时间篇之centos6下修复的ntp操作(ntpd和ntpdate两个服务区别)
系统采样，本采样和命令都是在centos6.4的系统中进行
主要比较centos7和centos6之间的差异，因为大部分都开始采用centos7
但是有些老系统还采用centos6，这样我们就需要熟悉centos6下的时间处理的方法。
这里讲解ntpd和ntpdate两个服务的区别和使用方法,注意他们两个之间的区别
[root@fp-mysql-4 ~]# cat /etc/redhat-release CentOS release 6.4 (Final) [root@fp-mysql-4 ~]# uname -r 2.6.32-358.el6.x86_64
[root@fp-mysql-4 ~]# rpm -qa | grep ntp
ntpdate-4.2.4p8-3.el6.centos.x86_64
ntp-4.2.4p8-3.el6.centos.x86_64
//在centos6中是没有我们通常的命令systemctl的. systemctl作为systemd管理入口和工具在centos7中很重要，Systemd是Linux的系统和服务管理器
[root@fp-mysql-4 src]# systemctl
-bash: systemctl: command not found
//linux 2.5内核之后hz由100改成了1000
[root@fp-mysql-4 ~]# cat /boot/config-`uname -r` | grep 'CONFIG_HZ='
CONFIG_HZ=1000
//硬件计时器时间,cmos时间,rtc实时时钟芯片提供的时间.
[root@fp-mysql-4 ~]# hwclock -r
Wed 09 Mar 2022 11:21:36 AM CST -1.109619 seconds
//当前系统时间,系统定时器时间
[root@fp-mysql-4 ~]# date
Wed Mar 9 11:21:38 CST 2022
相关ntp的服务命令(ntpd和ntpdate)
[root@fp-mysql-4 ~]# ps -ef | grep ntpd root 60927 1 0 11:01 ? 00:00:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid -g root 60930 60860 0 11:01 pts/0 00:00:00 grep ntp
[root@fp-mysql-4 ~]# ps -ef|grep xntpd
root 60983 60860 0 11:24 pts/0 00:00:00 grep xntpd
//重启ntpd服务
[root@fp-mysql-4 ~]#service restart ntpd
//查看ntpd和ntpdate
[root@fp-mysql-4 ~]# service ntpd status ntpd (pid 60927) is running...
[root@fp-mysql-4 src]# service ntpdate status //没有输出任何东西
[root@fp-mysql-4 ~]# crontab -l
no crontab for root
查看当前系统运行时间情况
[root@fp-mysql-4 ~]# uptime 11:04:39 up 139 days, 17:36, 1 user, load average: 0.00, 0.00, 0.00 //运行到目前的时间 [root@fp-mysql-4 ~]# date -d "$(awk -F. '{print $1}' /proc/uptime) second ago" +"%Y-%m-%d %H:%M:%S" 2021-10-20 17:28:18
重启服务
[root@fp-mysql-4 ~]# /etc/init.d/ntpd restart Shutting down ntpd: [ OK ] Starting ntpd: [ OK ] #/etc/init.d/ntpd start #/etc/init.d/ntpd stop
查看ntpd开机启动列表
设置前
[root@fp-mysql-4 ~]# chkconfig --list ntpd
ntpd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
[root@fp-mysql-4 ~]# chkconfig --list auditd 0:off 1:off 2:on 3:on 4:on 5:on 6:off blk-availability 0:off 1:on 2:on 3:on 4:on 5:on 6:off crond 0:off 1:off 2:on 3:on 4:on 5:on 6:off ip6tables 0:off 1:off 2:on 3:on 4:on 5:on 6:off iptables 0:off 1:off 2:off 3:off 4:off 5:off 6:off lvm2-monitor 0:off 1:on 2:on 3:on 4:on 5:on 6:off mysql 0:off 1:off 2:on 3:on 4:on 5:on 6:off netconsole 0:off 1:off 2:off 3:off 4:off 5:off 6:off netfs 0:off 1:off 2:off 3:on 4:on 5:on 6:off network 0:off 1:off 2:on 3:on 4:on 5:on 6:off nfs 0:off 1:off 2:off 3:off 4:off 5:off 6:off nfslock 0:off 