如何設定時區與NTP服務在RHEL7/CentOS7
如何設定時區與 NTP 服務在 RHEL7/CentOS7 chrony 包含兩個程序，chronyd 是一個可以在啟動時啟動的守護進程，chronyc 是一個命令行界面程序，可用於監控 chronyd 的性能並在運行時更改各種運行參數。
注意 ntpd 和 chronyd 擇一就可，不要同時運作。
設定時區 ~# timedatectl set-timezone Asia/Taipei ~# timedatectl Local time: Tue 2018-03-27 14:13:38 CST Universal time: Tue 2018-03-27 06:13:38 UTC RTC time: Tue 2018-03-27 06:13:40 Time zone: Asia/Taipei (CST, +0800) NTP enabled: no NTP synchronized: no RTC in local TZ: no DST active: n/a 設定 chronyd # 安裝 ~# yum install -y chrony # 配置設定檔 ~# cat /etc/chrony.conf # Use public servers from the pool.ntp.org project. # Please consider joining the pool (http://www.pool.ntp.org/join.html). server 0.tw.pool.ntp.org iburst --->改成本地的伺服器 server 1.tw.pool.ntp.org iburst --->改成本地的伺服器 server 2.tw.pool.ntp.org iburst --->改成本地的伺服器 server 3.tw.pool.ntp.org iburst --->改成本地的伺服器 # 啟動服務和設為開機時啟動 ~# systemctl enable chronyd ~# systemctl start chronyd racking 參數顯示有關系統時間效能 ~# chronyc tracking Reference ID : 3DD8996B (61-216-153-107.hinet-ip.hinet.net) --->表示現在同步的時間伺服器，如果沒有id表示沒有同步 Stratum : 4 --->表示計算機有多少"跳hop" 表示本地的是第四層 Ref time (UTC) : Tue Mar 27 06:03:38 2018 --->最後一次測量的時間 System time : 0.000040356 seconds fast of NTP time --->調整系統時間 Last offset : +0.000163738 seconds RMS offset : 0.000163738 seconds Frequency : 21.384 ppm fast Residual freq : +0.000 ppm Skew : 675.319 ppm Root delay : 0.008527911 seconds Root dispersion : 0.066466033 seconds Update interval : 2.0 seconds Leap status : Normal --->Normal要顯示此值, Insert second, Delete second or Not synchronised. ~# chronyc sources -v 210 Number of sources = 4 .-- 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 =============================================================================== ^* 59-124-29-241.hinet-ip.h> 3 6 37 24 -1462us[-2363us] +/- 49ms ^+ 61-216-153-107.hinet-ip.> 3 6 37 23 -556us[ -556us] +/- 64ms ^? 59-125-122-217.hinet-ip.> 0 7 0 - +0ns[ +0ns] +/- 0ns ^- 61-216-153-105.hinet-ip.> 3 6 37 23 -280us[ -280us] +/- 64ms 看同步源頭的資訊 ~# chronyc sourcestats -v 210 Number of sources = 4 .- Number of sample points in measurement set. / .- Number of residual runs with same sign. | / .- Length of measurement set (time). | | / .- Est. clock freq error (ppm). | | | / .- Est. error in freq. | | | | / .- Est. offset. | | | | | | On the -. | | | | | | samples. \ | | | | | | | Name/IP Address NP NR Span Frequency Freq Skew Offset Std Dev ============================================================================== 59-124-29-241.hinet-ip.h> 6 5 135 -0.454 4.553 -784us 66us 61-216-153-107.hinet-ip.> 6 6 135 +4.455 19.761 +622us 247us 59-125-122-217.hinet-ip.> 0 0 0 +0.000 2000.000 +0ns 4000ms 61-216-153-105.hinet-ip.> 6 4 136 +8.965 42.440 +1250us 495us 將系統時間寫到硬體(主機板上的時間)上 ~# hwclock --systohc ~# date ; hwclock Tue Mar 27 14:07:57 CST 2018 Tue 27 Mar 2018 02:07:58 PM CST -0.938012 seconds
