Reference: http://www.cnblogs.com/pipelone/archive/2009/06/17/1505002.html
yum is installed on common commands for uninstalling software: http://blog.csdn.net/kandyer/article/details/7941302
Time zone setting: http://blog.csdn.net/gtlions/article/details/7542932
Note 1:
①yum install ntp
ntp is a service, install ntp service
②yum install ntpdate
ntpdate is a command that installs the ntpdate command, a command for time synchronization
Note 2:
Install and uninstall software using yum
①Use yum to install ntp service
yum install ntp
②Uninstall the software installed using yum
yum remove ntp
Note: Since the hadoop cluster has high time requirements, the hosts in the cluster must be synchronized frequently. This document is suitable for ubuntu, redhat series.
Note: Many contents are excerpted from the Internet, and then summarized after the test. If you have any questions, you can leave a message for discussion.
1. Set the host time to be accurate (any machine can be used). //If you don't need to synchronize the network time, you can omit this step
1.1 View the local time and time zone (date)
1.2 Set the time zone (tzselect; after selecting, execute cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime) (here is the modified time zone of redhat, ubuntu is relatively simple, the command is searched online)
1.3 Modification time (date -s 00:00:00 or network synchronization: apt-get install ntpdate; ntpdate cn.pool.ntp.org)
1.4 Write time to hard disk (hwclock -w)
This completes the host time setting.
2. Time synchronization (host)
Configure the host environment (yum install ntp ) (use centos as the host, refer to ubuntu time synchronization for settings)
•vi /etc/ntp.conf
add after
server 127.127.1.0
Fudge 127.127.1.0 stratum 10
•关闭防火墙： #service iptables stop
•重新启动服务：
service ntpd stop(ubuntu是service ntp stop)
service ntpd start
这样主机准备完毕。
3.其他机器同步
•等待大概五分钟，再到其他机上同步该机器时间（先确保时区一样，否则同步以后时间也是有时区差的）
ntpdate IP地址（主机的）
Date查看时间是否同步完成。
4.根据需要，这里可以让分机器定时自动同步时间
4.1.yum install crontabs（atp-get）
4.2.crontab -e 编辑内容： * */12 * * * /usr/sbin/ntpdate 172.72.103.228（每12个小时更新一次，也可特定时间更新一次，格式可网上查找）
4.3保存退出即可，可以到/var/spool/mail/下查看记录
可能遇到的问题：no server suitable for synchronization found
参考：http://www.blogjava.net/spray/archive/2008/07/10/213964.html