Defining variables in a inventory group_vars and host_vars

Content of first.tf

PS D:\production> tree /F
Folder PATH listing
Volume serial number is A0D4-D536
D:.
│   ansible.cfg
│   inventory_prod
│
├───group_vars
│       all
│       db
│       webservers
│
└───host_vars
        web1
		
#Content of web1
---
username: web1_user


#Content of webservers
---
username: group_user


#Content of all
---

username:  all_username


#Content of inventory_prod
web1 ansible_ssh_host=192.168.33.20 
db1 ansible_ssh_host=192.168.33.30 
[webservers]
web1

[dbservers]
db1

[datacenter:children]
webservers
dbservers

[datacenter:vars]
ansible_ssh_user=vagrant
ansible_ssh_pass=vagrant