ansible collections with host_vars

Question

Is there a way to use the host_vars/ or group vars/ OR for that matter defaults/ or any sort of variable plugins from some_playbook.yml that consumes a custom collection. The imported role can't see any variables.

# some_collection
galaxy.yml
playbooks
 |_playbook.yml
roles
 |_autopatch  <-- is templated i.e. do auto patching and take "datetime" as variable
 |_role2

Ideal case for host_vars as it can be per-host. Obviously if I have 2 servers in a cluster I can't hardcode the date and have them reboot at the same time.

inventory
collections.yml
group_vars
host_vars
some_playbook.yml

---
# some_playbook.yml
- hosts: all
  name: 
  tasks:
    import_role: namespace.some_collection.autopatch

Right now I get

TASK [namespace.some_collection.autopatch : Setup autopatch cron file] *****************************************************************************************************************
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible.errors.AnsibleUndefinedVariable: 'datetime' is undefined

Now, I can do this, but it doesn't really scale with hosts: all.

  tasks:
    import_role: namespace.some_collection.autopatch
  vars:
    datetime: "yolo"

Answer 1

Of course this is possible, just figured out what my problem was and it's dumb.

I'm in the middle of migrating from a monolithic ansible repo to collections based with flatter more concise structure (and we have ALOT of ansible). My group_vars/ and host_vars/ folders weren't top-level, they were nested in the inventory directory, with that fixed:

inventory
collections.yml
group_vars
host_vars
  |_hostname1
       |_base.yml         # <--- put host_var here
  |_hostname2
       |_base.yml         # <--- put host_var here
some_playbook.yml

---
# base.yml
the_hosts_specific_datetime: some_time

I did find that passing datetime: "{{ datetime }}" causes a recurrsion error so naming the var something specific allows you to pass it into a collection.

- import_role: 
  name: namespace.some_collection.autopatch
  vars:
    datetime: "{{ the_hosts_specific_datetime }}"