CentOS 7 で NTP クライアントを設定するには、CentOS 7 では chronyd を使うようです。
cronyd
# yum -y install chrony
# vi /etc/chrony.conf
: 以下の通り変更（サーバーの変更）
# 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 iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
server ntp.nict.jp iburst
server 0.jp.pool.ntp.org iburst
server 1.jp.pool.ntp.org iburst
:
# systemctl start chronyd.service
# systemctl enable chronyd.service
# systemctl status chronyd.service
chronyd.service - NTP client/server
Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)
Active: active (running) since 日 2015-03-29 14:47:46 JST; 8min ago
Main PID: 9930 (chronyd)
CGroup: /system.slice/chronyd.service
└─9930 /usr/sbin/chronyd -u chrony
:
確認は、
# chronyc sources -v
210 Number of sources = 3
.-- 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
|| / xxxx = adjusted offset,
|| Log2(Polling interval) -. | yyyy = measured offset,
|| \ | zzzz = estimated error.
|| | |
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^* ntp-b2.nict.go.jp 1 7 377 37 +3279ns[+5000ns] +/- 930us
^- secure.opticnerve.asia 2 7 377 106 -9930us[-9926us] +/- 98ms
^- x.ns.gin.ntt.net 2 6 377 37 -557us[ -555us] +/- 65ms
# chronyc tracking
Reference ID : 133.243.238.163 (ntp-b2.nict.go.jp)
Stratum : 2
Ref time (UTC) : Sun Mar 29 06:00:51 2015
System time : 0.000000760 seconds fast of NTP time
Last offset : 0.000001721 seconds
RMS offset : 0.000107525 seconds
Frequency : 0.071 ppm fast
Residual freq : 0.001 ppm
Skew : 0.130 ppm
Root delay : 0.001857 seconds
Root dispersion : 0.000132 seconds
Update interval : 65.1 seconds
Leap status : Normal
#
ntpd
chronyd を使用しない場合には ntpd も使用できます。
# yum -y install ntp
# vi /etc/ntp.conf
: 以下の通り変更
# 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 iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
server ntp.nict.jp
:
# systemctl start ntpd.service
# systemctl enable ntpd.service
ln -s '/usr/lib/systemd/system/ntpd.service' '/etc/systemd/system/multi-user.target.wants/ntpd.service'
# systemctl status ntpd.service
ntpd.service - Network Time Service
Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled)
Active: active (running) since 土 2015-03-28 01:20:52 JST; 30s ago
Main PID: 5816 (ntpd)
CGroup: /system.slice/ntpd.service
└─5816 /usr/sbin/ntpd -u ntp:ntp -g
:
# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*ntp-b3.nict.go. .NICT. 1 u 52 64 3 1.948 -0.060 0.008
#
確認バージョン
# cat /etc/redhat-release
CentOS Linux release 7.0.1406 (Core)
# uname -srvo
Linux 3.10.0-123.el7.x86_64 #1 SMP Mon Jun 30 12:09:22 UTC 2014 GNU/Linux