1:off 2:off 3:on 4:on 5:on 6:off nmb 0:off 1:off 2:on 3:on 4:on 5:on 6:off ntpd 0:off 1:off 2:off 3:off 4:off 5:off 6:off ntpdate 0:off 1:off 2:off 3:off 4:off 5:off 6:off postfix 0:off 1:off 2:on 3:on 4:on 5:on 6:off rdisc 0:off 1:off 2:off 3:off 4:off 5:off 6:off restorecond 0:off 1:off 2:off 3:off 4:off 5:off 6:off rpcbind 0:off 1:off 2:on 3:on 4:on 5:on 6:off rpcgssd 0:off 1:off 2:off 3:on 4:on 5:on 6:off rpcidmapd 0:off 1:off 2:off 3:on 4:on 5:on 6:off rpcsvcgssd 0:off 1:off 2:off 3:off 4:off 5:off 6:off rsyslog 0:off 1:off 2:on 3:on 4:on 5:on 6:off saslauthd 0:off 1:off 2:off 3:off 4:off 5:off 6:off smb 0:off 1:off 2:on 3:on 4:on 5:on 6:off sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off udev-post 0:off 1:on 2:on 3:on 4:on 5:on 6:off winbind 0:off 1:off 2:off 3:off 4:off 5:off 6:off zabbix-agent 0:off 1:off 2:on 3:on 4:on 5:on 6:off
0，1，2，3，4，5，6表示的是等级
0表示：挂起
1表示：单用户模式
2表示：无网络连接的多用户命令行模式，多用户不带nfs
3表示：有网络连接的多用户命令行模式,标准的多用户模式
4表示：不可用，未定义
5表示：带图形界面的多用户模式，x11模式
6表示：重新启动
设置后：
[root@fp-mysql-4 ~]# chkconfig --level 2345 ntpd on
[root@fp-mysql-4 ~]# chkconfig --list ntpd
ntpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
查看 /etc/ntp.conf(ntpd配置文件)
[root@fp-mysql-4 ~]# grep "^server" /etc/ntp.conf
server 0.centos.pool.ntp.org
server 1.centos.pool.ntp.org
server 2.centos.pool.ntp.org
[root@fp-mysql-4 ~]# cat /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
# 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
server 1.centos.pool.ntp.org
server 2.centos.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
# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available.
#server 127.127.1.0 # local clock
#fudge 127.127.1.0 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
查看同步情况,可以列出目前我们的NTP与相关的上层NTP的状态
[root@fp-mysql-4 ~]# ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== *120.25.115.20 10.137.53.7 2 u 17 64 173 39.543 -0.019 0.146 +139.199.214.202 100.122.36.196 2 u 42 64 377 38.537 0.483 0.116 +203.158.177.10 45.127.113.2 3 u 18 64 277 141.023 -3.701 0.130
remote：即NTP主机的IP或主机名称。注意最左边的符号，如果由“+”则代表目前正在作用钟的上层NTP，如果是“*”则表示也有连上线，不过是作为次要联机的NTP主机。
refid：参考的上一层NTP主机的地址
st：即stratum阶层
when：几秒前曾做过时间同步更新的操作
poll：下次更新在几秒之后
reach：已经向上层NTP服务器要求更新的次数
delay：网络传输过程钟延迟的时间
offset：时间补偿的结果
jitter：Linux系统时间与BIOS硬件时间的差异时间
//查看当前的状态
[root@fp-mysql-4 ~]# ntpstat
synchronised to NTP server (120.25.115.20) at stratum 3
time correct to within 7 ms
polling server every 64 s
时间重置测试
恢复之前可以
1、先停止ntpd,再进行ntpdate操作，然后让同步程序自己持续同步服务器时间
2、写入crontab，持续手工同步利用ntpdate (crontab -e编辑)
