NTP(Network Time Protocol,網絡時間協議)是用來使網絡中的各個計算機時間同步的一種協議.它的用因而把計算機的時鐘同步到世界協調時UTC,其精度在局域網內可達0.1ms,在網絡網上絕大多數的地方其精度能夠達到1-50ms.vim
//查看一下由哪一個包提供的 [root@ntp-server ~]# yum provides chronyd Loaded plugins: product-id, search-disabled-repos, subscription-manager This system is not registered with an entitlement server. You can use subscription-manager to register. chrony-3.1-2.el7.x86_64 : An NTP client/server Repo : dvd Matched from: Filename : /usr/sbin/chronyd //安裝chrony服務 [root@ntp-server ~]# yum install chrony Loaded plugins: product-id, search-disabled-repos, subscription-manager This system is not registered with an entitlement server. You can use subscription-manager to register. dvd | 4.1 kB 00:00:00 Resolving Dependencies --> Running transaction check ---> Package chrony.x86_64 0:3.1-2.el7 will be installed --> Processing Dependency: libseccomp.so.2()(64bit) for package: chrony-3.1-2.el7.x86_64 --> Running transaction check ---> Package libseccomp.x86_64 0:2.3.1-3.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved ========================================================================================== Package Arch Version Repository Size ========================================================================================== Installing: chrony x86_64 3.1-2.el7 dvd 237 k Installing for dependencies: libseccomp x86_64 2.3.1-3.el7 dvd 56 k Transaction Summary ========================================================================================== Install 1 Package (+1 Dependent package) Total download size: 293 k Installed size: 761 k Is this ok [y/d/N]: y Downloading packages: ------------------------------------------------------------------------------------------ Total 1.6 MB/s | 293 kB 00:00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : libseccomp-2.3.1-3.el7.x86_64 1/2 Installing : chrony-3.1-2.el7.x86_64 2/2 Verifying : chrony-3.1-2.el7.x86_64 1/2 Verifying : libseccomp-2.3.1-3.el7.x86_64 2/2 Installed: chrony.x86_64 0:3.1-2.el7 Dependency Installed: libseccomp.x86_64 0:2.3.1-3.el7 Complete! //啓動服務 [root@ntp-server ~]# systemctl start chrony chrony-dnssrv@ chronyd.service chrony-wait.service [root@ntp-server ~]# systemctl start chronyd
參數 | 解釋 |
---|---|
list-timezones | 列出可用時區信息 |
set-timezone | 設置時區 |
set-ntp | 啓用NTP |
status | 查看狀態 |
[root@ntp-server ~]# timedatectl Local time: Tue 2018-08-21 14:02:35 CST Universal time: Tue 2018-08-21 06:02:35 UTC RTC time: Tue 2018-08-21 06:02:33 Time zone: Asia/Shanghai (CST, +0800) NTP enabled: n/a NTP synchronized: no RTC in local TZ: no DST active: n/a [root@ntp-server ~]# timedatectl list-timezones set-ntp set-timezone set-local-rtc set-time status [root@ntp-server ~]# timedatectl list-timezones | grep -i shanghai Asia/Shanghai //關閉NTP [root@ntp-server ~]# timedatectl set-ntp false [root@ntp-server ~]# timedatectl Local time: Tue 2018-08-21 14:15:36 CST Universal time: Tue 2018-08-21 06:15:36 UTC RTC time: Tue 2018-08-21 06:15:36 Time zone: Asia/Shanghai (CST, +0800) NTP enabled: no NTP synchronized: yes RTC in local TZ: no DST active: n/a //啓用NTP [root@ntp-server ~]# timedatectl set-ntp true [root@ntp-server ~]# timedatectl Local time: Tue 2018-08-21 14:16:02 CST Universal time: Tue 2018-08-21 06:16:02 UTC RTC time: Tue 2018-08-21 06:16:02 Time zone: Asia/Shanghai (CST, +0800) NTP enabled: yes NTP synchronized: no RTC in local TZ: no DST active: n/a //查看一下ntpdate由哪一個包提供的 [root@ntp-server ~]# yum provides ntpdate Loaded plugins: product-id, search-disabled-repos, subscription-manager This system is not registered with an entitlement server. You can use subscription-manager to register. ntpdate-4.2.6p5-25.el7_3.2.x86_64 : Utility to set the date and time via NTP Repo : dvd //若是沒有請安裝ntpdate [root@ntp-server ~]# yum install ntpdate.x86_64 Loaded plugins: product-id, search-disabled-repos, subscription-manager This system is not registered with an entitlement server. You can use subscription-manager to register. Resolving Dependencies --> Running transaction check ---> Package ntpdate.x86_64 0:4.2.6p5-25.el7_3.2 will be installed --> Finished Dependency Resolution Dependencies Resolved ========================================================================================== Package Arch Version Repository Size ========================================================================================== Installing: ntpdate x86_64 4.2.6p5-25.el7_3.2 dvd 86 k Transaction Summary ========================================================================================== Install 1 Package Total download size: 86 k Installed size: 121 k Is this ok [y/d/N]: y Downloading packages: Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : ntpdate-4.2.6p5-25.el7_3.2.x86_64 1/1 Verifying : ntpdate-4.2.6p5-25.el7_3.2.x86_64 1/1 Installed: ntpdate.x86_64 0:4.2.6p5-25.el7_3.2 Complete!
