Here is our simple tip for your healthy server’s date and time:

Immediately synchronize the clock of your computer when using the openntpd (a lightweight version of ntpd with client-only mode).

Use the “-s” (lower “s” letter) to instruct the daemon ntpd to synchronize the clock immediately after it discovers a healthy time server!

-s          Try to set the time immediately at startup, as opposed to slowly adjusting the clock.  ntpd will stay in the foreground for up to 15 seconds waiting
                 for one of the configured NTP servers to reply.

Find the start-up configuration file in your “/etc” (for your Linux distribution, its name is probably ntpd, for Gentoo it is “/etc/conf.d/ntpd”, the thing is to find the start-up confiuration script, not the ntpd.conf, which is the ntpd configuration file for the daemon) and include “-s” in the NTPD_OPTS:

cat /etc/conf.d/ntpd 
# /etc/conf.d/ntpd: config file for openntpd's ntpd

NTPD_OPTS="-s"

Restart the service.

If you use it in a virtualized environment like containers (docker, lxc, lxd and so on) and qemu, virtualbox, vmware and so on and you often suspend the machine to synchronize the clock when you resume it you must manually restart the openntpd service!!! Or you are going to wait for slowly adjusting the time as usual.

Information status

There is a utility to check what’s going on with the openntpd – ntpctl. It has only three read-only commands:

usage: ntpctl -s all | peers | Sensors | status

Here is the output of “all” option (you should be root):

local ~ # ntpctl -s all
16/20 peers valid, clock synced, stratum 2

peer
   wt tl st  next  poll          offset       delay      jitter
77.70.121.24 from pool 0.gentoo.pool.ntp.org
    1 10  2   14s   32s        -0.512ms     5.184ms     0.287ms
195.238.84.23 from pool 0.gentoo.pool.ntp.org
    1 10  3   18s   30s         0.033ms     1.880ms     0.548ms
46.40.123.212 from pool 0.gentoo.pool.ntp.org
    1 10  2    9s   32s        -1.635ms     8.085ms     0.070ms
185.117.82.71 from pool 0.gentoo.pool.ntp.org
    1 10  2   14s   30s         2.922ms     3.936ms     0.279ms
78.128.99.30 from pool 1.gentoo.pool.ntp.org
    1 10  2   12s   34s         0.979ms     3.447ms     0.239ms
212.70.148.13 from pool 1.gentoo.pool.ntp.org
    1 10  2   11s   33s        -0.339ms     5.087ms     0.290ms
84.43.191.2 from pool 1.gentoo.pool.ntp.org
    1 10  2   14s   31s         1.658ms    13.987ms     0.229ms
195.85.215.215 from pool 1.gentoo.pool.ntp.org
    1 10  2   21s   34s        -0.442ms     3.770ms     0.366ms
2a0b:f800:0:1::101 from pool 2.gentoo.pool.ntp.org
    1  2  -    6s   15s             ---- peer not valid ----
2001:67c:20d0:c0::acad:123 from pool 2.gentoo.pool.ntp.org
    1  2  -    6s   15s             ---- peer not valid ----
2a02:6800:0:99::2 from pool 2.gentoo.pool.ntp.org
    1  2  -    6s   15s             ---- peer not valid ----
2001:67c:21bc:1e::1:123 from pool 2.gentoo.pool.ntp.org
    1  2  -    6s   15s             ---- peer not valid ----
93.123.39.67 from pool 2.gentoo.pool.ntp.org
    1 10  1   11s   31s         0.169ms     4.216ms     0.156ms
195.85.215.8 from pool 2.gentoo.pool.ntp.org
 *  1 10  1    0s   32s        -0.456ms     3.898ms     0.256ms
212.70.148.11 from pool 2.gentoo.pool.ntp.org
    1 10  3    3s   33s         1.667ms     3.976ms     0.246ms
185.117.82.70 from pool 2.gentoo.pool.ntp.org
    1 10  2   16s   30s         5.331ms     3.789ms     0.225ms
87.97.157.120 from pool 3.gentoo.pool.ntp.org
    1 10  3    4s   34s        -2.058ms    14.554ms     0.374ms
185.117.82.66 from pool 3.gentoo.pool.ntp.org
    1 10  2    3s   32s        -1.497ms     3.726ms     0.233ms
85.11.185.61 from pool 3.gentoo.pool.ntp.org
    1 10  3    0s   34s        -5.923ms     4.309ms     0.905ms
84.54.128.102 from pool 3.gentoo.pool.ntp.org
    1 10  2    2s   33s        -2.942ms    11.703ms     0.345ms