Ansible Utils Commands

NB: As an example, the machines are defined in file inventory.yaml with the following content:

# VMs
all:
  hosts:
    vm01:
    vm02:
    vm03:
    vm04:
    vm05:
    vm06:

# Groups
dev:
  hosts:
    vm01:
    vm02:

test:
  hosts:
    vm03:
    vm04:

prod:
  hosts:
    vm05:
    vm06:

# Parent Groups
lan:
  children:
    dev:
    test:
wan:
  children:
    prod:

⚠ If you did not name your inventory file inventory.yaml at root folder, you’ll need to add the argument -i <inventory_filename> to all the commands in the following post.

List hosts from inventory

ansible --list-hosts <groups>

e.g.

# list all hosts
$ ansible --list-hosts all
  hosts (6):
    vm01
    vm02
    vm03
    vm04
    vm05
    vm06

# list a group
$ ansible --list-hosts wan
  hosts (2):
    vm05
    vm06


# list a top group
$ ansible --list-hosts lan
  hosts (4):
    vm01
    vm02
    vm03
    vm04

Run module on specific host or group

e.g.

Ping all hosts of group wan

$ ansible -m ping wan
vm05 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
vm06 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

execute ’echo world’ on host vm01

$ ansible -m shell -a "echo 'hello world'" vm01
vm01 | CHANGED | rc=0 >>
hello world

Generate a template locally

Very useful for local debug and avoiding additional code in your playbook or task files in role.

# Generate the file /tmp/prometheus.yml from template roles/prometheus/templates/prometheus.yml
$ ansible [--vault-password-file=~/.pass.txt] -m template -a "src=roles/prometheus/templates/prometheus.yml dest=/tmp/prometheus.yml" localhost

# Check the generated file locally
$ promtool check config /tmp/prometheus.yml

Encryption/Decryption using ansible-vault

Documentation: https://docs.ansible.com/ansible/latest/cli/ansible-vault.html

Using vault password file

# File Encryption
ansible-vault encrypt --vault-password-file ~/.pass.txt roles/ssl/files/private.key
# File Decryption
ansible-vault decrypt --vault-password-file ~/.pass.txt roles/ssl/files/private.key


# Variable Encryption
ansible-vault encrypt_string --vault-password-file ~/.pass.txt '<string_to_encrypt>' --name '<variable_name>'
e.g.
ansible-vault encrypt_string --vault-password-file ~/.pass.txt 'verystrongpassword' --name 'encrypted_var_name'
# Print variable Decryption
ansible -m debug -a var=encrypted_var_name localhost --vault-password-file ~/.pass.txt