NTP Time Synchronization: Linux Server Clock Configuration

Linux server time synchronization is a fundamental and critical task. The Network Time Protocol (NTP) is the core tool that addresses issues such as log chaos, service authentication failures, and data conflicts. NTP achieves time synchronization through a hierarchical structure (Stratum 1-16, where lower strata are more authoritative). Common tools include NTPD (classic but resource-intensive) and Chrony (lightweight, fast to start, suitable for servers with limited memory). Taking NTPD as an example for installation: For CentOS/RHEL (below 7.9), use `yum install ntp -y`. For Ubuntu/Debian, use `apt install ntp -y` (Note: CentOS 7+ requires uninstalling Chrony first). Configure `/etc/ntp.conf` by adding authoritative servers (e.g., `ntp.aliyun.com`), and open the UDP 123 port in the firewall. Start the service with `systemctl start ntpd && enable`. Verify synchronization status using `ntpq -p`, and perform manual synchronization with `ntpdate -u`. Chrony follows a similar basic configuration and startup process; verification is done via `chronyc sources`. Common issues like service startup failures or slow synchronization can be resolved by checking ports, network connectivity, or replacing servers. Time synchronization is essential for server