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authorLennart Poettering <lennart@poettering.net>2015-07-11 14:16:40 -0300
committerLennart Poettering <lennart@poettering.net>2015-07-11 14:24:29 -0300
commit2ed3de9cc4f80670cd911536c3e40239fb0e2aa6 (patch)
tree13e52c42ed399df184cf22613c1a4ff1bc60a3de
parent43694a8cc70667498f3ffc5d9325b7d0428558e5 (diff)
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
-rw-r--r--DISTRO_PORTING19
-rw-r--r--README5
-rw-r--r--configure.ac3
3 files changed, 26 insertions, 1 deletions
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 <https://endocode.com/> 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)