By default, ansible ships with a ‘paramiko’ SSH, native ssh (just called ‘ssh’), ‘local’ connection type, and there are also some minor players like ‘chroot’ and ‘jail’. All of these can be used in playbooks and with /usr/bin/ansible to decide how you want to talk to remote machines. The basics of these connection types are covered in the 新手上路 section. Should you want to extend Ansible to support other transports (SNMP? Message bus? Carrier Pigeon?) it’s as simple as copying the format of one of the existing modules and dropping it into the connection plugins directory. The value of ‘smart’ for a connection allows selection of paramiko or openssh based on system capabilities, and chooses ‘ssh’ if OpenSSH supports ControlPersist, in Ansible 1.2.1 an later. Previous versions did not support ‘smart’.

More documentation on writing connection plugins is pending, though you can jump into lib/ansible/plugins/connections and figure things out pretty easily.