Ansible

Agentless config management & orchestration over SSH.

Ad-hoc commands

```
ansible all -m ping
```
Cheapest health check across the inventory — confirms SSH + python.
```
ansible all -m setup
```
Dump every fact (gathered variable) for every host.
```
ansible web -m shell -a 'uptime'
```
Run an arbitrary shell command on a host group.

ansible web -m apt -a 'name=nginx state=present' -b

Install a package — -b becomes root.

ansible all -m copy -a 'src=./hosts dest=/etc/hosts' -b

Push a file to every host.

```
ansible-inventory --list
```
Print the inventory as JSON. Useful for dynamic inventory debugging.
```
ansible-inventory --graph
```
Tree view of groups + hosts.
```
ansible all --list-hosts
```
Just the host names matching a pattern.
```
ansible -i hosts.ini web --list-hosts
```
Use a non-default inventory file.

```
ansible-playbook site.yml
```
Run a playbook against the inventory.
```
ansible-playbook site.yml --check
```
Dry-run: report what would change without applying.
```
ansible-playbook site.yml --diff
```
Show before/after diffs for files Ansible modifies.

ansible-playbook site.yml --tags 'nginx,tls'

Only tasks tagged matching.

```
ansible-playbook site.yml --limit web01
```
Only run against one host (or pattern).
```
ansible-playbook site.yml -K
```
Prompt for sudo (become) password.

```
ansible-vault create secrets.yml
```
Create a new encrypted file.
```
ansible-vault edit secrets.yml
```
Decrypt → open in $EDITOR → re-encrypt on save.
```
ansible-vault view secrets.yml
```
Print the decrypted contents to stdout.

ansible-vault encrypt_string 'shh' --name 'db_password'

Encrypt a single value to paste into a YAML file.

```
ansible-playbook site.yml --ask-vault-pass
```
Prompt for the vault password at runtime.

```
ansible-galaxy init my_role
```
Scaffold a fresh role with the standard directory layout.
```
ansible-galaxy install -r requirements.yml
```
Pull external roles/collections from Galaxy or git.

ansible-galaxy collection install community.general

Install a collection.