Linux集群部署自定义时间同步服务器(ntpd)
Linux集群部署自定义时间同步服务器(ntpd)
作者:尹正杰
版权声明:原创作品,谢绝转载!否则将追究法律责任。
身为一名运维人员,在搭建集群的时候,第一步需要做的就是同步每个机器的时间,尤其是在部署类似VPN这种服务,你不同步时间是会遇到坑的,我之前在部署openVPN是就遇到过类似的问题,我们通常对时间同步的方式:找一个机器(当然这个服务器可以是局域网的也可以是广域网的哟),作为时间服务器,所有的机器与这台集群时间进行定时的同步,比如,每隔十分钟,同步一次时间。
一.安装ntp软件
1>.操作平台
[yinzhengjie@node101 ~]$ free -m total used free shared buff/cache available Mem: 7808 133 7444 8 230 7465 Swap: 2047 0 2047 [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ uname -r 3.10.0-327.el7.x86_64 [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ uname -m x86_64 [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ hostname -i 172.30.1.101 [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ cat /etc/hosts | grep yinzhengjie 172.30.1.101 node101.yinzhengjie.org.cn 172.30.1.102 node102.yinzhengjie.org.cn 172.30.1.103 node103.yinzhengjie.org.cn [yinzhengjie@node101 ~]$
2>.检查ntp软件是否安装
[yinzhengjie@s101 ~]$ rpm -qa | grep ntp #如果没有内容输出,则说明没有按照ntp服务
3>.使用root权限安装ntp软件
[yinzhengjie@s101 ~]$ sudo yum -y install ntp [sudo] password for yinzhengjie: Loaded plugins: fastestmirror base | 3.6 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 (1/2): extras/7/x86_64/primary_db | 174 kB 00:00:00 (2/2): updates/7/x86_64/primary_db | 5.2 MB 00:00:02 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: ftp.sjtu.edu.cn Resolving Dependencies --> Running transaction check ---> Package ntp.x86_64 0:4.2.6p5-28.el7.centos will be installed --> Processing Dependency: ntpdate = 4.2.6p5-28.el7.centos for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Processing Dependency: libcrypto.so.10(OPENSSL_1.0.2)(64bit) for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Processing Dependency: libopts.so.25()(64bit) for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Running transaction check ---> Package autogen-libopts.x86_64 0:5.18-5.el7 will be installed ---> Package ntpdate.x86_64 0:4.2.6p5-28.el7.centos will be installed ---> Package openssl-libs.x86_64 1:1.0.1e-42.el7.9 will be updated --> Processing Dependency: openssl-libs(x86-64) = 1:1.0.1e-42.el7.9 for package: 1:openssl-1.0.1e-42.el7.9.x86_64 ---> Package openssl-libs.x86_64 1:1.0.2k-12.el7 will be an update --> Running transaction check ---> Package openssl.x86_64 1:1.0.1e-42.el7.9 will be updated ---> Package openssl.x86_64 1:1.0.2k-12.el7 will be an update --> Finished Dependency Resolution Dependencies Resolved ======================================================================================================================================================================================= Package Arch Version Repository Size ======================================================================================================================================================================================= Installing: ntp x86_64 4.2.6p5-28.el7.centos base 549 k Installing for dependencies: autogen-libopts x86_64 5.18-5.el7 base 66 k ntpdate x86_64 4.2.6p5-28.el7.centos base 86 k Updating for dependencies: openssl x86_64 1:1.0.2k-12.el7 base 492 k openssl-libs x86_64 1:1.0.2k-12.el7 base 1.2 M Transaction Summary ======================================================================================================================================================================================= Install 1 Package (+2 Dependent packages) Upgrade ( 2 Dependent packages) Total download size: 2.4 M Downloading packages: Delta RPMs