解决Linux时间同步问题：双机同步教程（两台linux时间同步）

It is essential to keep the time in sync on all Linux systems. An incorrect clock time can lead to problems such as inaccurate log files or errors when executing tasks. In this tutorial, we will discuss two methods for syncing Linux server time across multiple systems.

The first way to achieve accurate time synchronization on Linux systems is to use the Network Time Protocol (NTP). NTP is an extremely accurate protocol which is specifically designed to ensure that clocks on machines are synchronized over the network. We can use the following commands to install and configure NTP on an Ubuntu or CentOS based machine:

Ubuntu：

“`shell

sudo apt-get install ntp

sudo ntpdate [NTP server]

sudo hwclock -w

CentOS:
```shell
yum -y install ntp
ntpdate [NTP server]
hwclock --systohc

Once NTP is installed and configured, we can monitor the NTP synchronization process using the command ‘ntpq –p’. Output from this command should resemble that below where each column of output represents a NTP server.

The second way to keep time in sync is to install a tool called rdate. This tool reads the time from a remote machine and sets the time of the local machine to the same value. To install rdate on Ubuntu, you can use the following command:

“`shell

sudo apt-get install rdate

Once installed, we can run the ‘rdate’ command with the ‘-s’ option, to set the system time to the same time as the remote machine. The ‘-s’ option requires a valid and accessible hostname, IP address or domain name that is running an NTP service.

In summary, in this tutorial we discussed two ways of keeping time in sync across multiple Linux systems. We firstly looked at using the Network Time Protocol, which allows us to keep clocks in sync in an accurate and reliable manner. We then discussed the installation and usage of the rdate tool. Using either of these methods should ensure time synchronization across Linux systems.