Print variables from Ansilbe host file in playbook

Question

Trying to fetch variable value in playbook, but is yielding to error as per below. Any suggestions to resolve variable?

Here is (eg dynamic ) inventory file ( where group name is not known in playbook )

$ cat ans_hosts
[gname_tools]
<machine_name_goes_here>
<machine_name_goes_here>
<machine_name_goes_here>

[gname_tools:vars]
group_name=gname_tools
clip_id=3
[email protected]

Here is playbook

$ cat var_access.yml
---
- hosts: all
  connection: local
  gather_facts: false

  tasks:
   - name: Print Inventory variable
     shell: |
       cmd: |
         echo "{{hostvars['group_name']}}"
     register: ExcepStatus
     delegate_to: localhost

   - debug: msg="{{ExcepStatus.stdout}}"

Here is result of running playbook

$ ansible-playbook -i ans_hosts var_access.yml
PLAY [all] **************************************************************************************************************************************************

TASK [Print Inventory variable] *****************************************************************************************************************************
fatal: [<machine_name_goes_here> -> localhost]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: \"hostvars['group_name']\" is undefined\n\nThe error appears to be in '/home/gollip/ans/var_access.yml': line 7, column 6, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n  tasks:\n   - name: Print Inventory variable\n     ^ here\n"}

PLAY RECAP **************************************************************************************************************************************************
<machine_name_goes_here>   : ok=0    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

Answer 1

hostvars is a dict of hosts, where each key is a dict of host variables. To fetch a variable from hostvars, you should first specify the host whose variables you want to access:

- debug:
    var: hostvars['<machine_name_goes_here>']['group_name']

Answer 2

For an inventory file

[test]
one.example.com
two.example.com

[test:vars]
[email protected]

a minimal example playbook

---
- hosts: test
  become: false
  gather_facts: false

  tasks:

  - debug:
      var: hostvars[inventory_hostname].group_names

  - debug:
      msg: "{{ hostvars[inventory_hostname]['MAIL'] }}"

will result into an output of

TASK [debug] ******************************
ok: [one.example.com] =>
  hostvars[inventory_hostname].group_names:
  - test
ok: [two.example.com] =>
  hostvars[inventory_hostname].group_names:
  - test

TASK [debug] ******************************
ok: [one.example.com] =>
  msg: [email protected]
ok: [two.example.com] =>
  msg: [email protected]

Or in short

  - debug:
      msg: "{{ group_names | first }} and {{ MAIL }}"

will output

TASK [debug] **********************
ok: [one.example.com] =>
  msg: test and [email protected]
ok: [two.example.com] =>
  msg: test and [email protected]