On 04/23/2017 02:11 PM, Robert Moskowitz wrote: > > > On 04/22/2017 07:43 PM, Jim Perrin wrote: >> >> On 04/21/2017 06:03 AM, Robert Moskowitz wrote: >>> Fellow armv7-without-rtc-battery users. Maybe you have already learned >>> this, but I THINK I have completed my education on this thanks to >>> Miroslav Lichvar on the Chrony list. >>> >>> There are two issues here: It takes time for chronyd to set the system >>> time. And if it fails to reach the ntp servers, well, it failed to set >>> the time. >>> >>> For the first, we need to delay some services from starting until >>> chronyd is successful. Postfix is one of them. So we need the >>> following commands: >>> >>> systemctl enable chrony-wait >>> systemctl start chrony-wait >>> sed -i '/^After=/ s/$/ time-sync.target/w /dev/stdout' >>> /usr/lib/systemd/system/postfix.service >>> >> You're not going to want to do this here. Because systemd has a concept >> of overrides, administrator modifications should go in >> /etc/systemd/system, rather than directly modifying /usr/lib/systemd/* >> files. This will keep your changes across updates. > > I did not like changing postfix.service, but I have not found how to > modify the After= instructions through /etc/systemd/system. > > Can you point me to instructions? I looked at > > /etc/systemd/system/multi-user.target.wants/postfix.service > > And the change I made to /usr/lib/systemd/system/postfix.service > carried over, and the timestamp in /etc/systemd did not change. Strange. Meanwhile, I changed the SED command to: sed -i '/^After=/ s/$/ time-sync.target/w /dev/stdout' /etc/systemd/system/*.wants/postfix.service For each .service, it seems challenging to know which *.wants directory it ends up in. The wildcard seems to work here. > > thanks > >> >>> There are some possible instances where you also want to do this to >>> httpd.service, but I have been advised on the postfix list NOT to run >>> postfix if the systemtime is earlier than the postfix build date >>> >>> $ postconf -dh mail_release_date >>> 20130622 >>> >>> Plus the postfix.service runs aliases.db which will mess up your >>> aliases.db timestamp. >>> >>> Next there is that pesky issue about what if no ntp servers reached? >>> >>> First: >>> >>> cat <<EOF>/etc/sysconfig/chronyd || exit 1 >>> OPTIONS=" -s" >>> EOF >>> >>> Since Centos7 has Chronyd 2.1.1, not 2.2, we have extra work to do in >>> chronyd.conf: >>> >>> cat <<EOF>>/etc/chrony.conf || exit 1 >>> rtcdevice /dev/doesnotexist >>> EOF >>> >>> >>> I am adding this to my basic server howto page. >>> >>> >>> _______________________________________________ >>> Arm-dev mailing list >>> Arm-dev at centos.org >>> https://lists.centos.org/mailman/listinfo/arm-dev > > _______________________________________________ > Arm-dev mailing list > Arm-dev at centos.org > https://lists.centos.org/mailman/listinfo/arm-dev >