Creating a hostgroup from a super-set of hosts

Question

I have two host files with different hosts, hostGroups and super-set in each file like below.

/ets/hostFiles/TestBoxes

[TestBox:children]
groupA
groupB

[groupA]
...
...

[groupB]
...
...

/ets/hostFile/ProdBoxes

[ProdBox:children]
groupPA
groupPB

[groupPA]
...
...

[groupPB]
...
...

Now i would like to create a Primary host group with TestBox and ProdBox

Please let me know if this is possible.

Note: This is just an example... I have 100+ files like this. and I want to create primary group with few of the files. hosts=all is not my requirement.

Answer 1

Use the constructed inventory plugin. See

shell> ansible-doc -t inventory constructed

Create the inventory files

shell> tree inventory/
inventory/
├── 01-TestBoxes
├── 02-ProdBoxes
└── 03-Primary.yml

0 directories, 3 files

shell> cat inventory/01-TestBoxes 
[TestBox:children]
groupA
groupB

[groupA]
host_1

[groupB]
host_2

shell> cat inventory/02-ProdBoxes 
[ProdBox:children]
groupPA
groupPB

[groupPA]
host_P1

[groupPB]
host_P2

shell> cat inventory/03-Primary.yml 
plugin: constructed
groups:
  Primary: (group_names | intersect(['ProdBox', 'TestBox'])) | length > 0

The playbook

shell> cat pb.yml 
- hosts: Primary
  gather_facts: false
  tasks:
    - debug:
        var: inventory_hostname

reads files from the directory inventory in alphabetic order. The file Primary.yml creates the group Primary from hosts that are members of the groups ProdBox and TestBox

shell> ansible-playbook -i inventory pb.yml 

PLAY [Primary] *******************************************************************************

TASK [debug] *********************************************************************************
ok: [host_1] => 
  inventory_hostname: host_1
ok: [host_2] => 
  inventory_hostname: host_2
ok: [host_P1] => 
  inventory_hostname: host_P1
ok: [host_P2] => 
  inventory_hostname: host_P2

PLAY RECAP ***********************************************************************************
host_1: ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host_2: ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host_P1: ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host_P2: ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Q: " I have 100+ files like this. and I want to create primary group with few of the files."

A: Create links

shell> tree inventory/
inventory/
├── 01-TestBoxes -> ../hostFiles/TestBoxes
├── 02-ProdBoxes -> ../hostFiles/ProdBoxes
└── 03-Primary.yml