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Ansible user module and password hashing

Apr 28, 2022 · 2 mins read · Post a comment
Ansible user module and password hashing

As far as I know, there are two secure ways (discussable) you could include a password as part of the Ansible user module. Let’s go throught it.

Prerequisites

  • Ansible

Solutions

Solution 1. Use SHA-512 password with a salt

Step 1. Generate SHA512 password hash with a salt from the CLI.

Step 2. Add the hashed password with a salt value to an Ansible task. For instance:

- name: Add the user 'devcoops' with a specific uid and a primary group of 'sudo'
  user:
    name: devcoops
    comment: DevOps engineer
    uid: 1051
    group: sudo
    password: <password_value_here_generated_from_step_1>
  tags:
    - users

Note(s). Few things to consider:

  1. Simpler solution.
  2. Doesn’t scale well.

Solution 2. Use Ansible Vault

Ansible Vault is an encryption / decryption utility tool used mostly for storing and securing sensitive vars. Now, create a vault file if you haven’t done it already, and add password and password_salt variables.

Step 1. Create a vault file.

ansible-vault create vault

Step 2. You’ll be prompt for vault password. Once done, edit the vault file.

ansible-vault edit vault

Step 2. Once prompt for the vault password, add the secret variables.

password: <some_password_here>
password_salt: <some_password_salt_here>

Step 3. Create a playbook or add the following task below as part of your existing one.
Example playbook:


---
- name: Create new users
  hosts: all
  become: true
  gather_facts: false
  vars_files:
    - vault
  tasks:
    - name: Create new users
      user:
        name: "{{ item }}"
        password: "{{ password | password_hash('sha512', password_salt) }}"
        shell: /bin/bash
        update_password: on_create
      loop:
        - devcoops
        - bob
        - alice
      tags:
        - users

Note(s). A couple of things to consider:

  1. The password_salt var will prevent the task getting “changed” every time it runs.
  2. New users will share the same password and password_salt initially. Not a big deal though as long as the users login in a short period of time, hence getting prompt to update their password.
  3. This isn’t a granular approach, if you wanna set parameters like uid, group, comment.
  4. Although encrypted, the Ansible vault file will be part of VCS, so you might wanna consider migrating to a more well-rounded secret management solution, HashiCorp Vault for instance.

Conclusion

If you can think of any other alternative solution, please do let me know in the comment section below. On a side note, follow our official channel on Telegram.