disabled because /usr/bin/applydeltarpm not installed. (1/5): ntpdate-4.2.6p5-28.el7.centos.x86_64.rpm | 86 kB 00:00:00 (2/5): autogen-libopts-5.18-5.el7.x86_64.rpm | 66 kB 00:00:00 (3/5): openssl-1.0.2k-12.el7.x86_64.rpm | 492 kB 00:00:00 (4/5): ntp-4.2.6p5-28.el7.centos.x86_64.rpm | 549 kB 00:00:00 (5/5): openssl-libs-1.0.2k-12.el7.x86_64.rpm | 1.2 MB 00:00:01 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Total 1.6 MB/s | 2.4 MB 00:00:01 Running transaction check Running transaction test Transaction test succeeded Running transaction Updating : 1:openssl-libs-1.0.2k-12.el7.x86_64 1/7 Installing : ntpdate-4.2.6p5-28.el7.centos.x86_64 2/7 Installing : autogen-libopts-5.18-5.el7.x86_64 3/7 Installing : ntp-4.2.6p5-28.el7.centos.x86_64 4/7 Updating : 1:openssl-1.0.2k-12.el7.x86_64 5/7 Cleanup : 1:openssl-1.0.1e-42.el7.9.x86_64 6/7 Cleanup : 1:openssl-libs-1.0.1e-42.el7.9.x86_64 7/7 Verifying : ntpdate-4.2.6p5-28.el7.centos.x86_64 1/7 Verifying : ntp-4.2.6p5-28.el7.centos.x86_64 2/7 Verifying : autogen-libopts-5.18-5.el7.x86_64 3/7 Verifying : 1:openssl-1.0.2k-12.el7.x86_64 4/7 Verifying : 1:openssl-libs-1.0.2k-12.el7.x86_64 5/7 Verifying : 1:openssl-libs-1.0.1e-42.el7.9.x86_64 6/7 Verifying : 1:openssl-1.0.1e-42.el7.9.x86_64 7/7 Installed: ntp.x86_64 0:4.2.6p5-28.el7.centos Dependency Installed: autogen-libopts.x86_64 0:5.18-5.el7 ntpdate.x86_64 0:4.2.6p5-28.el7.centos Dependency Updated: openssl.x86_64 1:1.0.2k-12.el7 openssl-libs.x86_64 1:1.0.2k-12.el7 Complete! [yinzhengjie@s101 ~]$
4>.检查是否安装成功
[yinzhengjie@s101 ~]$ rpm -qa | grep ntp #有内容输出,则说明安装成功,安装完毕会有以下出输出内容 ntpdate-4.2.6p5-28.el7.centos.x86_64 ntp-4.2.6p5-28.el7.centos.x86_64 [yinzhengjie@s101 ~]$
二.集群中时间服务器配置(需要root权限)
1>.设置本地网络上的主机不受限制
[yinzhengjie@node101 ~]$ grep \#restrict /etc/ntp.conf #查看修改前的内容 #restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ sudo sed -i 's@\#restrict@restrict@' /etc/ntp.conf #编辑配置文件,将注释去掉,表示启用授权功能 [sudo] password for yinzhengjie: [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ grep 192.168.1.0 /etc/ntp.conf #查看修改后的内容 restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap [yinzhengjie@node101 ~]$ [yinzhengjie@node101 ~]$ su root Password: [root@node101 yinzhengjie]# [root@node101 yinzhengjie]# sed -i 's#192.168.1.0#172.30.1.0#' /etc/ntp.conf #授权只有172.30.1.0网段的服务器可以来同步时间,其实我发现不修改咱能也能通过ntpdate来进行时间同步. [root@node101 yinzhengjie]#
2>.注释默认的时间服务器(设置为不采用公共的服务器)
[yinzhengjie@s101 ~]$ grep ^server /etc/ntp.conf #查看官方默认的时间服务器 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 [yinzhengjie@s101 ~]$ [yinzhengjie@s101 ~]$ sudo sed -i 's@^server@#server@' /etc/ntp.conf #编辑配置文件,将官方的配置注释掉 [sudo] password for yinzhengjie: [yinzhengjie@s101 ~]$ [yinzhengjie@s101 ~]$ grep ^#server /etc/ntp.conf #再次查看,检验是否修改成功 #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 [yinzhengjie@s101 ~]$
3>.设置自定义时间服务器(添加默认的一个内部时钟数据,使用它为局域网用户提供服务)
[yinzhengjie@s101 ~]$ su root Password: [root@s101 yinzhengjie]# echo "#Add by yinzhengjie" >> /etc/ntp.conf [root@s101 yinzhengjie]# echo "server 127.127.1.0" >> /etc/ntp.conf #将本地时间作为时间同步源 [root@s101 yinzhengjie]# echo "fudge 127.127.1.0 stratum 10" >> /etc/ntp.conf #指定间隔更新时间,我这里指定的是10分钟。stratum(层级)的值不能太大,如果要向上级NTP更新可以设成2. [root@s101 yinzhengjie]# [root@s101 yinzhengjie]# tail -3 /etc/ntp.conf #Add by yinzhengjie server 127.127.1.0 fudge 127.127.1.0 stratum 10 [root@s101 yinzhengjie]# [root@s101 yinzhengjie]# exit exit [yinzhengjie@s101 ~]$
