Ansible - run two tasks in parallel - ansible

Question

My playbook is as following... this is related to one host not several at once:
---------------- Deregister from TG's
- name: DeRegister instance ID from a Public TG
elb_target:
target_group_name: "{{ TG_public }}"
target_id: "{{ Instance_ID }}"
state: absent
target_status: unused ## wait until this status
target_status_timeout: 300 ## in seconds
profile: "{{ profile_ID }}" ## specify AWS profile
delegate_to: 127.0.0.1 ## Execute this stage locally
- name: DeRegister instance ID from a Private TG
elb_target:
target_group_name: "{{ TG_private }}"
target_id: "{{ Instance_ID }}"
state: absent
target_status: unused ## wait until this status
target_status_timeout: 300 ## in seconds
profile: "{{ profile_ID }}" ## specify AWS profile
delegate_to: 127.0.0.1 ## Execute this stage locally
----------------------------------
The question how to execute above tasks in parallel... Please help

Answer 1

Use async and set
poll: 0
For example, in the playbook below, 2 commands sleep (10 seconds each) are used instead of the 2 commands from the question. The output shows that both tasks started the commands and terminated. The commands ran in parallel. The first task async_status waited for 3 iterations (3 seconds each) until the first command completed. The second task async_status completed immediately. The whole playbook ran for 11 seconds.
- hosts: localhost
tasks:
- debug:
msg: "{{ lookup('pipe', 'date') }}"
- command: /usr/bin/sleep 10 # Public TG
async: 45
poll: 0
register: public
- command: /usr/bin/sleep 10 # Private TG
async: 45
poll: 0
register: private
- debug:
msg: "{{ lookup('pipe', 'date') }}"
- async_status:
jid: "{{ public.ansible_job_id }}"
register: job_result
until: job_result.finished
retries: 100
delay: 3
- debug:
msg: "{{ lookup('pipe', 'date') }}"
- async_status:
jid: "{{ private.ansible_job_id }}"
register: job_result
until: job_result.finished
retries: 100
delay: 3
- debug:
msg: "{{ lookup('pipe', 'date') }}"
gives (abridged)
TASK [debug] ****
msg: Mon 12 Oct 2020 09:42:21 PM CEST
TASK [command] ****
TASK [command] ****
TASK [debug] ****
msg: Mon 12 Oct 2020 09:42:21 PM CEST
TASK [async_status] ****
FAILED - RETRYING: async_status (100 retries left).
FAILED - RETRYING: async_status (99 retries left).
FAILED - RETRYING: async_status (98 retries left).
TASK [debug] ****
msg: Mon 12 Oct 2020 09:42:32 PM CEST
TASK [async_status] ****
TASK [debug] ****
msg: Mon 12 Oct 2020 09:42:32 PM CEST
It is possible to wait for more jobs in a single loop. For example
- async_status:
jid: "{{ item.ansible_job_id }}"
loop:
- "{{ public }}"
- "{{ private }}"
register: job_result
until: job_result.finished
retries: 100
delay: 3