为什么Linux系统时间老是不准

一、使用 NTP 服务时间同步

安装 ntp

[root@node~]#yum-yinstallntp

启动 ntp 服务

[root@node~]#systemctlstartntpd
[root@node~]#systemctlenablentpd
Createdsymlinkfrom/etc/systemd/system/multi-user.target.wants/ntpd.serviceto/usr/lib/systemd/system/ntpd.service.

查看 ntp 服务

[root@node~]#systemctlstatusntpd
●ntpd.service-NetworkTimeService
Loaded:loaded(/usr/lib/systemd/system/ntpd.service;enabled;vendorpreset:disabled)
Active:active(running)sinceThu2022-08-0408:00:47CST;7hleft
MainPID:20746(ntpd)
Tasks:1
Memory:768.0K
CGroup:/system.slice/ntpd.service
└─20746/usr/sbin/ntpd-untp:ntp-g

Aug0408:00:47nodentpd[20746]:Listennormallyon6lo::1UDP123
Aug0408:00:47nodentpd[20746]:Listennormallyon7ens33fe80::8a83:7297:7cb8:9934UDP123
Aug0408:00:47nodentpd[20746]:Listeningonroutingsocketonfd#24forinterfaceupdates
Aug0408:00:47nodesystemd[1]:StartedNetworkTimeService.
Aug0408:00:47nodentpd[20746]:0.0.0.0c01606restart
Aug0408:00:47nodentpd[20746]:0.0.0.0c01202freq_setkernel0.000PPM
Aug0408:00:47nodentpd[20746]:0.0.0.0c01101freq_not_set
Aug0408:00:56nodentpd[20746]:0.0.0.0c61c0cclock_step-28798.353463s
Aug0400:00:57nodentpd[20746]:0.0.0.0c61404freq_mode
Aug0400:00:58nodentpd[20746]:0.0.0.0c61808no_sys_peer

修改 ntp.conf 文件

[root@node~]#vim/etc/ntp.conf
[root@node~]#grepserver/etc/ntp.conf
#Usepublicserversfromthepool.ntp.orgproject.
#server0.centos.pool.ntp.orgiburst
serverntp.aliyun.comiburst
#broadcast192.168.1.255autokey#broadcastserver
#broadcast224.0.1.1autokey#multicastserver
#manycastserver239.255.254.254#manycastserver

重启服务

[root@node~]#systemctlrestartntpd

检查同步状态

[root@node~]#ntpq-p
remoterefidsttwhenpollreachdelayoffsetjitter
==============================================================================
203.107.6.88100.107.25.1142u264130.975149.4990.393

二、使用 ntpdate 同步

使用 ntpd 命令同步

[root@node~]#ntpdatentp.aliyun.com
4Aug0017ntpdate[20924]:adjusttimeserver203.107.6.88offset-0.001543sec

查看时间

[root@node~]#date
ThuAug40046CST2022

三、处理 ntpdate 同步失败报错方法

报错信息

cna02:~#ntpdatentp1.aliyun.com
4Aug0741ntpdate[18694]:theNTPsocketisinuse,exiting

处理方法

cna02:~#servicentpdstop
Redirectingto/bin/systemctlstopntpd.service

重新同步

cna02:~#ntpdatentp1.aliyun.com
3Aug2336ntpdate[28980]:steptimeserver120.25.115.20offset-28911.609110sec

查看时间是否正确

cna02:~#date
WedAug32341CST2022

四、使用 chrony 服务时间同步

安装 chrony

[root@node~]#yum-yinstallchrony
Loadedplugins:fastestmirror,langpacks
Loadingmirrorspeedsfromcachedhostfile
*base:mirrors.bfsu.edu.cn
*extras:mirrors.bfsu.edu.cn
*updates:mirrors.bfsu.edu.cn
ResolvingDependencies
-->Runningtransactioncheck
--->Packagechrony.x86_640:3.2-2.el7willbeupdated
--->Packagechrony.x86_640:3.4-1.el7willbeanupdate
-->FinishedDependencyResolution