4>.修改/etc/sysconfig/ntpd 文件
[yinzhengjie@s101 ~]$ su root Password: [root@s101 yinzhengjie]# cat /etc/sysconfig/ntpd # Command line options for ntpd OPTIONS="-g" [root@s101 yinzhengjie]# echo SYNC_HWCLOCK=yes >> /etc/sysconfig/ntpd #让硬件时间和系统时间一起同步 [root@s101 yinzhengjie]# [root@s101 yinzhengjie]# cat /etc/sysconfig/ntpd # Command line options for ntpd OPTIONS="-g" SYNC_HWCLOCK=yes [root@s101 yinzhengjie]# exit exit [yinzhengjie@s101 ~]$
5>.启动ntpd
[root@node101 yinzhengjie]# systemctl start ntpd #启动ntp服务 [root@node101 yinzhengjie]# [root@node101 yinzhengjie]# systemctl enable ntpd #设置开机自启 Created symlink from /etc/systemd/system/multi-user.target.wants/ntpd.service to /usr/lib/systemd/system/ntpd.service. [root@node101 yinzhengjie]# [root@node101 yinzhengjie]# systemctl status ntpd ● ntpd.service - Network Time Service Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled; vendor preset: disabled) Active: active (running) since Mon 2018-10-01 13:00:24 CST; 9min ago Main PID: 2760 (ntpd) CGroup: /system.slice/ntpd.service └─2760 /usr/sbin/ntpd -u ntp:ntp -g Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: ntp_io: estimated max descriptors: 1024, initial socket boundary: 16 Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: Listen and drop on 0 v4wildcard 0.0.0.0 UDP 123 Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: Listen and drop on 1 v6wildcard :: UDP 123 Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: Listen normally on 2 lo 127.0.0.1 UDP 123 Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: Listen normally on 3 ens33 172.30.1.101 UDP 123 Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: Listening on routing socket on fd #20 for interface updates Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: 0.0.0.0 c016 06 restart Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: 0.0.0.0 c012 02 freq_set kernel 0.000 PPM Oct 01 13:00:24 node101.yinzhengjie.org.cn ntpd[2760]: 0.0.0.0 c011 01 freq_not_set Oct 01 13:00:31 node101.yinzhengjie.org.cn ntpd[2760]: 0.0.0.0 c614 04 freq_mode [root@node101 yinzhengjie]#
三.集群中其它节点(ntpd客户端)配置(安装后需要启动ntpd)
1>.安装ntp服务
[yinzhengjie@s102 ~]$ sudo yum -y install ntp We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things: #1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility. [sudo] password for yinzhengjie: Loaded plugins: fastestmirror base | 3.6 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 (1/2): extras/7/x86_64/primary_db | 174 kB 00:00:00 (2/2): updates/7/x86_64/primary_db | 5.2 MB 00:00:02 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: ftp.sjtu.edu.cn Resolving Dependencies --> Running transaction check ---> Package ntp.x86_64 0:4.2.6p5-28.el7.centos will be installed --> Processing Dependency: ntpdate = 4.2.6p5-28.el7.centos for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Processing Dependency: libcrypto.so.10(OPENSSL_1.0.2)(64bit) for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Processing Dependency: libopts.so.25()(64bit) for package: ntp-4.2.6p5-28.el7.centos.x86_64 --> Running transaction check ---> Package autogen-libopts.x86_64 0:5.18-5.el7 will be installed ---> Package ntpdate.x86_64 0:4.2.6p5-28.el7.centos will be installed ---> Package openssl-libs.x86_64 1:1.0.1e-42.el7.9 will be updated --> Processing Dependency: openssl-libs(x86-64) = 1:1.0.1e-42.el7.9 for package: 1:openssl-1.0.1e-42.el7.9.x86_64 ---> Package openssl-libs.x86_64 1:1.0.2k-12.el7 will be