Apache private systemd /tmp in Ubuntu 18.04

[jeroen]

In Ubuntu 18.04, apache www-data has a virtual /tmp directory which cannot be seen by other users. Therefore we cannot rename an installed directory into /usr/local/lib/opencpu/apps.

It may also affect other things:

cleanup cron script

I think that it needs to use as user www-data to work. Make sure to disable the workaround when testing.

apparmor rules

Still seem to work fine as far as I can see

[jeroen]

As explained here: https://www.philipp-wagner.com/blog/2014/04/does-tmp-have-a-split-personality

jeroen@dev:~$ systemctl show apache2 | grep PrivateTmp
PrivateTmp=yes

The workaround (in that post) to disable PrivateTmp seems to work, however it is hacky. Better would be to create the temporary dir inside the public file system namespace to begin with.

[jeroen]

Adding cleanup script with JoinsNamespaceOf=apache2.service: opencpu/opencpu-server@2f1d49b