ansible doesn't find the role mentioned in the playbook

Question

I'm pretty new with Ansible so I might configured things wrong
[I have a Docker container running Ansible service in it
I have an Ansible repository that include the Ansible files (this is a .Git repository]

My will was to automatically revert each lab in vCenter server to a specific snapshot
So, I (with the help of ansible-roles-explained-with-examples guide):

• Created a role with ansible-galaxy init command name vcenter (see directory tree below)
• Created some vcenter tasks files inside tasks folder (see directory tree below). Here is an example of rever.yml task file:

- name: Revert to a snapshot
  vmware_guest_snapshot:
    hostname: "{{ vcenter_hostname }}"
    username: "{{ vcenter_username }}"
    password: "{{ vcenter_password }}"
    datacenter: "{{ datacenter_name }}"
    state: revert
    snapshot_name: CLEAN
  delegate_to: localhost

• Supplied vCenter credentials in vcenter\vars\main.yml file, like this:

# vars file for vcenter
vcenter_hostname: vcenter.foo.com
vcenter_username: hiddai@foo.com
vcenter_password: f#0$o#1$0o

• Included the tasks in tasks\main.yml file with import-task key, like this:

---
# tasks file for roles/vcenter
- import_tasks: poweroff.yml
- import_tasks: poweron.yml
- import_tasks: revert.yml
- import_tasks: shutdown.yml

• Created a revert_lab.yml playbook that include the role, like this

---
- name: revert an onpremis lab
  hosts: all
  roles:
  - vcenter

Before I executed the playbook to revert all the machines in the lab, I ran a little check of the playbook syntax:

ansible-playbook playbooks/revert_lab.yml --syntax-check

The error I got was:

[WARNING]: Ansible is being run in a world writable directory (/ansible), ignoring it as an ansible.cfg source. For more information see
https://docs.ansible.com/ansible/devel/reference_appendices/config.html#cfg-in-world-writable-dir
[DEPRECATION WARNING]: Ansible will require Python 3.8 or newer on the controller starting with Ansible 2.12. Current version: 3.6.8 (default, Nov 16 2020, 16:55:22) [GCC
 4.8.5 20150623 (Red Hat 4.8.5-44)]. This feature will be removed from ansible-core in version 2.12. Deprecation warnings can be disabled by setting 
deprecation_warnings=False in ansible.cfg.
[WARNING]: No inventory was parsed, only implicit localhost is available
[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'
ERROR! the role 'vcenter' was not found in /ansible/playbooks/roles:/root/.ansible/roles:/usr/share/ansible/roles:/etc/ansible/roles:/ansible/playbooks

The error appears to be in '/ansible/playbooks/revert_lab.yml': line 5, column 5, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

  roles:
  - vcenter
    ^ here

I decided to add ansible.cfg to my repository with the a roles_path key:

[defaults]
inventory = /ansible/inventories
roles_path = /ansible/roles
# roles_path = ./roles:..~/ansible/roles

I ran again the --syntax-check command but got the same error. I tried different kind of role path statments - and got the same error. Of course ansible-playbook command wasn't work (with the same error message):

ansible-playbook playbooks/revert_lab.yml -i inventories/test/onpremis/domain.com/lab_r.yml

So, How do I make ansible to recognize my role?
How do I make ansible to run successfully my playbook?
Is ansible.cfg relevant or irrelevant to the "story"?

My repository:

C:.
├───ansible
│   │   ansible.cfg
│   ├───inventories
│   │   └───test
│   │       ├───cloud
│   │       └───onpremis
│   │           └───domain.com
│   │               │   lab_j.yml
│   │               │   lab_r.yml
│   │               └───group_vars
│   │                       all.yml
│   ├───playbooks
│   │       revert_lab.yml
│   └───roles
│       └───vcenter
│           ├───tasks
│           │       main.yml
│           │       poweroff.yml
│           │       poweron.yml
│           │       revert.yml
│           │       shutdown.yml
│           └───vars
│                   main.yml

Answer 1

Ansible told you what is wrong:

[WARNING]: Ansible is being run in a world writable directory (/ansible), ignoring it as an ansible.cfg source. For more information see https://docs.ansible.com/ansible/devel/reference_appendices/config.html#cfg-in-world-writable-dir

This means your changes in ansible.cfg are ignored.

Fix the permissions on this directory and try again.