=============
Best Practice
=============


Debugging a playbook
====================

With the --check parameter a dry run is possible.

.. code-block:: bash

   ansible-playbook -i hosts --check myservice.yml


Use the parameter "--start-at-task=<TASKNAME>" on your call to ansible-playbook.

.. code-block:: bash

   ansible-playbook -i hosts myPlaybook.yml --start-at-task="test echo"


Or use "--step" and there will be a question for all tasks if you want to proceed to the next.

.. code-block:: bash

   ansible-playbook -i hosts myPlaybook.yml --step


List hosts targeted in a playbook.

.. code-block:: bash

   ansible-playbook myPlaybook.yml --list-hosts


List all tasks in a playbook. This may be usefull to gather an overview of a big amount of tasks in a plabook.

.. code-block:: bash

   ansible-playbook myPlaybook.yml --list-tasks


Take use of the debug module.

.. code-block:: yaml

   - name: test echo
     shell: echo I failed
     register: output

   - debug: msg="Okay stop the playbook"
     failed_when: output.stdout.find('failed')!=-1


Use debug module to debug a variable or dictionaries. The task 'test echo' will only be run when verbosity from commandline matches the given verbosity level.

.. code-block:: yaml

   - shell: /usr/bin/uptime
     register: output

   - name: test echo
     debug: var=output verbosity=1

.. code-block:: bash

   ansible-playbook -i hosts myPlaybook.yml -v


Debugging ssh Connection
========================

Append the known -v (verbose) parameter to your ansible or ansible-playbook command

.. code-block:: bash

   ansible testServer -i hosts -m ping -vvvv