Running a task only once

At times, a specific task in a role may need to be executed only once during a playbook execution, even though the role is applied to many hosts. This could be achieved with the run_once conditional:

name: initialize wordpress database
script: initialize_wp_database.sh 
run_once: true

Since we are using the run_once option, the preceding task would run on the first host in the inventory that the role is being applied to. All consequent hosts would skip this task.