[root@ntp-server ~]# vim /etc/chrony.conf server ntp1.aliyun.com iburst server ntp2.aliyun.com iburst server ntp3.aliyun.com iburst server ntp4.aliyun.com iburst server ntp5.aliyun.com iburst server ntp6.aliyun.com iburst server ntp7.aliyun.com iburst allow 172.16.10.0/24 //驗證服務端是否能同步時間 [root@ntp-server ~]# chronyc sources -v 210 Number of sources = 1 .-- Source mode '^' = server, '=' = peer, '#' = local clock. / .- Source state '*' = current synced, '+' = combined , '-' = not combined, | / '?' = unreachable, 'x' = time may be in error, '~' = time too variable. || .- xxxx [ yyyy ] +/- zzzz || Reachability register (octal) -. | xxxx = adjusted offset, || Log2(Polling interval) --. | | yyyy = measured offset, || \ | | zzzz = estimated error. || | | \ MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* 120.25.115.20 2 6 17 22 -117us[ -948us] +/- 24ms //看一下服務器時間 [root@ntp-server ~]# date Tue Aug 21 15:31:29 CST 2018 //看一下客戶端時間 時間不對須要同步 [root@ntp-client ~]# date Fri Aug 20 14:10:28 CST 2010 //ntp服務器地址 ens35: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 172.16.10.20 netmask 255.255.255.0 broadcast 172.16.10.255 inet6 fe80::da6c:394e:1ef7:c236 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:6e:66:65 txqueuelen 1000 (Ethernet) RX packets 6 bytes 480 (480.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21 bytes 1614 (1.5 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 //客戶端同步,時間已經同步正確 [root@ntp-client ~]# ntpdate 172.16.10.20 21 Aug 15:35:10 ntpdate[2421]: step time server 172.16.10.20 offset 252552056.617240 sec You have new mail in /var/spool/mail/root [root@ntp-client ~]# date Tue Aug 21 15:35:15 CST 2018 //第一種方式設置定時任務 [root@ntp-client ~]# which ntpdate /usr/sbin/ntpdate [root@ntp-client ~]# crontab -e */2 * * * * /usr/sbin/ntpdate 172.16.10.20 &>/dev/null //第二種方式客戶端編輯配置文件服務器指向172.168.10.20 [root@ntp-client ~]# vim /etc/chrony.conf server 172.16.10.20 iburst //啓動服務查看服務運行狀態 [root@ntp-client ~]# systemctl restart chronyd [root@ntp-client ~]# systemctl status chronyd ● chronyd.service - NTP client/server Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor preset: enabled) Active: active (running) since Tue 2018-08-21 15:52:11 CST; 6s ago Docs: man:chronyd(8) man:chrony.conf(5) Process: 3012 ExecStartPost=/usr/libexec/chrony-helper update-daemon (code=exited, status=0/SUCCESS) Process: 3009 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, status=0/SUCCESS) Main PID: 3011 (chronyd) Tasks: 1 CGroup: /system.slice/chronyd.service └─3011 /usr/sbin/chronyd Aug 21 15:52:10 ntp-client systemd[1]: Starting NTP client/server... Aug 21 15:52:11 ntp-client chronyd[3011]: chronyd version 3.2 starting (+CMDMON +NTP ...G) Aug 21 15:52:11 ntp-client chronyd[3011]: Frequency -37.840 +/- 1000000.000 ppm read ...ft Aug 21 15:52:11 ntp-client systemd[1]: Started NTP client/server. Aug 21 15:52:15 ntp-client chronyd[3011]: Selected source 172.16.10.20 Hint: Some lines were ellipsized, use -l to show in full. //差很少一分鐘同步了 [root@ntp-client ~]# date Tue Aug 10 08:32:32 CST 2010 [root@ntp-client ~]# date Tue Aug 10 08:32:33 CST 2010 [root@ntp-client ~]# date Tue Aug 21 16:04:24 CST 2018 [root@ntp-client ~]# date Tue Aug 21 16:04:25 CST 2018