*/30 * * * * ntpdate cn.pool.ntp.org
//时间重置到 2009年，我们看看再如何恢复
[root@fp-mysql-4 ~]# date 042817252009.00
[root@fp-mysql-4 ~]# date
Tue Apr 28 17:25:00 CST 2009
[root@fp-mysql-4 ~]# date +'%Y/%m/%d %H:%M:%S'
2009/04/28 17:25:05
[root@fp-mysql-4 ~]# date
Tue Apr 28 17:25:32 CST 2009
[root@fp-mysql-4 ~]# hwclock -r
Wed 09 Mar 2022 12:57:49 PM CST -1.234650 seconds
//写入bios时间
[root@fp-mysql-4 ~]# hwclock -w
[root@fp-mysql-4 ~]# date
Tue Apr 28 17:26:07 CST 2009
[root@fp-mysql-4 ~]# hwclock -r
Tue 28 Apr 2009 05:26:13 PM CST -1.328373 seconds
[root@fp-mysql-4 ~]# /etc/init.d/ntpd restart
Shutting down ntpd: [ OK ]
Starting ntpd: [ OK ]
重启之后，并不能改变时间
[root@fp-mysql-4 ~]# date +'%Y/%m/%d %H:%M:%S'
2009/04/28 17:28:33
//得到unix时间戳
[root@fp-mysql-4 ~]# date +%s
1240910968
//根据unix时间戳再得到当前的日期和时间
[root@fp-mysql-4 ~]# date -d @1240910968
Tue Apr 28 17:29:28 CST 2009
//再检查下同步情况
[root@fp-mysql-4 ~]# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
162.159.200.1 10.28.10.82 3 u 54 64 7 160.803 4058911 4.130
178.215.228.24 131.188.3.221 2 u 53 64 3 237.201 4058911 0.209
61.239.100.101 .GPS. 1 u 53 64 3 57.424 4058911 1.114
[root@fp-mysql-4 ~]# ntpstat
unsynchronised
time server re-starting
polling server every 64 s
//因为我重启了ntpd，需要一段时间同步，unsynchronised才能变成synchronised
//过了十几分钟一切都自己恢复正常，因为已经开始同步了
[root@fp-mysql-4 ~]# ntpstat
synchronised to NTP server (178.215.228.24) at stratum 3
time correct to within 472 ms
polling server every 64 s
[root@fp-mysql-4 ~]# date
Wed Mar 9 13:09:31 CST 2022
//读取下硬件时间，发现还是硬件设置的时候，需要写入才可以
[root@fp-mysql-4 ~]# date
Wed Mar 9 13:09:31 CST 2022
[root@fp-mysql-4 ~]# hwclock -r
Tue 28 Apr 2009 05:40:29 PM CST -1.109746 seconds
[root@fp-mysql-4 ~]# hwclock -w //将当前时间和日期写入BIOS
[root@fp-mysql-4 ~]# hwclock -r
Wed 09 Mar 2022 01:11:06 PM CST -1.391015 seconds //计时方法不一样，是pm方式
设置时区命令
[root@fp-mysql-4 ~]# tzselect Please identify a location so that time zone rules can be set correctly. Please select a continent or ocean. 1) Africa 2) Americas 3) Antarctica 4) Arctic Ocean 5) Asia 6) Atlantic Ocean 7) Australia 8) Europe 9) Indian Ocean 10) Pacific Ocean 11) none - I want to specify the time zone using the Posix TZ format. #
查看北京时间
[root@fp-mysql-4 ~]# date -R //输出的 UTC + (+0800) = 北京时间
Wed, 09 Mar 2022 13:38:08 +0800
[root@fp-mysql-4 ~]# date
Wed Mar 9 13:38:32 CST 2022 //输出的是cst即北京时间
复制相关的时区文件
[root@fp-mysql-4 ~]# cp /usr/share/zoneinfo/$主时区/$次时区 /etc/localtime
例如修改时区
[root@fp-mysql-4 ~]#cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
查看文件的一些时间属性
