How make an alias resolve accordingly amongst different playbooks?

[Manos Seferidis]

I have been fighting with this issue for days. I have been trying to avoid roles, since my setup seems pretty simple.
Not even sure if roles are needed. You can find this question on stackoverflow as well.

My problem

Here's my inventory:

[development]
web_server ansible_connection=docker
db_server  ansible_connection=docker

[staging]
web_server ansible_host=20.20.20.20  ansible_user=tom  ansible_connection=ssh
db_server  ansible_host=20.20.20.20  ansible_user=tom  ansible_connection=ssh

[production]
web_server ansible_host=10.10.10.10  ansible_user=tom  ansible_connection=ssh
db_server  ansible_host=10.10.10.10  ansible_user=tom  ansible_connection=ssh

My issue now is that I can't figure a way of having my three playbooks: production.yml, staging.yml, development.yml to resolve the web_server and db_server aliases to the appropriate machines. I want to use those aliases throughout my tasks and playbooks for consistency but nothing seems to work.

Things I've tried

This solution doesn't work since it runs all tasks twice!

---
- hosts: staging
  tasks:
    - name: Setup web server
      command: uptime
      delegate_to: web_server
    - name: Setup db server
      command: ls
      delegate_to: db_server
 

This solution solves the above problem but it prints the wrong alias (web_server even when running the db task).

---
- hosts: staging
  run_once: true
  tasks:
    - name: Setup web servers
      command: uptime
      delegate_to: web_server
    - name: Setup db servers
      command: ls
      delegate_to: db_server

This solution suggested by someone at stackoverflow doesn't work either (although without errors). web_server and db_server resolve to the wrong machine.

---
- hosts: staging:web_server
  tasks:
    - name: Deploy to web server
      command: uptime
---
- hosts: staging:db_server
  tasks:
    - name: Deploy to db server
      command: ls

This solution would be ideal but Ansible does not support access to an individual host from a group from what I know:

---
- hosts: web_server
  tasks:
    - name: Setup web server
      command: uptime
- hosts: db_server
  tasks:
    - name: Setup db server
      command: ls

[Brian Coca]

I used to do this in 3 inventories production, staging, development, then you can have single play and just use -i /path/to/production on playbooks to choose your environment (ops could also use -i /path/to to point at all servers).