anacron (e.g., cron.daily) not working after upgrade to 15.04

[Adam Funk]

Hi,

Yesterday I upgraded two machines to 15.04, & this morning both of
them have failed to run /etc/cron.daily jobs with this error e-mail:

Subject: Cron <root at bunsen>   start -q anacron || :

start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused

AFAICT from googling the error message, this seems to be caused by the
switch from upstart to systemd, but I'm not sure how to fix it.  I see
here [1] that it's possible just to switch back to upstart, but I
wonder if that's a bad idea in the long term.  Otherwise, how do I get
anacron working again?

Thanks,
Adam


[1] 
<https://wiki.ubuntu.com/SystemdForUpstartUsers#Permanent_switch_back_to_upstart>