在Linux下查看文件三种时间 1、atime(access time):最近访问文件内容时间（Last Access Time）。 2、mtime(modify time):最近修改文件内容时间（Last Modification Time）。 3、ctime(change time):最近更改文件属性（Inode内容更改）的时间，包括文件名、大小、内容、权限、属主、属组等（Last Change Time）。
//stat命令
[root@fp-mysql-4 src]# stat changeconf.sh
File: `changeconf.sh'
Size: 217 Blocks: 8 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 1445783 Links: 1 //通过inode也可以删除文件
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2017-03-22 17:13:38.123979187 +0800
Modify: 2017-03-22 17:12:48.449979192 +0800
Change: 2017-03-22 17:12:48.449979192 +0800
1.输入“touch test.txt”创建新文件，输入“stat test.txt”即可查看文件filetime.txt的时间属性。
备注：新创建文件的三种时间抓取当前时间，本例中为2019-01-05 19:42:36。
[root@fp-mysql-4 src]# stat test.txt
File: `test.txt'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: fd00h/64768d Inode: 1447438 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-03-09 13:45:06.797572818 +0800
Modify: 2022-03-09 13:45:06.797572818 +0800
Change: 2022-03-09 13:45:06.797572818 +0800
//修改文件之后
[root@fp-mysql-4 src]# vi test.txt
[root@fp-mysql-4 src]# stat test.txt
File: `test.txt'
Size: 4 Blocks: 8 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 1447440 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-03-09 13:45:30.343700307 +0800
Modify: 2022-03-09 13:45:30.343700307 +0800
Change: 2022-03-09 13:45:30.352700267 +0800
//输入“ls -lc test.txt”可查看文件test.txt的ctime。
[root@fp-mysql-4 src]# ls -lc test.txt
-rw-r--r-- 1 root root 4 Mar 9 13:45 test.txt
//输入“ls -lu test.txt”可查看文件new.txt的atime。
[root@fp-mysql-4 src]# ls -lu test.txt
-rw-r--r-- 1 root root 4 Mar 9 13:45 test.txt
//输入“ls -l test.txt”可查看文件new.txt的mtime。
-rw-r--r-- 1 root root 4 Mar 9 13:45 test.txt
二、使用ntpdate
//重启ntpdate的话会出现 [root@fp-mysql-4 src]# /etc/init.d/ntpdate restart ntpdate: Synchronizing with time server: [FAILED] [root@fp-mysql-4 src]# service ntpdate start ntpdate: Synchronizing with time server: [FAILED] //这个是由于什么原因呢？ 注意这里很重要，首先你要停止 ntpd服务，这里演示一下 [root@fp-mysql-4 src]# service ntpdate start ntpdate: Synchronizing with time server: [FAILED] [root@fp-mysql-4 src]# service ntpd stop Shutting down ntpd: [ OK ] [root@fp-mysql-4 src]# service ntpdate start ntpdate: Synchronizing with time server: [ OK ] //这样你就可以在crontab -e 编辑你的任务比如： */5 * * * * /usr/sbin/ntpdate ntp.fudan.edu ，就相当于每5秒钟，手工自动执行一次
//同时要注意是，一旦你启动了ntpdate,ntpd这个服务就可以自有的关闭和启动了。 所以有个前置的条件是，启动ntpdate之前必须关闭ntpd.
设置ntpdate开机启动
[root@fp-mysql-4 ~]# chkconfig --level 2345 ntpdate on [root@fp-mysql-4 ~]# chkconfig --list ntpdate ntpdate 0:off 1:off 2:on 3:on 4:on 5:on 6:off