參考鏈接：
[阿里巴巴開源鏡像站](https://developer.aliyun.com/mirror/?spm=a2c6h.13651102.0.0.38221b11i1SzUL&serviceType=mirror)
[NTP下載安裝教程](https://developer.aliyun.com/mirror/NTP?spm=a2c6h.13651102.0.0.38221b11LFNKaZ)
一、NTP服務(wù)器介紹
網(wǎng)絡(luò)時間協(xié)議（Network Time Protocol，NTP）服務(wù)器，也就是日常所說的NTP服務(wù)器，用來提供同步時間服務(wù)。在生產(chǎn)環(huán)境中，很多人都會忽略時間問題，實際上服務(wù)器、網(wǎng)絡(luò)設(shè)備等，特別是Linux操作系統(tǒng)和虛擬化平臺的時間不同步會導(dǎo)致很多問題。那么搭建一臺NTP服務(wù)器就非常重要，生產(chǎn)環(huán)境中的設(shè)備可以直接與NTP服務(wù)器進行時間同步，NTP服務(wù)器本身也可以訪問互連的NTP服務(wù)器進行同步。NTP服務(wù)器可以是物理服務(wù)器，也可以是虛擬機。
二、安裝NTP服務(wù)組件
在Linux服務(wù)器（如，CentOS、Ubuntu等操作系統(tǒng)）上，使用命令進行安裝。
本實驗以CentOS 7 Linux環(huán)境進行演示操作記錄。
YUM源已更新成阿里云開源鏡像站里的CentOS鏡像，加速快捷訪問。
```
[root@ntp ~]# yum clean allLoaded plugins: fastestmirror
Cleaning repos: base extras updates
Cleaning up list of fastest mirrors
[root@ntp ~]# yum repolistLoaded plugins: fastestmirror
Determining fastest mirrors
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
base? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 3.6 kB? 00:00:00? ?
extras? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 2.9 kB? 00:00:00? ?
updates? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 2.9 kB? 00:00:00? ?
(1/4): base/7/x86_64/group_gz? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 153 kB? 00:00:00? ?
(2/4): extras/7/x86_64/primary_db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 243 kB? 00:00:00? ?
(3/4): updates/7/x86_64/primary_db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |? 12 MB? 00:00:01? ?
(4/4): base/7/x86_64/primary_db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 6.1 MB? 00:00:03? ?
repo id? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? repo name? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? status
base/7/x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? CentOS-7 - Base - mirrors.aliyun.com? ? ? ? ? ? ? ? ? ? ? ? ? ? 10,072
extras/7/x86_64? ? ? ? ? ? ? ? ? ? ? ? ? CentOS-7 - Extras - mirrors.aliyun.com? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 500
updates/7/x86_64? ? ? ? ? ? ? ? ? ? ? ? ? CentOS-7 - Updates - mirrors.aliyun.com? ? ? ? ? ? ? ? ? ? ? ? ? 2,963
repolist: 13,535
[root@ntp ~]#
```
執(zhí)行yum install -y ntp命令，進行ntp組件安裝。
```
[root@ntp ~]# yum install -y ntpLoaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package ntp.x86_64 0:4.2.6p5-29.el7.centos.2 will be installed
--> Processing Dependency: ntpdate = 4.2.6p5-29.el7.centos.2 for package: ntp-4.2.6p5-29.el7.centos.2.x86_64
--> Processing Dependency: libopts.so.25()(64bit) for package: ntp-4.2.6p5-29.el7.centos.2.x86_64
--> Running transaction check
---> Package autogen-libopts.x86_64 0:5.18-5.el7 will be installed
---> Package ntpdate.x86_64 0:4.2.6p5-29.el7.centos.2 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
=================================================================================================================
Package? ? ? ? ? ? ? ? ? ? ? Arch? ? ? ? ? ? ? ? Version? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Repository? ? ? ? Size
=================================================================================================================
Installing:
ntp? ? ? ? ? ? ? ? ? ? ? ? ? x86_64? ? ? ? ? ? ? 4.2.6p5-29.el7.centos.2? ? ? ? ? ? ? ? base? ? ? ? ? ? ? 549 k
Installing for dependencies:
autogen-libopts? ? ? ? ? ? ? x86_64? ? ? ? ? ? ? 5.18-5.el7? ? ? ? ? ? ? ? ? ? ? ? ? ? base? ? ? ? ? ? ? 66 k
ntpdate? ? ? ? ? ? ? ? ? ? ? x86_64? ? ? ? ? ? ? 4.2.6p5-29.el7.centos.2? ? ? ? ? ? ? ? base? ? ? ? ? ? ? 87 k
Transaction Summary
=================================================================================================================
Install? 1 Package (+2 Dependent packages)
Total download size: 701 k
Installed size: 1.6 M
Downloading packages:
(1/3): autogen-libopts-5.18-5.el7.x86_64.rpm? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |? 66 kB? 00:00:00? ?
