Linux Server time synchronization configuration

Time servers with CentOS7, other servers (Centos 6, RHEL7) Synchronize the server time

RHEL 7, CentOS 7 default network Time protocol is Chrony

This tutorial time Server service side host name: Centos7-node3 ip:192.168.231.130

Client 1 Host Name: Rhel7-node1

Client 2 host Name: Centos6-node2

Service side:

Check the status of the next Chrony service first

[Email protected] ~]# systemctl status Chronydunit Chronyd.service could not being found.

If the query does not have the service, you can install Yum

[[email protected] ~]# yum install -y chronyloaded plugins:  fastestmirrorbase                                                                                                                | 3.6 kB  00:00:00     extras                                                                                                              | 3.4 kB  00:00:00     updates                                                                                                             | 3.4 kB  00:00:00      loading mirror speeds from cached  Hostfile--------------------------------------------------------------omit part of the process--------------------------------------------- --------------------------running transaction  installing : chrony-3.2-2.el7.x86_64                                                                                                1/1   verifying  :  chrony-3.2-2.el7.x86_64                                                                                                1/1 Installed:  chrony.x86_64 0:3.2-2.el7                                                                                                                complete!

Start the Chrony service

[Email protected] ~]# systemctl start chronyd

Query status

[[Email protected] ~]# systemctl status chronyd  CHRONYD.SERVICE - NTP  client/server   Loaded: loaded  (/usr/lib/systemd/system/chronyd.service;  enabled; vendor preset: enabled)    Active: active  (running)  since  thu 2018-06-07 10:20:28 cst; 2s ago     docs: man : Chronyd (8)            man:chrony.conf (5)    process: 6031 execstartpost=/usr/libexec/chrony-helper update-daemon  (code=exited,  status=0/success)   Process: 6027 ExecStart=/usr/sbin/chronyd  $OPTIONS   (code= exited, status=0/success)  Main PID: 6029  (chronyd)    cgroup: / System.slice/chronyd.service           └─6029 /usr /sbin/chronydjun 07 10:20:28 centos7-node3 systemd[1]: starting ntp client/server ... jun 07 10:20:28 centos7-node3 chronyd[6029]: chronyd version 3.2  starting  (+cmdmon +ntp +refclock +rtc +privdrop +scfilter + ... DEBUG) jun 07 10:20:28 centos7-node3 chronyd[6029]: initial frequency - 29.914 ppmjun 07 10:20:28 centos7-node3 systemd[1]: started ntp client /server. jun 07 10:20:33 centos7-node3 chronyd[6029]: selected source  37.218.240.198jun 07 10:20:33 centos7-node3 chronyd[6029]: system clock  wrong by -3.020089 seconds, adjustment startedjun 07 10:20:30  centos7-node3 chronyd[6029]: system clock was stepped by -3.020089  Secondshint: some lines were ellipsized, uSe -l to show in full. 

Do the following configuration as a time server:

[[email protected] ~]# VIM/ETC/CHRONY.CONF25 # allow NTP Client access from local network.26 allow 192.168.231.0/2427 28 # Serve Time even if not synchronized to a time source.29 local stratum 10

Three server times, centos7-node3 for normal time

Client Configuration:

Client 1:

Delete or annotate the server 0.rhel.pool.ntp.org iburst---server 3.rhel.pool.ntp.org iburst

New \ Modify Configuration:

Server 192.168.231.130 Iburt

Allow 192.168.231.0/24

[[email protected] ~]# vim /etc/chrony.conf  1 # use public  servers from the pool.ntp.org project.    2 # please  consider joining the pool  (http://www.pool.ntp.org/join.html).     3   #server  0.rhel.pool.ntp.org iburst    4  #server  1. rhel.pool.ntp.org iburst    5  #server  2.rhel.pool.ntp.org iburst     6  #server  3.rhel.pool.ntp.org iburst    7 server  192.168.231.130 iburst    8 # ignore stratum in source  selection.    9 stratumweight 0   10     11 # record the rate at which the system clock gains/ Losses time.   12&nBsp;driftfile /var/lib/chrony/drift   13    14 # enable  kernel RTC synchronization.   15 rtcsync   16     17 # in first three updates step the system clock  instead of slew   18 # if the adjustment is  Larger than 10 seconds.   19 makestep 10 3   20     21 # Allow NTP client access from local  Network.   22 allow 192.168.231.0/24

After the modification is complete, save, restart the Chrony service to take effect

[Email protected] ~]# systemctl restart Chronyd

Client 2 Centos6-node2

CentOS 6 is NTP

Execute Ntpdate 192.168.231.130

[[email protected] ~]# ntpdate 192.168.231.130 7 June 16:59:34 ntpdate[1563]: The NTP socket is on use, exiting

If the above error occurs, stop the NTP service and then execute Ntpdate 192.168.231.130

[[Email protected] ~]# service ntpd stopshutting down ntpd: [OK][[email Protect Ed] ~]# ntpdate 192.168.231.130 7 June 17:00:19 ntpdate[1578]: Step time Server 192.168.231.130 offset-13589998.954539 sec [[Email protected] ~]# service ntpd statusntpd is stopped[[email protected] ~]# Datethu June 7 17:00:37 CST 2018

Then add time synchronization to the scheduled task

[Email protected] ~]# CRONTAB-E0-59/10 * * * */usr/sbin/ntpdate 192.168.231.130

10-minute synchronization

Now look at the next three server times are consistent

Linux Server time synchronization configuration