Ansible Generate List of Compliying hosts - networking

Question

I'm trying to generate a list with the information of hosts that match a certain condition (for instance, that NTP is synched for an inventory of Cisco devices). So that the ones matching that condition will be added to a list with say hostname and IP, for later generating a CSV.
Checking the condition is quite easy, but I'm struggling on how to generate this list.
Adding them to a list in a var doesn't seem wise, as it requires of serial execution of tasks per device.
Should I set a boolean fact for each device (i.e., ntp_synched, and then generate a list with the ansible_net_hostname and ansible_host of each device? How to do this?
- name: CHECK NTP STATUS
ios_command:
commands:
- show ntp status
register: ntp_status
- name: NTP NOT SYNCH
debug:
msg: "{{ [ansible_net_hostname] }}"
when: '"Clock is synchronized" not in ntp_status.stdout[0]'

Answer 1

For example, given the inventory for testing
host01 status="Clock is synchronized"
host02 status="Clock is synchronized"
host03 status="Clock is not synchronized"
Create the dictionary of the hosts and statuses
- hosts: all
tasks:
- command: "echo {{ status }}"
register: ntp_status
- set_fact:
host_status: "{{ dict(_hosts|zip(_stats)) }}"
vars:
_hosts: "{{ ansible_play_hosts }}"
_stats: "{{ ansible_play_hosts|
map('extract', hostvars, ['ntp_status','stdout'])|list }}"
run_once: true
gives
host_status:
host01: Clock is synchronized
host02: Clock is synchronized
host03: Clock is not synchronized
List the synchronized hosts
- debug:
msg: "{{ host_status|dict2items|
selectattr('value', 'search', 'Clock is synchronized')|
map(attribute='key')|list }}"
run_once: true
gives
msg:
- host01
- host02