root@master_ubuntu1604server:~/playbooks# cat /etc/ansible/hosts
[linux-dev-servers]
testserver1
testserver2
root@master_ubuntu1604server:~/playbooks# ansible-playbook --syntax-check linux_patch_install.yml
root@master_ubuntu1604server:~/playbooks# ansible-playbook -i /etc/ansible/hosts -l linux-dev-servers linux_patch_install.yml