How to run playbook across multiple environments with their own group_vars? - ansible

Question

My current ansible structure looks something like this:
- inventory
- prod
- prod1
- hosts.yml
- group_vars
- all.yml
- prod2
- hosts.yml
- group_vars
- all.yml
- prod3
- hosts.yml
- group_vars
- all.yml
- nonprod
- dev
- hosts.yml
- group_vars
- all.yml
- qa
- hosts.yml
- group_vars
- all.yml
- uat
- hosts.yml
- group_vars
- all.yml
- roles
- main.yml (this isn't accurate just a sample playbook for the question)
I'd like to be able to run something like this: ansible-playbook main.yml -i inventory/prod and have it automatically cycle through the environments (each with distinct group_vars values).
Currently the command will find the hosts in each environment but not the vars which stops the playbook from running, but if I run ansible-playbook main.yml -i inventory/prod/prod1 it runs fine.

Answer 1

I would suggest restructuring your inventory. Ansible looks for the group_vars directory adjacent to your inventory files. If you run with ansible -i inventory ..., it won't find the group_vars file (it will only find it when running e.g. ansible -i inventory/prod/prod1).
Consider a layout like this:
inventory/
├── group_vars
│   ├── prod1.yaml
│   ├── prod2.yaml
│   └── prod3.yaml
└── prod
├── prod1.yaml
├── prod2.yaml
└── prod3.yaml
Where each inventory file places hosts into a similarly named hostgroup. E.g., inventory/prod/prod1.yaml contains:
all:
children:
prod1:
hosts:
prod1-node0:
prod1-node1:
prod1-node2:
If we have a variable defined with a different value for each group:
$ grep . inventory/group_vars/*
inventory/group_vars/prod1.yaml:location: datacenter1
inventory/group_vars/prod2.yaml:location: datacenter2
inventory/group_vars/prod3.yaml:location: datacenter3
And a playbook like this:
- hosts: all
gather_facts: false
tasks:
- debug:
var: location
We can run it against all the hosts (I'm only using two groups here, prod1 and prod2, in order to keep the output shorter):
$ ansible-playbook playbook.yaml -i inventory
TASK [debug] ********************************************************************************************
ok: [prod1-node0] => {
"location": "datacenter1"
}
ok: [prod1-node1] => {
"location": "datacenter1"
}
ok: [prod1-node2] => {
"location": "datacenter1"
}
ok: [prod2-node0] => {
"location": "datacenter2"
}
ok: [prod2-node1] => {
"location": "datacenter2"
}
ok: [prod2-node2] => {
"location": "datacenter2"
}
Or you can run the playbook against a specific group:
$ ansible-playbook playbook.yaml -i inventory -l prod2
TASK [debug] ********************************************************************************************
ok: [prod2-node0] => {
"location": "datacenter2"
}
ok: [prod2-node1] => {
"location": "datacenter2"
}
ok: [prod2-node2] => {
"location": "datacenter2"
}
In each case, hosts will use the values from the appropriate group_vars file based on their hostgroup.