[Arm-dev] Customizing Chronyd for no battery

[Robert Moskowitz]

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
>