an update --> Running transaction check ---> Package openssl.x86_64 1:1.0.1e-42.el7.9 will be updated ---> Package openssl.x86_64 1:1.0.2k-12.el7 will be an update --> Finished Dependency Resolution Dependencies Resolved ======================================================================================================================================================================================= Package Arch Version Repository Size ======================================================================================================================================================================================= Installing: ntp x86_64 4.2.6p5-28.el7.centos base 549 k Installing for dependencies: autogen-libopts x86_64 5.18-5.el7 base 66 k ntpdate x86_64 4.2.6p5-28.el7.centos base 86 k Updating for dependencies: openssl x86_64 1:1.0.2k-12.el7 base 492 k openssl-libs x86_64 1:1.0.2k-12.el7 base 1.2 M Transaction Summary ======================================================================================================================================================================================= Install 1 Package (+2 Dependent packages) Upgrade ( 2 Dependent packages) Total download size: 2.4 M Downloading packages: Delta RPMs disabled because /usr/bin/applydeltarpm not installed. (1/5): autogen-libopts-5.18-5.el7.x86_64.rpm | 66 kB 00:00:00 (2/5): ntpdate-4.2.6p5-28.el7.centos.x86_64.rpm | 86 kB 00:00:00 (3/5): openssl-1.0.2k-12.el7.x86_64.rpm | 492 kB 00:00:00 (4/5): ntp-4.2.6p5-28.el7.centos.x86_64.rpm | 549 kB 00:00:00 (5/5): openssl-libs-1.0.2k-12.el7.x86_64.rpm | 1.2 MB 00:00:02 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Total 1.0 MB/s | 2.4 MB 00:00:02 Running transaction check Running transaction test Transaction test succeeded Running transaction Updating : 1:openssl-libs-1.0.2k-12.el7.x86_64 1/7 Installing : ntpdate-4.2.6p5-28.el7.centos.x86_64 2/7 Installing : autogen-libopts-5.18-5.el7.x86_64 3/7 Installing : ntp-4.2.6p5-28.el7.centos.x86_64 4/7 Updating : 1:openssl-1.0.2k-12.el7.x86_64 5/7 Cleanup : 1:openssl-1.0.1e-42.el7.9.x86_64 6/7 Cleanup : 1:openssl-libs-1.0.1e-42.el7.9.x86_64 7/7 Verifying : ntpdate-4.2.6p5-28.el7.centos.x86_64 1/7 Verifying : ntp-4.2.6p5-28.el7.centos.x86_64 2/7 Verifying : autogen-libopts-5.18-5.el7.x86_64 3/7 Verifying : 1:openssl-1.0.2k-12.el7.x86_64 4/7 Verifying : 1:openssl-libs-1.0.2k-12.el7.x86_64 5/7 Verifying : 1:openssl-libs-1.0.1e-42.el7.9.x86_64 6/7 Verifying : 1:openssl-1.0.1e-42.el7.9.x86_64 7/7 Installed: ntp.x86_64 0:4.2.6p5-28.el7.centos Dependency Installed: autogen-libopts.x86_64 0:5.18-5.el7 ntpdate.x86_64 0:4.2.6p5-28.el7.centos Dependency Updated: openssl.x86_64 1:1.0.2k-12.el7 openssl-libs.x86_64 1:1.0.2k-12.el7 Complete! [yinzhengjie@s102 ~]$
2>.编写时间同步脚本(在其他机器配置1分钟与时间服务器同步一次)
[yinzhengjie@s102 ~]$ sudo crontab -e #编辑同步脚本 We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things: #1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility. [sudo] password for yinzhengjie: no crontab for root - using an empty one crontab: installing new crontab [yinzhengjie@s102 ~]$ sudo crontab -l #查看已经编辑的周期执行任务 */1 * * * * /usr/sbin/ntpdate s101 #注意,在crontab中的命令必须得写绝对路径,否则会抛异常说命令找不到哟! [yinzhengjie@s102 ~]$
3>.其它节点配置重复以上操作
注意需要使用root 权限,如果你没有root权限,如果你在公司没有root权限的话,可以请求运维帮你提供相关命令的sudo权限哟,其它机器的配置只需要安装ntp服务和编写周期性任务脚本即可。我上面就配置了一个节点,其它节点我也做了类似的调整。
四.验证各节点是否与时间服务器同步
1>.编写管理集群的"xcall.sh"脚本
