Docker – Wrong time on Docker debian container despite NTP

dockerntp

I am creating a simple debian-based docker (php:7-apache). To create it I use:

docker run -d -p 80:80 --name myname -v "$PWD":/var/www/html php:7-apache

I noticed that my docker is possibly suffering from this issue, therefore now, each time I run the container, I also run:

docker run -it --rm --privileged --pid=host php:7-apache nsenter -t 1 -m -u -n -i date -u $(date -u +%m%d%H%M%Y)

This fixed my issue. The clock is now ok. However, before trying this, I simply tried to install ntp on the docker and set it up:

# apt-get install ntp
# vi /etc/ntp.conf # commented pools and added these servers http://www.pool.ntp.org/zone/europe
# /etc/init.d/ntp start
# /usr/bin/ntpq -p    
remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
v.bsod.fr       193.190.230.66   2 u   24   64    1   32.924  -117284   0.004
tomia.ordimatic 62.210.36.58     3 u   23   64    1   26.158  -117286   0.004
pacifica.ufp.ne 162.23.41.10     2 u   25   64    1   27.922  -117281   0.004
aquila.init7.ne 189.247.1.117    2 u   24   64    1   34.736  -117291   0.004

# date
...WRONG DATE!!!

So, why isn't ntp working?
I would assume it's better to get NTP to work so that if drifts occur they are correct automatically, instead of setting by hand once the clock from my host system.

Thanks

EDIT: Second Try

apt-get install ntp 

# setting time
sed 's/pool /#pool /g' /etc/ntp.conf > /tmp/ntp.conf.tmp
echo "server 0.europe.pool.ntp.org" >> /tmp/ntp.conf.tmp
echo "server 1.europe.pool.ntp.org" >> /tmp/ntp.conf.tmp
echo "server 2.europe.pool.ntp.org" >> /tmp/ntp.conf.tmp
echo "server 3.europe.pool.ntp.org" >> /tmp/ntp.conf.tmp
mv /tmp/ntp.conf.tmp /etc/ntp.conf
ntpd -qxg | grep "ntpd:"
/etc/init.d/ntp start
echo "Date on ws container: `date` - correct: `(curl time.correct.com?iso)2>/dev/null`"

Gives me:

13 Apr 11:40:47 ntpd[922]: ntpd: time slew +14.502687 s
ntpd: time slew +14.502687s
[ ok ] Starting NTP server: ntpd.
Date on ws container: Fri Apr 13 11:40:47 UTC 2018 - correct: 2018-04-13T11:41:02Z

So, despite trying to set the time manually with ntpd (ntpdate is deprecated as per http://doc.ntp.org/4.1.0/ntpd.htm), and do getting that I'm 14 seconds behind, the container doesn't get the time set. Any idea on my mistake?
The script above is run with a docker exec (with or without –privilege doesn't make a difference).

The full output of ntpd -qxg is as follows:

13 Apr 12:52:43 ntpd[922]: ntpd 4.2.8p10@1.3728-o Sun Feb 25 21:22:55 UTC 2018 (1): Starting
13 Apr 12:52:43 ntpd[922]: Command line: ntpd -qxg
13 Apr 12:52:43 ntpd[922]: proto: precision = 3.398 usec (-18)
13 Apr 12:52:43 ntpd[922]: Listen and drop on 0 v6wildcard [::]:123
13 Apr 12:52:43 ntpd[922]: Listen and drop on 1 v4wildcard 0.0.0.0:123
13 Apr 12:52:43 ntpd[922]: Listen normally on 2 lo 127.0.0.1:123
13 Apr 12:52:43 ntpd[922]: Listen normally on 3 eth0 172.17.0.3:123
13 Apr 12:52:43 ntpd[922]: Listening on routing socket on fd #21 for interface updates
13 Apr 12:52:50 ntpd[922]: ntpd: time slew -2.923397 s
ntpd: time slew -2.923397s

EDIT2: Found solution!

Solution follows. The answer by @kubanczyk is correct, but in the specifics of Docker we need to super-power the manual time update:

# apt-get install ntp
# nsenter -t 1 -m -u -n -i ntpd -qxg
# /etc/init.d/ntp start

Best Answer

The ntpq offset is in milliseconds, for example offset -117291 translates to about 117 seconds difference.

The UDP connectivity is correct. If it wasn't, you wouldn't get an offset.

The ntpd conservatively refuses to set the clock. Generally, it only works by slowing/speeding the clock slightly. (And when the time offset is larger than 1000 seconds, it ignores the source completely).

You need to stop ntpd and run ntpdate to set your clock. Now start ntpd back up. The offset would be smaller, so it will synchronize much faster. The time is precisely synchronized when ntpq displays a * like this:

# ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*10.0.21.44      10.0.21.1        6 u  370 1024  377    1.570   -0.926   6.177
+10.0.21.46      10.0.21.1        6 u  246 1024  377    2.616    2.904   6.750
-10.0.21.45      192.168.1.1      6 u  391 1024  377    1.620   13.230   9.495
+10.0.21.47      192.168.1.1      6 u  327 1024  377    2.463    2.994  11.56
-10.0.192.50     10.0.21.44       7 u  213 1024  377    0.357   -5.926  11.969
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