시간을 동기화하기 위해 과거에는 ntpd 데몬을 사용했지만, 이제는 좀 더 좋은 chrony를 사용할 수 있다.
먼저 chrony 패키지를 설치한다.
[root@localhost /var/lib/php]# yum install -y chrony
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
epel/x86_64/metalink | 6.1 kB 00:00:00
* base: mirror.kakao.com
* epel: ftp.jaist.ac.jp
* extras: mirror.kakao.com
* updates: mirror.kakao.com
base | 3.6 kB 00:00:00
epel | 4.7 kB 00:00:00
extras | 2.9 kB 00:00:00
updates | 2.9 kB 00:00:00
Resolving Dependencies
--> Running transaction check
---> Package chrony.x86_64 0:3.4-1.el7 will be installed
--> Processing Dependency: libseccomp.so.2()(64bit) for package: chrony-3.4-1.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 3.4-1.el7 base 251 k
Installing for dependencies:
libseccomp x86_64 2.3.1-3.el7 base 56 k
Transaction Summary
============================================================================================================================
Install 1 Package (+1 Dependent package)
Total download size: 306 k
Installed size: 788 k
Downloading packages:
(1/2): chrony-3.4-1.el7.x86_64.rpm | 251 kB 00:00:00
(2/2): libseccomp-2.3.1-3.el7.x86_64.rpm | 56 kB 00:00:00
----------------------------------------------------------------------------------------------------------------------------
Total 2.3 MB/s | 306 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-3.4-1.el7.x86_64 2/2
Verifying : libseccomp-2.3.1-3.el7.x86_64 1/2
Verifying : chrony-3.4-1.el7.x86_64 2/2
Installed:
chrony.x86_64 0:3.4-1.el7
Dependency Installed:
libseccomp.x86_64 0:2.3.1-3.el7
Complete!
[root@localhost /var/lib/php]#
패키지는 chrony이지만, 실행 데몬 이름은 chronyd이다. 먼저 상태를 보면, 아직 실행 중은 아니다.
[root@localhost /var/lib/php]# systemctl status chronyd
● chronyd.service - NTP client/server
Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:chronyd(8)
man:chrony.conf(5)chronyd를 실행후 확인
[root@localhost /var/lib/php]# systemctl start chronyd
[root@localhost /var/lib/php]# systemctl status chronyd
● chronyd.service - NTP client/server
Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2020-04-26 18:25:26 KST; 2s ago
Docs: man:chronyd(8)
man:chrony.conf(5)
Process: 11852 ExecStartPost=/usr/libexec/chrony-helper update-daemon (code=exited, status=0/SUCCESS)
Process: 11848 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, status=0/SUCCESS)
Main PID: 11850 (chronyd)
CGroup: /system.slice/chronyd.service
└─11850 /usr/sbin/chronyd
Apr 26 18:25:26 localhost.localdomain systemd[1]: Starting NTP client/server...
Apr 26 18:25:26 localhost.localdomain chronyd[11850]: chronyd version 3.4 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIV...BUG)
Apr 26 18:25:26 localhost.localdomain systemd[1]: Started NTP client/server.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost /var/lib/php]# 부팅 이후에도 실행되도록 설정한다. timedatectl 커맨드로 시간 정보를 확인하고, NTP 동기되어 있는지 확인한다.
[root@localhost /var/lib/php]# systemctl enable chronyd
[root@localhost /var/lib/php]# timedatectl
Local time: Sun 2020-04-26 18:26:13 KST
Universal time: Sun 2020-04-26 09:26:13 UTC
RTC time: Sun 2020-04-26 18:26:13
Time zone: Asia/Seoul (KST, +0900)
NTP enabled: yes
NTP synchronized: yes
RTC in local TZ: no
DST active: n/a
[root@localhost /var/lib/php]#
[root@localhost /var/lib/php]# timedatectl | grep "NTP synchronized"
NTP synchronized: yes
[root@localhost /var/lib/php]#만약 NTP synchronized: no라면 다음 명령어를 사용한다.
$ sudo timedatectl set-ntp yes
chrony가 시간 동기화를 제대로 진행하고 있는지 확인한다.
[root@localhost /var/lib/php]# chronyc tracking
Reference ID : 0DD15432 (ec2-13-209-84-50.ap-northeast-2.compute.amazonaws)
Stratum : 3
Ref time (UTC) : Sun Apr 26 09:30:59 2020
System time : 0.000062582 seconds slow of NTP time
Last offset : -0.000211937 seconds
RMS offset : 0.000590429 seconds
Frequency : 7.488 ppm slow
Residual freq : -0.083 ppm
Skew : 3.242 ppm
Root delay : 0.004435404 seconds
Root dispersion : 0.000844962 seconds
Update interval : 65.2 seconds
Leap status : Normal
[root@localhost /var/lib/php]#
chrony가 동기화에 사용되는 네트워크를 확인한다.
[root@localhost /var/lib/php]# chronyc sources
210 Number of sources = 4
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^- 106.247.248.106 2 6 377 24 +498us[ +519us] +/- 28ms
^- dadns.cdnetworks.co.kr 2 6 377 23 +2238us[+2259us] +/- 49ms
^- send.mx.cdnetworks.com 2 6 377 24 -596us[ -575us] +/- 75ms
^* ec2-13-209-84-50.ap-nort> 2 6 377 22 +52us[ +73us] +/- 3287us
[root@localhost /var/lib/php]#
출처: https://knight76.tistory.com/entry/centos7-시간-동기화-하기-chrony [김용환 블로그(2004-2020)]
http://gosu250.blog.me/221119593871
NTP 가동/중지/확인
* ntp 패키지 설치#yum install ntp 1. NTP 상태 확인(서비스가 시작되어 있어야 조회됨)[root@UCS-...
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