Configure systemd-timesyncd for Accurate NTP Sync on Linux

Original article: https://note.qidong.name/2020/09/install-powerline/ Author: 零壹軒

Background

Ubuntu uses ntp.ubuntu.com as its default time‑sync server and Debian uses servers such as 0.debian.pool.ntp.org. Accessing these from China often incurs high latency, though the impact on clock synchronization is usually minor.

Why configure manually?

In isolated environments—such as corporate intranets or cloud subnets without internet access—you cannot reach the public NTP servers, so you must set up your own synchronization source.

Installation

Most systems already have systemd-timesyncd installed. If it is missing, install it with: sudo apt install systemd-timesyncd Note that systemd-timesyncd conflicts with the traditional ntp daemon; only one can be installed at a time.

Configuration

Edit /etc/systemd/timesyncd.conf and set the NTP lines to servers reachable from China, for example:

[Time]
NTP=ntp7.aliyun.com
NTP=ntp6.aliyun.com

After saving the file, restart the service for the changes to take effect:

sudo systemctl restart systemd-timesyncd.service

If the service file is missing, recreate it with:

sudo dpkg-reconfigure systemd-timesyncd

Verify the configuration

Use timedatectl status to view detailed synchronization information. Example output:

$ timedatectl status
               Local time: Tue 2020-09-22 20:06:05 CST
           Universal time: Tue 2020-09-22 12:06:05 UTC
                 RTC time: Tue 2020-09-22 12:06:05
                Time zone: Asia/Shanghai (CST, +0800)
        System clock synchronized: yes
                  NTP service: active
          RTC in local TZ: no

Chinese NTP server list

Alibaba Cloud provides several NTP servers that can be pinged to choose the fastest one:

ntp1.aliyun.com
ntp2.aliyun.com
ntp3.aliyun.com
ntp4.aliyun.com
ntp5.aliyun.com
ntp6.aliyun.com
ntp7.aliyun.com