Vagrant configuration with Ansibles.postgresql — Currently with errors

playbook.yml

---
- hosts: all
  vars_files:
    - vars_main.yml
  roles:
    - Ansibles.postgresql

Vagrantfile

VAGRANTFILE_API_VERSION = "2"
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
  config.vm.box = "ubuntu/trusty64"
  config.vm.network "forwarded_port", guest: 5432, host: 5432
  config.vm.provision "ansible" do |ansible|
    ansible.playbook = "playbook.yml"
    ansible.sudo = true
    ansible.verbose = 'vvv'
  end
end

vars_main.yml

postgresql_ext_install_contrib: yes
postgresql_databases:
  - name: mydb
    uuid-ossp: yes

# This line results in problems
postgresql_data_directory: "/vagrant/_data/{{postgresql_version}}/{{postgresql_cluster_name}}"
postgresql_listen_addresses:
  - "*"
postgresql_port: 5432

# This line also results in problems
postgresql_pg_hba_default:
   - { type: local, database: all, user: all, address: '0.0.0.0/0', method: "{{ postgresql_default_auth_method }}", comment: '' }
   - { type: local, database: all, user: all, address: '::1/0', method: "{{ postgresql_default_auth_method }}", comment: '' }