From 2ed3de9cc4f80670cd911536c3e40239fb0e2aa6 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sat, 11 Jul 2015 14:16:40 -0300 Subject: build-sys: warn if people don't change the default NTP servers when building systemd Also, explain the situation in the docs. Relates to #437 --- DISTRO_PORTING | 19 +++++++++++++++++++ README | 5 +++++ configure.ac | 3 ++- 3 files changed, 26 insertions(+), 1 deletion(-) diff --git a/DISTRO_PORTING b/DISTRO_PORTING index d8e9ded943..07aea865be 100644 --- a/DISTRO_PORTING +++ b/DISTRO_PORTING @@ -14,6 +14,7 @@ HOWTO: --with-kbd-loadkeys= --with-kbd-setfont= --with-tty-gid= + --with-ntp-servers= 2) Try it out. Play around (as an ordinary user) with '/usr/lib/systemd/systemd --test --system' for a test run @@ -21,6 +22,24 @@ HOWTO: print the initial transaction it would execute during boot-up. This will also inform you about ordering loops and suchlike +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: + + 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. + CONTRIBUTING UPSTREAM: We generally do no longer accept distribution-specific diff --git a/README b/README index 53220ff3f2..ba8d69326f 100644 --- a/README +++ b/README @@ -261,6 +261,11 @@ 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: ENDOCODE offers professional engineering and consulting services for systemd. Please diff --git a/configure.ac b/configure.ac index 6804e03d07..999f9f84d3 100644 --- a/configure.ac +++ b/configure.ac @@ -1009,7 +1009,8 @@ AC_ARG_WITH(ntp-servers, AS_HELP_STRING([--with-ntp-servers=NTPSERVERS], [Space-separated list of default NTP servers]), [NTP_SERVERS="$withval"], - [NTP_SERVERS="time1.google.com time2.google.com time3.google.com time4.google.com"]) + [NTP_SERVERS="time1.google.com time2.google.com time3.google.com time4.google.com" + AC_MSG_WARN([*** Using Google NTP servers. Please do not ship OSes or devices with these default settings. See DISTRO_PORTING for details!])]) AC_DEFINE_UNQUOTED(NTP_SERVERS, ["$NTP_SERVERS"], [Default NTP Servers]) AC_SUBST(NTP_SERVERS) -- cgit v1.2.3-54-g00ecf