ntp-实现时间同步

Posted 2022-12-09 猫二哥

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一背景介绍

已经安装好crontab和ntp，系统centos6.5，一般不是最小化安装都会有哈。集群一定要搭建时间同步机制，不然运行久了，job运行会非常慢。

二搭建内网NTP服务器，通过此服务器进行时间同步

1修改配置文件

vim /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 kod nomodify notrap nopeer noquery
restrict -6 default kod 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 -6 ::1

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

#restrict 是允许单个IP地址访问本ntp服务器，或者允许网段中的服务器访问本ntp服务器进行时间同步
restrict 192.168.247.* mask 255.255.255.0
#允许192.168.247网段的ip可以访问本ntp服务器

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#增加server 210.72.145.44 表示指定本ntp服务器的上游ntp服务器为210.72.145.44，并且设置为首先服务器。同步时间为：从上到下，写的越靠上，优先级越高。（此服务器同步不了时间，寻找下一个ntp服务器）。此IP地址是中国国家授时中心ntp服务器。
#增加server 133.100.11.8     #当上面服务器同步不了，则寻找第二个。此IP地址是日本福冈大学ntp服务器。
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 192.168.247.132    　　　　 
#local clock 如果上面的服务器都无法同步时间，就和本地系统时间同步。192.168.247.132 在这里是一个IP地址，不是网段。

#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