From Coren:

Hello maintainers,

If your project currently has instances still running Ubuntu Precise,
they will need to be rebooted at some point early next week to finish
applying

https://phabricator.wikimedia.org/T95555

While we will plan a general reboot of all instances still using idmap
in the short term, you may all reboot the instances yourselves at any
point before that when it is convenient/reasonable to do so.

Rebooting the instances will finish disabling idmap on them, which means
that they will not need to be restarted next week. Please note that
*only* instances running Precise need to be rebooted - if they were
imaged with Ubuntu Trusty or Debian Jessie, there is no intervention to
make and they will not be rebooted.
~ Marc

Servers to reboot:

• wikimetrics staging

(re-assigned to Marcel because he did all the work on this. However, we ended up not rebooting some of the instances and they were mostly fine).