How to use variables defined through vars_prompt of one host in another host vars? - ansible

Question

I am having 2 plays in a playbook. One of them prompts for input from user and I want to use that variable in another play. Please suggest me how to do that
---
- hosts: workers
gather_facts: false
sudo: true
vars_prompt:
- name: "server_ip"
prompt: "Enter the Server IP"
private: no
roles:
- client-setup-worker
- hosts: master
gather_facts: false
sudo: true
vars:
server: "{{ hostvars['workers']['server_ip'] }}"
roles:
- client-setup-master
In the above playbook I want to use server_ip defined in workers hosts to be used in master hosts.
I am facing the error "The error was: \"hostvars['workers']\" is undefined" while doing so

Answer 1

I am facing the error "The error was: \"hostvars['workers']\" is undefined" while doing so
That's because workers is evidently a group, and not a host, which is the only thing one will find declared in hostvars
You'll need to grab one of the hosts at random from the workers group, and then extract its fact; I believe this will do that:
update after seeing the mostly correct answer by #VladimirBotka
- hosts: workers
vars_prompt:
# as before ...
pre_tasks:
- name: re-export the vars_prompt for cross playbook visibility
set_fact:
server_ip: '{{ server_ip }}'
roles:
# as before
- hosts: masters
vars:
server: '{{ hostvars[(groups.workers|first)].server_ip }}'

Answer 2

The scope of variables declared in vars_prompt is the play.
Such variable may be put into the hostvars by set_facts "to use that variable in another play". For example the play below
- hosts: test_01
gather_facts: false
vars_prompt:
- name: "server_ip"
prompt: "Enter the Server IP"
private: no
tasks:
- set_fact:
stored_server_ip: "{{ server_ip }}"
- debug:
var: stored_server_ip
- hosts: test_02
gather_facts: false
vars:
server: "{{ hostvars.test_01.stored_server_ip }}"
tasks:
- debug:
var: server
gives (abridged):
ok: [test_01] => {
"stored_server_ip": "10.1.0.10"
}
ok: [test_02] => {
"server": "10.1.0.10"
}