Ansible

#Run Tasks With a Specific Tag

ansible-playbook -i inventory -vv site.yml --tags files

#Generate Password for PostgresSQL Task

# shell
env PW=`pwgen -ynN 1 20` sh -c 'printf "%s\tmd5%s\n" "$PW" `echo -n "$PW" | md5`'

#Set Inventory Variable for all Hosts

Set the python interpreter to use on all nodes:

[all:vars]
ansible_python_interpreter=/usr/bin/python2.7

#Create new Role Skeleton

# shell
mkdir -p roles/some_role_name/{tasks,files,handlers,templates,meta}

#Reboot Ansible Managed Servers

ansible all -i inventory -a "/sbin/reboot" -u root
host.example.com | FAILED => SSH Error: data could not be sent to the remote host. Make sure this host can be reached over ssh

The error can be ignored and is due to the server going down and becoming inaccessible.