Ansible and nested variables in loops - loops

Question

I there a way in Ansible to access variables in variables in a loop? For instance, configuring debconf to install a MySQL/MariaDB server needs two instructions like so:
- name: Define maria root password
shell: echo mysql-server mysql-server/root_password password {{ mysqlRootPass }} | debconf-set-selections
- name: Define maria root password again
shell: echo mysql-server mysql-server/root_password_again password {{ mysqlRootPass }} | debconf-set-selections
But that would be way more compact if I could do that:
- name: Define maria root password
shell: {{ item }}
with_items:
- "{ echo mysql-server mysql-server/root_password password {{ mysqlRootPass }} | debconf-set-selections }"
- "{ echo mysql-server mysql-server/root_password_again password {{ mysqlRootPass }} | debconf-set-selections }"
Obviously, that doesn't work.
so is there a way to make it work? Is there a better way of doing it? Am I missing something?

Answer 1

The {{ }} notation in Ansible comes from Jinja2 templates, it essentially directs Ansible to replace this with the contents of that variable.
with_items introduces the special variable item, which is the particular item of the current loop.
Therefore, you instruct the command module to execute { echo..., namely whatever it is you have in with_items. You only need the command itself: echo....
Reference: Ansible docs: using variables and Jinja2

Answer 2

Here is my complete working MySQL role, that might help you.
vars/main.yml
mysql_root_pass: mypassword #MySQL Root Password
tasks/main.yml
---
- name: Install the MySQL packages
apt:
name: "{{ item }}"
state: installed
update_cache: yes
with_items:
- mysql-server-5.6
- mysql-client-5.6
- python-mysqldb
- libmysqlclient-dev
- name: Update MySQL root password for all root accounts
mysql_user:
name: root
host: "{{ item }}"
password: "{{ mysql_root_pass }}"
state: present
with_items:
- "{{ ansible_hostname }}"
- 127.0.0.1
- ::1
- localhost
- name: Copy the root credentials as .my.cnf file
template:
src: root.cnf.j2
dest: "~/.my.cnf"
mode: 0600
- name: Ensure Anonymous user(s) are not in the database
mysql_user:
name=''
host: "{{ item }}"
state: absent
with_items:
- localhost
- "{{ ansible_hostname }}"
- name: Remove the test database
mysql_db:
name: "test"
state: absent
notify:
- Restart MySQL
templates/root.cnf.j2
[client]
user=root
password={{ mysql_root_pass }}
handlers/main.yml
---
- name: Restart MySQL
service:
name: mysql
state: restarted
My site.yml look like this:
---
- hosts: all
become: yes
gather_facts: yes
roles:
- mysql
If you are just looking to update the password of already configured MySQL:
In vars/main.yml
mysql_old_root_pass: olmysqldpassword
mysql_root_pass: newmysqlpassword
In tasks/main.yml
- name: Set root user password
mysql_user:
name: root
host: "{{ item }}"
password: "{{ mysql_root_pass }}"
check_implicit_admin=yes
login_user: root
login_password: "{{ mysql_old_root_password }}"
state: present
with_items:
- "{{ ansible_hostname }}"
- 127.0.0.1
- ::1
- localhost
Hope this will help you. If you need any help, please check this github link.