(2/3): ntpdate-4.2.6p5-29.el7.centos.2.x86_64.rpm? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |? 87 kB? 00:00:00? ?
(3/3): ntp-4.2.6p5-29.el7.centos.2.x86_64.rpm? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? | 549 kB? 00:00:00? ?
-----------------------------------------------------------------------------------------------------------------
Total? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.7 MB/s | 701 kB? 00:00:00? ?
Running transaction check
Running transaction testTransaction test succeeded
Running transaction
? Installing : autogen-libopts-5.18-5.el7.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1/3
? Installing : ntpdate-4.2.6p5-29.el7.centos.2.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2/3
? Installing : ntp-4.2.6p5-29.el7.centos.2.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3/3
? Verifying? : ntpdate-4.2.6p5-29.el7.centos.2.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1/3
? Verifying? : ntp-4.2.6p5-29.el7.centos.2.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2/3
? Verifying? : autogen-libopts-5.18-5.el7.x86_64? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3/3
Installed:
? ntp.x86_64 0:4.2.6p5-29.el7.centos.2? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Dependency Installed:
? autogen-libopts.x86_64 0:5.18-5.el7? ? ? ? ? ? ? ? ? ntpdate.x86_64 0:4.2.6p5-29.el7.centos.2? ? ? ? ? ? ? ?
Complete!
[root@ntp ~]#
```
三、配置阿里云鏡像站NTP服務(wù)
配置之前，測試服務(wù)器是否能夠訪問到阿里云NTP服務(wù)器。
```
ping ntp.aliyun.com -c 5
```
修改/etc/ntp.conf配置文件。
注釋掉原來配置文件中的NTP服務(wù)器地址，添加阿里云NTP服務(wù)器地址。
[root@ntp ~]# vi /etc/ntp.conf[root@ntp ~]# 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 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 ::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 ().#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 iburstserver ntp.aliyun.com#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# Enable public key cryptography.#cryptoincludefile /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# Disable the monitoring facility to prevent amplification attacks using ntpdc# monlist command when default restrict does not include the noquery flag. See# CVE-2013-5211 for more details.# Note: Monitoring will not be disabled with the limited restriction flag.disable monitor
[root@ntp ~]#
```
四、啟動NTP服務(wù)
啟動ntp服務(wù)
```
systemctl start ntpd
```
設(shè)置ntp服務(wù)開機自啟動
```
systemctl enable ntpd
```
查看ntp服務(wù)是否正常
```
systemctl status ntpd
```
```
[root@ntp ~]# systemctl start ntpd[root@ntp ~]# systemctl enable ntpdCreated symlink from /etc/systemd/system/multi-user.target.wants/ntpd.service to /usr/lib/systemd/system/ntpd.service.
