$ ansible-playbook webserver.yml -i hosts/local

ansible/
    webserver.yml
    apserver.yml
    dbserver.yml

    hosts/
          local
          production
          staging
          test

    roles/
        common-centos6/
            files/
                xxxx.rpm
                xxxx.sh
                xxxx.conf
            tasks/
                main.yml

        nginx/
            files/
                xxxx.rpm
                xxxx.sh
                xxxx.conf
            tasks/
                main.yml

        mysql/
            files/
                xxxx.rpm
                xxxx.sh
                xxxx.conf
            tasks/
                main.yml

-hosts: all
  become: yes
  roles:
    -common
    -nginx

Ansible CLI Commands Cheet Sheat and Configuration Examples