DependenciesResolved

===============================================================================================================================================================================
PackageArchVersionRepositorySize
===============================================================================================================================================================================
Updating:
chronyx86_643.4-1.el7base251k

TransactionSummary
===============================================================================================================================================================================
Upgrade1Package

Totaldownloadsize:251k
Downloadingpackages:
NoPrestometadataavailableforbase
chrony-3.4-1.el7.x86_64.rpm|251kB00:00:00
Runningtransactioncheck
Runningtransactiontest
Transactiontestsucceeded
Runningtransaction
Updating:chrony-3.4-1.el7.x86_641/2
Cleanup:chrony-3.2-2.el7.x86_642/2
Verifying:chrony-3.4-1.el7.x86_641/2
Verifying:chrony-3.2-2.el7.x86_642/2

Updated:
chrony.x86_640:3.4-1.el7

Complete!

启动 chrony 服务

[root@node~]#systemctlenable--nowchronyd
Createdsymlinkfrom/etc/systemd/system/multi-user.target.wants/chronyd.serviceto/usr/lib/systemd/system/chronyd.service.

查看 chrony 状态

[root@node~]#systemctlstatuschronyd
●chronyd.service-NTPclient/server
Loaded:loaded(/usr/lib/systemd/system/chronyd.service;enabled;vendorpreset:enabled)
Active:active(running)sinceThu2022-08-040027CST;29sago
Docs:man:chronyd(8)
man:chrony.conf(5)
Process:21136ExecStartPost=/usr/libexec/chrony-helperupdate-daemon(code=exited,status=0/SUCCESS)
Process:21132ExecStart=/usr/sbin/chronyd$OPTIONS(code=exited,status=0/SUCCESS)
MainPID:21134(chronyd)
Tasks:1
Memory:364.0K
CGroup:/system.slice/chronyd.service
└─21134/usr/sbin/chronyd

Aug0400:12:27nodesystemd[1]:StartingNTPclient/server...
Aug0400:12:27nodechronyd[21134]:chronydversion3.4starting(+CMDMON+NTP+REFCLOCK+RTC+PRIVDROP+SCFILTER+SIGND+ASYNCDNS+SECHASH+IPV6+DEBUG)
Aug0400:12:27nodesystemd[1]:StartedNTPclient/server.
Aug0400:12:35nodechronyd[21134]:Selectedsource193.182.111.141
Aug0400:12:35nodechronyd[21134]:Source78.46.102.180replacedwith94.237.64.20

修改配置文件

[root@node~]#grepserver/etc/chrony.conf
#Usepublicserversfromthepool.ntp.orgproject.
#server0.centos.pool.ntp.orgiburst
#server1.centos.pool.ntp.orgiburst
#server3.centos.pool.ntp.orgiburst
serverntp1.aliyun.comiburst

重启服务

[root@node~]#systemctlrestartchronyd

检查时间同步状态

[root@node~]#chronycsources
210Numberofsources=1
MSName/IPaddressStratumPollReachLastRxLastsample
===============================================================================
^*120.25.115.20267126+751us[+1549us]+/-19ms

五、手动修改时间

修改时间方法 1

[root@node~]#date-s"2012-05-230101"
WedMay230101CST2012
[root@node~]#date
WedMay230105CST2012

修改时间方法 2

修改时间顺序为月日时分年. 秒

[root@tianyi~]#date090621282021.28
MonSep62128CST2021

硬件时间向系统时间同步

[root@node~]#hwclock-w

按格式输出时间

[root@node~]#date"+%Y-%m-%d%H:%M:%S"
2012-05-230110

设置时区

[root@tianyibackups]#timedatectllist-timezones|grepShanghai
Asia/Shanghai
[root@tianyibackups]#timedatectlset-timezoneAsia/Shanghai