Ansible nested definition and reference issues

Question

I have a problem with implementing Ansible nested reference YAML variable file.

Example of user dictionary file variable:

User dictionary file variable, dev_infra_bastion_0_example_com is node FQDN name

# user varialbe file
root@dev-infra-bastion-0:~/ansible-stats# hostname
dev-infra-bastion-0.example.com

vars/user.yml

dev_infra_bastion_0_example_com:
  admin:
    - admin1
    - admin2
    - admin3
  people:
    - peopl1
    - peopl2
    - peopl3

I want to pass the dictionary defined in the vars/user.yml file after parsing through this playbook

## create hosts user
- hosts: test1
  become: yes
  vars_files:
    - vars/user.yml

  pre_tasks:
  - name: debug
    debug:
      msg: "{{ ansible_nodename.replace('-','_').replace('.','_') }}"
    register: mess

  - name: debug mess
    debug:
      msg: "{{ mess }}"

Run info

PLAY [test1] *******************************************************************************************************************************************************************************************************

TASK [debug] *******************************************************************************************************************************************************************************************************
ok: [10.1.204.100] => {
    "msg": "dev_infra_bastion_0_example_com"
}

TASK [debug mess] **************************************************************************************************************************************************************************************************
ok: [10.1.204.100] => {
    "msg": {
        "changed": false,
        "failed": false,
        "msg": "dev_infra_bastion_0_example_com"       #Here,Should be a dictionary,but it's string
    }
}

PLAY RECAP *********************************************************************************************************************************************************************************************************
10.1.204.100               : ok=2    changed=0    unreachable=0    failed=0

debug ------------------------------------------------------------------- 0.10s
debug mess -------------------------------------------------------------- 0.06s

user_2123530 · Answer

There is two to three things wrong in your playbook.

Do not use a debug and register if you want to register a variable, use the appropriate set_fact module
```
- set_fact:
    mess: "{{ ansible_nodename.replace('-','_').replace('.','_') }}"
```
If you want to access a variable from a variable, you need to either use the vars lookup.
```
- debug:
    var: lookup('vars', mess)
```
Bonus: to replace multiple characters by an underscore, maybe a regex_replace could be nicer, so, you can really do it in a single task:
```
- debug:
    var: lookup('vars', ansible_nodename | regex_replace('[\.-]', '_'))
```

An example playbook would be:

- hosts: localhost
  gather_facts: no

  tasks:
    - debug:
        var: lookup('vars', ansible_nodename | regex_replace('[\.-]', '_'))
      vars:
        ansible_nodename: dev-infra-bastion-0.example.com
        dev_infra_bastion_0_example_com:
          admin:
            - admin1
            - admin2
            - admin3
          people:
            - peopl1
            - peopl2
            - peopl3

Which would yield the recap:

PLAY [localhost] **************************************************************************************************

TASK [debug] ******************************************************************************************************
ok: [localhost] => 
  lookup('vars', ansible_nodename | regex_replace('[\.-]', '_')):
    admin:
    - admin1
    - admin2
    - admin3
    people:
    - peopl1
    - peopl2
    - peopl3

PLAY RECAP ********************************************************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Ansible nested definition and reference issues

1 Answers