=172.24.3.1
FallbackNTP=172.24.44.51
RootDistanceMaxSec=5
PollIntervalMinSec=32
PollIntervalMaxSec=2048
After that, I restarted systemd-timesyncd.service, so System clock synchronized status turned to yes
System clock synchronization depends on a number of factors:
/etc/systemd/timesyncd.conf must be properly configured/etc/systemd/timesyncd.conf or changes to the masking)To enable timedatectl NTP-sync:
$ sudo timedatectl set-ntp true
I have seen /etc/systemd/timesyncd.conf differ on different installs of Ubuntu. On some installs, the [Time] section of /etc/systemd/timesyncd.conf is commented out.
NTP and RootDistanceMaxSec in /etc/systemd/timesyncd.confRootDistanceMaxSec may need to be increased (e.g. 30, see this StackExchange post)/etc/systemd/timesyncd.conf:
...
[Time]
NTP=192.168.1.1
FallbackNTP=ntp.ubuntu.com
RootDistanceMaxSec=30
PollIntervalMinSec=32
PollIntervalMaxSec=2048
Unmask systemd-timesyncd:
sudo systemctl unmask systemd-timesyncd
Restart systemd-timesyncd after changes and check its status:
sudo systemctl restart systemd-timesyncd
systemctl status systemd-timesyncd
systemd-timesyncd should be enabled and active (running):
● systemd-timesyncd.service - Network Time Synchronization
Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset: enabled)
Active: active (running) since Sat 2024-08-31 14:52:32 EDT; 1 months 14 days ago
...
Now timedatectl should show the system clock is synchronized:
$ timedatectl
Local time: Tue 2024-10-15 05:19:07 EDT
Universal time: Tue 2024-10-15 09:19:07 UTC
RTC time: Tue 2024-10-15 09:19:06
Time zone: America/Kentucky/Monticello (EDT, -0400)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no