simple video tutorial
OBS: ansible uses py, and py calls /bin/sh, NOT bash !

PRE-CONFIG

suggested: use ssh-pub-key auth without passphrase.

INSTALL

Optioanl: add ppa:ansible/ansible
installation:

sudo apt-get update && \
sudo apt-get install ansible

HOSTS

vim /etc/ansible/hosts

master.ip.1
[slaves]
slave.domain1
slave.ip.addr.2
[slavesGroup2]
slave.domain2
slave.ip.addr.1

(see ref to give hosts' names individually.)

SLAVE USERNAME

sudo mkdir /etc/ansible/group_vars && \
sudo echo '---' > /etc/ansible/group_vars/all && \
sudo echo 'ansible_ssh_user: root' >> /etc/ansible/group_vars/all

(see DigitalOcean ref to config hosts individually.)

RUN

try:

ansible -m ping all

-m: module.

try:

ansible -m shell -a 'free -m' all

-a: arguments.

try:

ansibleall () { ansible -m shell -a "$@" all; }
ansibleall 'wget -O /etc/apt/sources.list https://goo.gl/H78Ihs' && \
ansibleall 'rm /etc/localtime && ln -fs /usr/share/zoneinfo/Etc/UTC /etc/localtime' && \
ansibleall 'apt-get update' && \
ansibleall 'apt-get install -y tmux vim ctags ntp mosh fail2ban sshguard locate'

ADVANCED

video: Ansible Playbook

echo 'ansibleall () { ansible -m shell -a "$@" all; }' >> ~/.bash_aliases
echo 'ansibleslaves () { ansible -m shell -a "$@" slaves; }' >> ~/.bash_aliases
echo 'ansiblemaster () { ansible -m shell -a "$@" master; }' >> ~/.bash_aliases

ref DigitalOcean