Nesting is a way of one template encompassing one or more other templates.
As it makes sense to separate out entities on individual templates for various services, applications, etc., you may end up with quite a few templates all of which may need to be linked to quite a few hosts. To simplify the picture, it is possible to link some templates together in a single template.
The benefit of nesting is that you have to link only one template ("nest", parent template) to the host and the host will inherit all entities of the linked templates ("nested", child templates) automatically. For example, if we link templates T1 and T2 to template T3, we supplement T3 with entities from T1 and T2, and not vice versa. If we link template A to templates B and C, we supplement B and C with entities from A.
To link templates, you need to take an existing template or a new one, and then:
Thus, all entities of the parent template, as well as all entities of linked templates (such as items, triggers, graphs, etc.) will now appear in the template configuration, except for linked template screens, which will, nevertheless, be inherited by hosts.
To unlink any of the linked templates, in the same form use the Unlink or Unlink and clear buttons and click Update.
Choosing the Unlink option will simply remove the association with the linked template, while not removing all its entities (items, triggers, graphs, etc.).
Choosing the Unlink and clear option will remove both the association with the linked template and all its entities (items, triggers, graphs, etc.).