以下脚本的执行需要配置无秘钥登录,关于如何配置无秘钥登录可以参考我之前的笔记:https://www.cnblogs.com/yinzhengjie/p/9065191.html。
[yinzhengjie@s101 ~]$ more `which xcall.sh` #!/bin/bash #@author :yinzhengjie #blog:http://www.cnblogs.com/yinzhengjie #EMAIL:y1053419035@qq.com #判断用户是否传参 if [ $# -lt 1 ];then echo "请输入参数" exit fi #获取用户输入的命令 cmd=$@ for (( i=101;i<=105;i++ )) do #使终端变绿色 tput setaf 2 echo ============= s$i $cmd ============ #使终端变回原来的颜色,即白灰色 tput setaf 7 #远程执行命令 ssh s$i $cmd #判断命令是否执行成功 if [ $? == 0 ];then echo "命令执行成功" fi done [yinzhengjie@s101 ~]$
2>.检查各个节点配置
[yinzhengjie@s101 ~]$ sudo xcall.sh crontab -l sudo: timestamp too far in the future: Aug 21 10:54:52 2018 We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things: #1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility. [sudo] password for yinzhengjie: [root@s101 yinzhengjie]# xcall.sh crontab -l ============= s101 crontab -l ============ no crontab for root ============= s102 crontab -l ============ */1 * * * * /usr/sbin/ntpdate s101 命令执行成功 ============= s103 crontab -l ============ */1 * * * * /usr/sbin/ntpdate s101 命令执行成功 ============= s104 crontab -l ============ */1 * * * * /usr/sbin/ntpdate s101 命令执行成功 ============= s105 crontab -l ============ */1 * * * * /usr/sbin/ntpdate s101 命令执行成功 [root@s101 yinzhengjie]# [root@s101 yinzhengjie]# exit exit [yinzhengjie@s101 ~]$ [yinzhengjie@s101 ~]$
3>.检查集群当前服务器时间
[yinzhengjie@s101 ~]$ xcall.sh date ============= s101 date ============ Sun Oct 1 11:29:26 EDT 2017 命令执行成功 ============= s102 date ============ Sun Oct 1 11:29:26 EDT 2017 命令执行成功 ============= s103 date ============ Sun Oct 1 11:29:26 EDT 2017 命令执行成功 ============= s104 date ============ Sun Oct 1 11:29:26 EDT 2017 命令执行成功 ============= s105 date ============ Sun Oct 1 11:29:26 EDT 2017 命令执行成功 [yinzhengjie@s101 ~]$
4>.修改服务器时间,并查看其它节点是否跟随时间服务器的修改而修改
[yinzhengjie@s101 ~]$ sudo date -s "2018-8-21 14:14:11" [sudo] password for yinzhengjie: Tue Aug 21 14:14:11 EDT 2018 [yinzhengjie@s101 ~]$ [yinzhengjie@s101 ~]$ [yinzhengjie@s101 ~]$ xcall.sh date ============= s101 date ============ Tue Aug 21 14:16:51 EDT 2018 命令执行成功 ============= s102 date ============ Tue Aug 21 14:16:51 EDT 2018 命令执行成功 ============= s103 date ============ Tue Aug 21 14:16:52 EDT 2018 命令执行成功 ============= s104 date ============ Tue Aug 21 14:16:52 EDT 2018 命令执行成功 ============= s105 date ============ Tue Aug 21 14:16:52 EDT 2018 命令执行成功 [yinzhengjie@s101 ~]$
五.将系统时间和服务器硬件时间同步
[root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# hwclock #注意,这是查看硬件时间 Mon 10 Jun 2019 09:29:11 PM CST -0.694751 seconds [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# date #查看系统时间 Mon Jun 10 21:29:15 CST 2019 [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# date -s "2019-06-10 14:44:00" #我们修改了系统时间 Mon Jun 10 14:44:00 CST 2019 [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# date #系统时间的确是发生了修改 Mon Jun 10 14:44:02 CST 2019 [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# hwclock #硬件时间却没有跟着变化 Mon 10 Jun 2019 09:29:47 PM CST -0.803342 seconds [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# date Mon Jun 10 14:44:09 CST 2019 [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# hwclock -w #于是我们把系统时间和硬件时间进行同步 [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# hwclock #再次查看硬件时间 Mon 10 Jun 2019 02:44:21 PM CST -0.600744 seconds [root@node101.yinzhengjie.org.cn ~]# [root@node101.yinzhengjie.org.cn ~]# date Mon Jun 10 14:44:25 CST 2019 [root@node101.yinzhengjie.org.cn ~]#