Start postgresql either by a supervisor program called postgresql or, if this is not defined,
through the sustem service. This is required in the context of various galaxyproject ansible roles [1] [2] [3].
1 - https://github.com/galaxyproject/ansible-galaxy-extras
2 - https://github.com/galaxyproject/ansible-galaxy
3 - https://github.com/natefoo/ansible-postgresql-objects