主服务：hadoop1 ip:192.168.1.88
其他服务器：hadoopxx ip：192.168.1.xx
1)查看软件包是否安装
rpm -q ntp
1.png
2)如果没有 那么用yum install 软件包 进行安装
3)设置开启自启动
systemctl enable ntpd
4)启动服务
systemctl start ntpd
5)设置主服务器 配置文件 标记处为修改内容
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
#111111111111
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
#111111111111
server 2.cn.pool.ntp.org
server 1.asia.pool.ntp.org
server 2.asia.pool.ntp.org
#broadcast 192.168.1.255 autokey # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 autokey # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 autokey # manycast client
#111111111111
restrict 2.cn.pool.ntp.org nomodify notrap noquery
restrict 1.asia.pool.ntp.org nomodify notrap noquery
restrict 2.asia.pool.ntp.org nomodify notrap noquery
server 127.0.0.1 # local clock
fudge 127.0.0.1 stratum 10
# Enable public key cryptography.
#crypto
includefile /etc/ntp/crypto/pw
# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography.
keys /etc/ntp/keys
# Specify the key identifiers which are trusted.
#trustedkey 4 8 42
# Specify the key identifier to use with the ntpdc utility.
#requestkey 8
# Specify the key identifier to use with the ntpq utility.
#controlkey 8
# Enable writing of statistics records.
#statistics clockstats cryptostats loopstats peerstats
# Disable the monitoring facility to prevent amplification attacks using ntpdc
# monlist command when default restrict does not include the noquery flag. See
# CVE-2013-5211 for more details.
# Note: Monitoring will not be disabled with the limited restriction flag.
disable monitor
6)重启服务
systemctl restart ntpd
7)执行 ntpstat 如果显示下边结果 正在启动
unsynchronised
time server re-starting
polling server every 64 s
8)执行 ntpstat 如果显示下边结果 已经开始运行
synchronised to NTP server (182.92.12.11) at stratum 3
time correct to within 17 ms
polling server every 64 s
9)修改非主服务器配置文件 标记处为修改内容
vi /etc/
# 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
#1111111111
server 192.168.1.88
restrict 192.168.1.88 nomodify notrap noquery
server 127.0.0.1
fudge 127.0.0.1 stratum 10
#broadcast 192.168.1.255 autokey # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 autokey # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 autokey # manycast client
# Enable public key cryptography.
#crypto
includefile /etc/ntp/crypto/pw
# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography.
keys /etc/ntp/keys
# Specify the key identifiers which are trusted.
#trustedkey 4 8 42
# Specify the key identifier to use with the ntpdc utility.
#requestkey 8
# Specify the key identifier to use with the ntpq utility.
#controlkey 8
# Enable writing of statistics records.
#statistics clockstats cryptostats loopstats peerstats
# Disable the monitoring facility to prevent amplification attacks using ntpdc
# monlist command when default restrict does not include the noquery flag. See
# CVE-2013-5211 for more details.
# Note: Monitoring will not be disabled with the limited restriction flag.
disable monitor
10)查看同步情况 ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*hadoop1 182.92.12.11 3 u 71 128 377 0.209 -1.088 0.367
localhost .INIT. 16 l - 1024 0 0.000 0.000 0.000
参数解释：
● remote： 远程NTP服务器的IP地址或域名，带 “*” 的表示本地NTP服务器与该服务器同步。
● refid： 远程NTP服务器的上层服务器的IP地址或域名。
● st： 远程NTP服务器所在的层数。
● t： 本地NTP服务器与远程NTP服务器的通信方式，u: 单播； b: 广播； l: 本地。
● when： 上一次校正时间与现在时间的差值。！！！！！！！！！！！！！
● poll： 本地NTP服务器查询远程NTP服务器的时间间隔。！！！！！！！！！！！
● reach： 是一种衡量前8次查询是否成功的位掩码值，377表示都成功，0表示不成功。
● delay： 网络延时，单位是10的-6次方秒。
● offset： 本地NTP服务器与远程NTP服务器的时间偏移。
● jitter： 查询偏差的分布值，用于表示远程NTP服务器的网络延时是否稳定，单位为10的-6次方秒。
11)测试
a. 暂时关闭ntp timedatectl set-ntp 0 //不然会报错 Failed to set time: Automatic time synchronization is enabled
b. 设置服务器时间 timedatectl set-time '2018-08-08'
c.打开ntp服务 timedatectl set-ntp 1
d.查看系统时间 date 一会儿就不是'2018-08-08'了 证明已经同步了