Home > Storage > PowerMax and VMAX > Storage Admin > Dell PowerMax: Ansible Modules Best Practices > Running a playbook
Playbooks are run using the Ansible-playbook command followed by the playbook name. Figure 13 shows a basic playbook running to provision storage for an application on a PowerMax array.
Figure 14 shows the same playbook run again with the same inputs; however, the play recap shows that no changes were made on the second run of the playbook. This is an example of idempotence in action. Because the modules detected that the storage was already configured in the way described by all the tasks, no changes were made.
One of the ways idempotency is maintained on storage with Dell modules for PowerMax is through reliance on storage group and volume names.
Best Practice: if you are checking for an object’s existence—for example, to determine if a storage group already exists before running another task—use the gather facts module, rather than use the idempotency of the storage group module, to avoid accidentally creating storage objects.