The Built-In Time Client
In modern Ubuntu releases (and most systemd-based Linux distributions), the operating system handles time synchronization via a built-in SNTP client called systemd-timesyncd. For standard desktops, laptops, and basic web servers, this lightweight service is perfect; it occasionally polls an external server and smoothly adjusts the local clock to prevent drift.
However, systemd-timesyncd is a simplified client, not a full NTP implementation. It cannot act as a time server for other machines on your local network, and it lacks the advanced hardware timestamping features required for high-frequency trading platforms or massive database clusters. If you are building a server that requires extreme precision and need to install the full, legacy ntp daemon (or modern alternatives like chrony), you must first completely disable the built-in systemd time service to prevent them from fighting over the system clock.
How to Disable the Systemd-Timesyncd Service
You can stop and disable the built-in time synchronization via the terminal.
- Open your Ubuntu Terminal or connect via SSH.
- Stop the currently running service immediately:
sudo systemctl stop systemd-timesyncd.service- Disable the service to prevent it from starting on the next boot:
sudo systemctl disable systemd-timesyncd.service- (Optional) To ensure no other systemd process attempts to revive it, mask the service:
sudo systemctl mask systemd-timesyncd.serviceYour Ubuntu system is now running without any active network time synchronization. You can now safely proceed to install and configure ntp or chrony to take over the clock management duties.