ansible/ansible — pull request #3066 by lorin (2013-05-30 18:38:16+00:00)
Title: Optionally fail task on undefined variables

This patch introduces a new configuration option called `error_on_undefined_vars`, which defaults to false.

If this option is set to true, then a task which has unevaluated variables in its arguments will fail instead of running. Output looks like this:

TASK: [set rabbitmq password] *************************************************
fatal: [10.20.0.7] => Undefined variables: rabbitmq_user, rabbitmq_password