时间篇之centos6下修复的ntp操作(ntpd和ntpdate两个服务区别)

[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  //ntp包，包括两个服务.
ntpdate-4.2.4p8-3.el6.centos.x86_64   //ntpdate服务
ntp-4.2.4p8-3.el6.centos.x86_64       //ntpd服务

//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

[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

[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

[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

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

注意：centos7中改命令改成了
 1、systemctl list-unit-files  
 2、[root@ht23 ~]# systemctl list-unit-files | grep ntp
  ntpd.service enabled
  ntpdate.service disabled
 3、[root@ht23 ~]#systemctl is-enabled ntpdate

[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

[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

[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.
#

[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

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

//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.

[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