ntpd 没有更新正确的时间

Question

尝试将我的 Ubuntu 服务器配置为与 pool.ntp.org 同步。遵循本指南https://help.ubuntu.com/community/UbuntuTime。

我已经将我的 ntp.conf 配置如下

cat /etc/ntp.conf
# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift


# Enable this if you want statistics to be logged.
statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable


# You do need to talk to an NTP server or two (or three).
server 0.north-america.pool.ntp.org
server 1.north-america.pool.ntp.org
server 2.north-america.pool.ntp.org
server 3.north-america.pool.ntp.org


# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1

# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust


# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 192.168.123.255

# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines.  Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient

然后我把系统更新到很远

date -s "2 OCT 2006 18:00:00"

并尝试重新启动ntpd，时间仍然是2006年。

ntpq --peers; date
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 dev1-c.sje007.i 209.81.9.7       2 b   48   64  177   80.623  1205991 1100914
 ox.eicat.ca     139.78.135.14    2 b   18   64  377   24.743  1205991 1019249
 ntp1.Housing.Be 169.229.128.214  3 b   62   64  177   94.714   -5.160 6962796
 ns1.your-site.c 10.1.5.2         3 b   26   64  177   10.913   -9.521 6962796
Mon Oct  2 18:02:29 UTC 2006

为什么ntp不表现？

Answer 1

在本地时间和池时间之间存在一定差异以上时，ntp 将“回转”更新，即始终执行很少的更改。这是为了让您的系统行为不会完全跳出块。以下是手册页的摘录：

 -x 通常情况下，如果偏移量小于步长阈值（默认为 128 毫秒），则时间将被转换，如果高于阈值则为步长。
              此选项将阈值设置为 600 秒，这正好在手动设置时钟的精度窗口内。注：由于压摆率
              典型的 Unix 内核限制为 0.5 ms/s，每一秒的调整需要 2000 s 的摊销间隔。因此，调整为
              多达 600 秒将需要近 14 天才能完成。此选项可与 -g 和 -q 选项一起使用。注意：内核时间纪律
              使用此选项禁用。

根据您当前的时差，您需要很长时间才能赶上。我建议您手动更改为较小的差异，然后观察这是否有效。