Installing and Your First Command

Install on the control node only

Install Ansible on one machine (your laptop or a build server): on Debian/Ubuntu with sudo apt install ansible, or with pipx install ansible / pip install ansible. Managed hosts need only SSH and Python. An ad-hoc command runs one module once, without a playbook, for quick checks: ansible <hosts> -m <module> -a "<args>". The ping module checks that Ansible can connect and run Python; it is not an ICMP ping.

Ping the web group

I ran this on this machine with ansible_connection=local hosts (so no SSH is needed for the demo). pong means the module ran successfully.

ansible --version | head -1
ansible -i inventory.ini web -m ping

Output:

ansible [core 2.16.3]
web1 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python3"
    },
    "changed": false,
    "ping": "pong"
}
web2 | SUCCESS => { ... same ... }

Ad-hoc for quick facts, playbooks for repeatable work

Use ad-hoc commands to check uptime or disk space across servers. Anything you will run twice belongs in a playbook under version control.

Quick check: Where must Ansible be installed?

• Only on the control node
• On every managed host
• Inside every container image
• Nowhere, it is a website