[root@ntp ~]# systemctl status ntpd● ntpd.service - Network Time Service
? Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled; vendor preset: disabled)
? Active: active (running) since Sun 2021-11-28 19:06:34 CST; 23h left
Main PID: 1988 (ntpd)
? CGroup: /system.slice/ntpd.service
? ? ? ? ? └─1988 /usr/sbin/ntpd -u ntp:ntp -g
Nov 28 19:06:34 ntp ntpd[1988]: Listen normally on 3 ens32 192.168.1.50 UDP 123
Nov 28 19:06:34 ntp ntpd[1988]: Listen normally on 4 lo ::1 UDP 123
Nov 28 19:06:34 ntp ntpd[1988]: Listen normally on 5 ens32 fe80::e4b:3ef:613c:8741 UDP 123
Nov 28 19:06:34 ntp ntpd[1988]: Listening on routing socket on fd #22 for interface updatesNov 28 19:06:34 ntp ntpd[1988]: 0.0.0.0 c016 06 restart
Nov 28 19:06:34 ntp ntpd[1988]: 0.0.0.0 c012 02 freq_set kernel 0.000 PPM
Nov 28 19:06:34 ntp ntpd[1988]: 0.0.0.0 c011 01 freq_not_set
Nov 28 19:09:51 ntp ntpd[1988]: 0.0.0.0 c61c 0c clock_step -86398.982768 s
Nov 27 19:09:52 ntp ntpd[1988]: 0.0.0.0 c614 04 freq_mode
Nov 27 19:09:53 ntp ntpd[1988]: 0.0.0.0 c618 08 no_sys_peer
[root@ntp ~]#
```
五、查看NTP源
```
ntpq -p
```
即[203.107.6.88]地址為阿里云NTP服務(wù)器的IP地址。
```
[root@ntp ~]# ntpq -p
remote refid st t when poll reach delay offset jitter
203.107.6.88 100.107.25.114 2 u 56 64 7 13.685 -0.002 0.415
```
六、查看NTP服務(wù)狀態(tài)
#輸出如下內(nèi)容，表示在同步中，需要耐心等待一下
[root@ntp ~]# ntpstatunsynchronised
? time server re-starting
? polling server every 8 s# 輸出如下內(nèi)容，表示同步成功
```
? [root@ntp ~]# ntpstatsynchronised to NTP server (203.107.6.88) at stratum 3
? time correct to within 958 ms
? polling server every 64 s
```
七、將客戶端與NTP服務(wù)器同步
```
[root@client ~]# ntpdate -d 192.168.1.5028 Nov 19:37:54 ntpdate[2880]: ntpdate 4.2.6p5@1.2349-o Tue Jun 23 15:38:19 UTC 2020 (1)
Looking for host 192.168.1.50 and service ntp
host found : 192.168.1.50
transmit(192.168.1.50)
receive(192.168.1.50)
transmit(192.168.1.50)
receive(192.168.1.50)
transmit(192.168.1.50)
receive(192.168.1.50)
transmit(192.168.1.50)
receive(192.168.1.50)
server 192.168.1.50, port 123
stratum 3, precision -25, leap 00, trust 000
refid [192.168.1.50], delay 0.02652, dispersion 0.00000
transmitted 4, in filter 4
reference time:? ? e54c9534.6f868aa9? Sat, Nov 27 2021 19:29:56.435
originate timestamp: e54c9719.4617ce7f? Sat, Nov 27 2021 19:38:01.273
transmit timestamp:? e54de898.b45bc870? Sun, Nov 28 2021 19:38:00.704
filter delay:? 0.02658? 0.02655? 0.02652? 0.02660
? ? ? ? 0.00000? 0.00000? 0.00000? 0.00000
filter offset: -86399.4 -86399.4 -86399.4 -86399.4
? ? ? ? 0.000000 0.000000 0.000000 0.000000
delay 0.02652, dispersion 0.00000
offset -86399.431479
28 Nov 19:38:00 ntpdate[2880]: step time server 192.168.1.50 offset -86399.431479 sec
[root@client ~]#
```
八、將系統(tǒng)時間同步到硬件
```
[root@client ~]# hwclock -w
[root@client ~]# dateSun Nov 28 19:39:10 CST 2021
```
【阿里云官方鏡像站：? ? https://developer.aliyun.com/mirror/?utm_content=g_1000307095? ? 】
