Ansible works by connecting to the nodes and pushing out a small program called Ansible modules to them. Then Ansible executed these modules and removed them after finished. The library of the modules can reside on any machine, and there are no daemons, servers, or databases required.
The Management Node is the controlling node that controls the entire execution of the playbook. The inventory files provide the list of hosts where the Ansible modules need to be run. The Management Node makes an SSH connection and executes the small modules on the host's machine and install the software.