[mythtv-users] anacron time change after upgrade to Ubuntu 18.04

[Stephen Worthington]

On Tue, 6 Nov 2018 09:39:12 -0500, you wrote:

>
>On 11/6/18 7:46 AM, Stephen Worthington wrote:
>> On Tue, 6 Nov 2018 06:59:31 -0500, you wrote:
>>
>>> On my backend I have 2 cron jobs I put into /etc/cron.daily for database
>>> backup and optimization. The scripts email when done with the date and time.
>>>
>>> On Ubuntu 16.04 it ran around 7:35 am. After the 'do-release-upgrade' it
>>> runs at 12:10 am.
>>>
>>> I always wondered why 7:35am with a /etc/crontab entry like the one
>>> below, but I really can't figure out 12:10 am based on it.
>>>
>>> Any ideas?
>>>
>>> 25 6    * * *    root    test -x /usr/sbin/anacron || ( cd / &&
>>> run-parts --report /etc/cron.daily )
>>>
>>> Jim A
>> If you read that crontab code carefully, you will see that what it is
>> doing is testing to see if an anacron executable is present, and if
>> so, it does not run the cron.daily tasks from crontab.  As Ubuntu does
>> have an anacron executable present, those crontab entries do nothing,
>> and it is left to anacron to run the /etc/cron.daily, /etc/cron.weekly
>> and /etc/cron.monthly tasks.  The /etc/cron.hourly tasks, however are
>> run from crontab.
>>
>> In Ubuntu 18.04, anacron is now run from systemd.  There are two
>> systemd units:
>>
>> /lib/systemd/system/anacron.service
>> /lib/systemd/system/anacron.timer
>>
>> The main unit that actually runs anacron is anacron.service.  The
>> anacron.service unit is run when the PC starts up (as long as mains
>> power is available) and when it wakes up from a sleep mode.  The
>> anacron.timer unit runs anacron.service every hour, and
>> anacron.service runs anacron.  Here is what is in those two unit
>> files:
>>
>> root at mypvr:/lib/systemd/system# cat anacron.service
>> [Unit]
>> Description=Run anacron jobs
>> After=time-sync.target
>> ConditionACPower=true
>> Documentation=man:anacron man:anacrontab
>>
>> [Service]
>> ExecStart=/usr/sbin/anacron -dsq
>> IgnoreSIGPIPE=false
>>
>> [Install]
>> WantedBy=multi-user.target
>> root at mypvr:/lib/systemd/system# cat anacron.timer
>> [Unit]
>> Description=Trigger anacron every hour
>>
>> [Timer]
>> OnCalendar=hourly
>> RandomizedDelaySec=5m
>> Persistent=true
>>
>> [Install]
>> WantedBy=timers.target
>>
>> So in 18.04, you will get the cron.{daily,weekly,monthly} jobs being
>> run about 5 minutes after the PC starts up, and after that at about 5
>> past midnight.  The 5 minutes bit is because after anacron it started,
>> it wait 5 minutes before it does anything.  That is very useful as it
>> allows you to kill the anacron task immediately after you reboot your
>> MythTV box, so it will then run anacron at the usual time instead of
>> immediately.  You only need to kill anacron if the day has changed
>> since anacron was last run, as anacron uses timestamps stored in files
>> in /var/spool/anacron to tell it when its jobs were last run and will
>> not run them again on the same day (or week or month).  The time that
>> anacron gets run at has a variable extra delay of up to 5 minutes
>> because of the "RandomizedDelaySec=5m" line in anacron.timer.  So
>> anacron will run its tasks 5 minutes after boot, and 5-10 minutes
>> after the hour after the day changes ie 5-10 minutes after midnight.
>>
>> In earlier Ubuntu versions, before anacron was run from systemd, it
>> was run from cron using the file /etc/cron.d/anacron.  That started
>> anacron at 07:30.  Now, the /etc/cron.d/anacron file will only run
>> anacron if systemd is not being used.
>>
>> I found the change in timing from 07:30 to midnight to be a big
>> problem.  I have a huge database, and my backup and database check
>> jobs take over half an hour, during which mythfrontend is not very
>> usable for long periods.  And if I have more than one recording
>> happening, I can get bad recordings.  Since I often have multiple
>> recordings happening at midnight, and I am also likely to be watching
>> a programme, it was very annoying to have anacron running then.  So I
>> have changed anacron back to being run at 07:30 only.  I consider that
>> anacron being run every hour is actually a bug - it does not run the
>> cron.hourly jobs, so it only needs to be run once a day.
>>
>> To change it back to how it used to be, I created a systemd override
>> file for anacron.timer:
>>
>> root at mypvr:/etc/systemd/system# ll -d ana*
>> drwxr-xr-x 2 root root 4096 Oct 21 01:13 anacron.timer.d/
>> root at mypvr:/etc/systemd/system# cd anacron.timer.d/
>> root at mypvr:/etc/systemd/system/anacron.timer.d# ll
>> total 12
>> drwxr-xr-x  2 root root 4096 Oct 21 01:13 ./
>> drwxr-xr-x 27 root root 4096 Oct 23 23:45 ../
>> -rw-r--r--  1 root root  166 Oct 21 01:13 anacron-timer-override.conf
>> root at mypvr:/etc/systemd/system/anacron.timer.d# cat
>> anacron-timer-override.conf
>> [Unit]
>> Description=Trigger anacron at 07:30, as happened before the Ubuntu
>> 18.04 upgrade.
>>
>> [Timer]
>> OnCalendar=
>> OnCalendar=07:30
>> RandomizedDelaySec=0s
>> Persistent=true
>>
>> If you want to create an override file like mine, the easy way is to
>> do this command:
>>
>> sudo systemctl edit anacron.timer
>>
>> and paste my override file into it.  The systemctl edit command is
>> only available in newer versions of systemd, but it is very useful as
>> it sets up the override directory and .conf file with the right
>> ownership and permissions automatically.
>>
>> I have filed a bug report about this problem, but I have not had any
>> response to it yet:
>>
>> https://bugs.launchpad.net/ubuntu/+source/anacron/+bug/1799361
>
>
>This is a great explanation and very helpful.  I've duplicated what you 
>did and will look for the changes to take affect tomorrow.
>
>Thanks,
>
>Jim A

You can check to see what is going to happen by using:

sudo systemctl status anacron.timer
sudo systemctl status anacron