Ansible: Generating a SSH pub key file and uploading to other host to sync files from there

Update: check the comments for new workflows

Original from 19/May/2014... updated!

I found this workflow for our systems:

1. Up the new box.
2. Generate keys in that new box.
3. "Fetch" the pub key from the new server to the ansible server.
4. Copy that key to authorized_keys file of the other server (from ansible server).
5. Execute a rsync from the new server without asking key to the other server.

My trick is: