Had a client with a deployment tool that would copy a bundle of Ansible to each host and run ansible-playbook locally on each host defined. This had some interesting side effects where you want to the same play on multiple hosts
E.g.
[webservers]
host1.domain.net ansible_connection=local
host2.domain.net ansible_connection=local
Normally this would force all members of the webservers group to be run locally, so used the following little block:
- hosts: webservers
tasks:
- name: foo
debug:
msg: "test message for - - "
when: ansible_host == ansible_hostname