It's now ok to use Google NTP servers (#5311)

This commit is contained in:
Michael Shields 2017-02-11 21:30:40 -08:00 committed by Zbigniew Jędrzejewski-Szmek
parent dbb1d5cf69
commit 501bf2d5d2
3 changed files with 12 additions and 22 deletions

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@ -25,22 +25,20 @@ HOWTO:
NTP POOL:
By default, timesyncd uses the Google NTP servers
time[1-4].google.com. They serve time that is not standards
compliant, and can be up to .5s off. Google does not
officially support these servers for the broader
audience. Distributions and vendors really should not ship
OSes or devices with these NTP servers configured. Instead,
please register your own vendor pool at ntp.org and make it
the built-in default by passing --with-ntp-servers= to
configure. Registering vendor pools is free:
By default, timesyncd uses the Google Public NTP servers
time[1-4].google.com. They serve time that uses a leap second
smear, and can be up to .5s off from servers that use stepped
leap seconds.
https://developers.google.com/time/smear
If you prefer to use leap second steps, please register your own
vendor pool at ntp.org and make it the built-in default by
passing --with-ntp-servers= to configure. Registering vendor
pools is free:
http://www.pool.ntp.org/en/vendors.html
Again, if you ship your software or device with the default
NTP servers, then you will get served wrong time, and will
rely on services that might not be supported for long.
PAM:
The default PAM config shipped by systemd is really bare bones.
It does not include many modules your distro might want to enable

5
README
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@ -275,11 +275,6 @@ WARNINGS:
false positives will be triggered by code which violates
some rules but is actually safe.
Currently, systemd-timesyncd defaults to use the Google NTP
servers if not specified otherwise at configure time. You
really should not ship an OS or device with this default
setting. See DISTRO_PORTING for details.
ENGINEERING AND CONSULTING SERVICES:
Kinvolk (https://kinvolk.io) offers professional engineering
and consulting services for systemd. Please contact Chris Kühl

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@ -1146,10 +1146,7 @@ AC_ARG_WITH(ntp-servers,
AS_HELP_STRING([--with-ntp-servers=NTPSERVERS],
[space-separated list of default NTP servers]),
[NTP_SERVERS="$withval"],
[NTP_SERVERS="time1.google.com time2.google.com time3.google.com time4.google.com"
AC_MSG_WARN([*** Using Google NTP servers.
Do not ship OSes or devices with these default settings.
See DISTRO_PORTING for details!])])
[NTP_SERVERS="time1.google.com time2.google.com time3.google.com time4.google.com"])
AC_DEFINE_UNQUOTED(NTP_SERVERS, ["$NTP_SERVERS"], [Default NTP Servers])
AC_SUBST(NTP_SERVERS)