NTP时间服务器

一台虚拟机做中继，令一台虚拟机同步时间

1.先安装ntf

[root@mysqlb ~]# yum install chrony

[root@mysqlb ~]# systemctl start chronyd 

[root@mysqlb ~]# systemctl enable chronyd (开机自启)

[root@mysqlb ~]# vim /etc/chrony.conf

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org iburst
server 2.centos.pool.ntp.org iburst
server 3.centos.pool.ntp.org iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Enable kernel synchronization of the real-time clock (RTC).
rtcsync

# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *

# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2

# Allow NTP client access from local network.
#allow 192.168.0.0/16
allow 192.168.88.0/24　　在88网段
# Serve time even if not synchronized to a time source.
#local stratum 10

　用 chronyc sources查看

[root@mysqlb ~]# chronyc sources
210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^+ h199-182-204-197.ip4.unm>     2  10   377   765  +9769us[  +10ms] +/-  108ms
^* b9d1-55de.led01.ru.misak>     2  10   377   304  +6515us[+7153us] +/-   72ms
^- 195.148.70.254                2  10   375   35m  +6299us[  +11ms] +/-  212ms
^+ electrode.felixc.at           3  10   153   316  -1574us[ -937us] +/-  163ms

切换另一个虚拟机

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
server 192.168.88.101 iburst

# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift

# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3

# Enable kernel synchronization of the real-time clock (RTC).
rtcsync

# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *

# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2

# Allow NTP client access from local network.
#allow 192.168.0.0/16

　　

[root@slave1 ~]# chronyc sources
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^* localhost                     3   6   377    56   -211us[  -21us] +/-   73ms