CentOS7系统上配置NTP时钟服务器

CentOS7系统上配置NTP时钟服务器


1、需要配置的计算机IP
192.168.195.10 ceph-node1
192.168.195.12 ceph-node2


设置IP=192.168.195.10为时钟服务器
IP=192.168.195.12服务器为需要同步机器


2、查看两个机器桑是否安装了ntp包


[root@ceph-node2 ~]# rpm -qa | grep ntp
fontpackages-filesystem-1.44-8.el7.noarch
python-ntplib-0.3.2-1.el7.noarch
ntpdate-4.2.6p5-22.el7.centos.x86_64
ntp-4.2.6p5-22.el7.centos.x86_64
这样的输出证明已经安装好了，其中包就是"ntp-4.2.6p5-22.el7.centos.x86_64"


3、配置ntp.conf文件
配置NTP服务器的关键是需要配置这个文件
[root@ceph-node2 ~]# vi /etc/ntp.conf


# For more information about this file, see the man pages
# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).


driftfile /var/lib/ntp/drift


# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default nomodify notrap nopeer noquery


# Permit all access over the loopback interface.  This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict ::1


# Hosts on local network are less restricted.
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap


# 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


#restrict 192.168.195.0 mask 255.255.0.0 nomodify
server 127.127.1.0
fudge 127.127.1.0 stratum 11


下面的省略了....

这是要改变的地方，server 0-3 注释掉，
加入本地时间服务器，主要是 127.127.1.0，由于是顶层服务，也就是说没有上级时间服务器
了，这里就是使用192.168.195.10的时间为准。
接着，重启或者启动ntpd服务：
[root@ceph-node1 ~]# systemctl restart ntpd.service
此时，ntpd服务器已经配置好了。再执行：
[root@ceph-node1 ~]# systemctl enable ntpd.service
使服务在系统启动后就开启。


4、在客户端机器上进行配置
[root@ceph-node2 ~]# vi /etc/ntp.conf

# For more information about this file, see the man pages
# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).

driftfile /var/lib/ntp/drift

# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default nomodify notrap nopeer noquery


# Permit all access over the loopback interface.  This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict ::1

# Hosts on local network are less restricted.
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

# 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 127.127.1.0  iburst     local  clock
#fudge 127.127.1.0 stratum 11
#restrict 192.168.195.0 mask 255.255.0.0 nomodify
server 192.168.195.10
fudge 127.127.1.0 stratum 11

下面省略....

主要是添加下面两行：
server 192.168.195.10
fudge 127.127.1.0 stratum 11#这个是需要11，因为不是顶级的


配置好保存，即可。
查看ntp服务状态：
[root@ceph-node2 ~]# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*ceph-node1      LOCAL(0)        11 u   32   64  377    0.168    0.003   0.139

refid为LOCAL(0)为准确。

5、测试

[root@ceph-node2 ~]# date -s "2017-02-14 19:00:00"
而ceph-node1是2017-02-14 11:17:00
最多大概10分钟左右时间，node2会同步node1的时间。

6、ceph-node2执行开机启动ntp服务
[root@ceph-node2 ~]# systemctl enable ntpd.service

7、实时同步时间
[root@ceph-node2 ~]#ntpdate 192.168.195.10

执行这个命令时，可能会出现问题，如：
13 Feb 23:55:58 ntpdate[1788]: the NTP socket is in use, exiting


使用lsof –i:123
[root@ceph-node lsof -i:123
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
ntpd 16538 ntp 16u IPv4 10940 UDP *:ntp
ntpd 16538 ntp 17u IPv6 10941 UDP *:ntp
ntpd 16538 ntp 18u IPv6 10942 UDP localhost6.localdomain6:ntp
ntpd 16538 ntp 19u IPv4 10943 UDP localhost:ntp
ntpd 16538 ntp 20u IPv4 10944 UDP 220.181.128.182:ntp
ntpd 16538 ntp 21u IPv4 10945 UDP localhost:ntp
[root@ceph-node kill -9 16538
此后，再使用ntpdate 192.168.195.10就成功了！