Defining variables in a inventory

Content of first.tf

web1 ansible_ssh_host=192.168.33.20 ansible_ssh_user=vagrant ansible_ssh_pass=vagrant username=ansible_user 
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

[myInventory:vars]
some_var=some_value