ヘルプ:NTPサーバー構築(chrony)(AlmaLinux9)

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Chrony をインストールして、時刻同期サービスを提供する NTP サーバーを構築します。

chrony のインストール

[root@host2 ~]# dnf -y install chrony

chrony サーバー設定

[root@host2 ~]# vi /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
#Please consider joining the pool (http://www.pool.ntp.org/join.html).
# 同期をとるサーバーを変更
#pool 2.centos.pool.ntp.org iburst
pool ntp.nict.jp iburst

# Allow NTP client access from local network.
# 内部からの時刻同期を許可
#allow 192.168.0.0/16
allow 192.168.1.0/24

chronyd の起動

[root@host2 ~]# systemctl enable --now chronyd

動作確認

[root@host2 ~]# systemctl status chronyd
● chronyd.service - NTP client/server
   Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; preset: enabled)
   Active: active (running) since Sat 2024-04-06 16:15:54 JST; 20h ago
      Docs: man:chronyd(8)
             man:chrony.conf(5)
   Main PID: 937 (chronyd)
      Tasks: 1 (limit: 48236)
     Memory: 3.0M
        CPU: 157ms
     CGroup: /system.slice/chronyd.service
             mq937 /usr/sbin/chronyd -F 2

 4月 06 16:15:53 host2.awajp.com systemd[1]: Starting NTP client/server...
 4月 06 16:15:54 host2.awajp.com chronyd[937]: chronyd version 4.3 starting (+CMDMON +NTP +>
 4月 06 16:15:54 host2.awajp.com chronyd[937]: Using right/UTC timezone to obtain leap seco>
 4月 06 16:15:54 host2.awajp.com chronyd[937]: Loaded seccomp filter (level 2)
 4月 06 16:15:54 host2.awajp.com systemd[1]: Started NTP client/server.
 4月 06 16:16:03 host2.awajp.com chronyd[937]: Selected source 202.182.111.234 (2.almalinux>
 4月 06 16:16:03 host2.awajp.com chronyd[937]: System clock TAI offset set to 37 seconds
 4月 06 16:16:05 host2.awajp.com chronyd[937]: Selected source 122.215.240.51 (2.almalinux.>
 4月 06 16:16:06 host2.awajp.com chronyd[937]: Selected source 2001:a7ff:102::a

時刻同期状態確認

[root@host2 ~]# chronyc sources -v

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current best, '+' = combined, '-' = not combined,
| /             'x' = may be in error, '~' = too variable, '?' = unusable.
||                                                 .- 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
===============================================================================
^- time.cloudflare.com           3  10   377   689  +2279us[+2213us] +/-   68ms
^- 122x215x240x51.ap122.ftt>     2  10   377   702  +1085us[+1020us] +/-   38ms
^- 202.182.111.234.vultruse>     2  10   377   141   -629us[ -629us] +/-   14ms
^+ wasabi.ruselabs.com           2  10   377  1014   -607us[ -662us] +/- 9380us
^* 2001:a7ff:102::a              1   9   377   355   +864us[ +787us] +/- 6234us
^+ 2001:a7ff:102::b              1  10   377   713  +1195us[+1130us] +/- 6314us

[root@host2 ~]# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^- time.cloudflare.com           3  10   377   768  +2279us[+2213us] +/-   68ms
^- 122x215x240x51.ap122.ftt>     2  10   377   781  +1085us[+1020us] +/-   38ms
^- 202.182.111.234.vultruse>     2  10   377   220   -629us[ -629us] +/-   14ms
^+ wasabi.ruselabs.com           2  10   377    63   -551us[ -551us] +/- 9555us
^* 2001:a7ff:102::a              1   9   377   435   +864us[ +787us] +/- 6234us
^+ 2001:a7ff:102::b              1  10   377   793  +1195us[+1130us] +/- 6314us