In Ansible 2.2, the include_role directive came into existence as
a Tech Preview. It is still a Tech Preview through Ansible 2.4
(and in current devel branch), but with a noteable change. The
default behavior switched from static: true to static: false
because that functionality moved to the newly introduced
import_role directive (in order to stay consistent with include*
being dynamic in nature and `import* being static in nature).
The dynamic include is considerably more memory intensive as it will
dynamically create a role import for every host in the inventory
list to be used. (Also worth noting, there is at the time of this
writing an object allocation inefficiency in the dynamic include
that can in certain situations amplify this effect considerably)
This change is meant to mitigate the pressure on memory for the
Ansible control host.
We need to evaluate where it makes sense to dynamically include roles
and revert back to dynamic inclusion if and where it makes sense to do
so.