9 ansible commands to start with

Quick reference

Can I reach the hosts?

# check SSH and Python on every host
$ansible all -m ping
# gather facts: OS, IP, memory, and more
$ansible all -m setup
# run one command on a group of hosts
$ansible web -a 'uptime'

Make changes

# install a package. -b runs with sudo
$ansible web -b -m apt -a 'name=nginx state=present'
# restart a service everywhere at once
$ansible web -b -m service -a 'name=nginx state=restarted'
# push a file to every host
$ansible web -b -m copy -a 'src=app.conf dest=/etc/app/'

Repeatable runs

# dry run: see what would change
$ansible-playbook site.yml --check
# run against one host first
$ansible-playbook site.yml --limit web01
# keep secrets encrypted at rest
$ansible-vault edit secrets.yml

Explained

Can I reach the hosts?

ansible all -m ping is the first test. It confirms Ansible can reach each host over SSH and run Python there. It is not a network ping; it is an end-to-end check. ansible all -m setup gathers facts about each host: OS, IP addresses, memory, disks. These facts are what playbooks use to make decisions. ansible web -a 'uptime' runs a single command on every host in the web group. Great for quick checks across a fleet.

Make changes

ansible web -b -m apt -a 'name=nginx state=present' installs a package everywhere. -b means become, running with sudo. Modules like apt are idempotent: run them again and nothing changes if nginx is already there. ansible web -b -m service -a 'name=nginx state=restarted' restarts a service across the whole group at once. ansible web -b -m copy -a 'src=app.conf dest=/etc/app/' pushes a file to every host.

Repeatable runs

ansible-playbook site.yml --check is a dry run. It shows what would change without changing anything. Always run this first. ansible-playbook site.yml --limit web01 runs a playbook against one host before the whole fleet. ansible-vault edit secrets.yml keeps secrets encrypted at rest, so credentials never sit in plain text in your repo.

The path: ad-hoc commands to learn, playbooks to make it repeatable.

In one line

Try it

$ansible all -m ping