Ansible: Retrieve Data from inventory - ansible

Question

I need to retrieve the IP of bob_server from the inventory file. I am not clear as to what combination to use in filter, lookup, and when? Depending on the inventory filebob_server and alice_server names can change, but app_type won't change. My playbook logic is obviously wrong, Can someone guide me the correct way to fetch IP address when app_type = bob
My current Inventory file:
---
all:
hosts:
children:
bob_server:
hosts: 10.192.2.6
vars:
app_type: bob
alice_server:
hosts: 10.192.2.53
vars:
app_type: alice
My Playbook
---
- hosts: localhost
name: Retrive data
tasks:
- name: Set Ambari IP
set_fact:
ambariIP: "{{ lookup('hosts', children) }}"
when: "hostvars[app_type] == 'bob'"

Answer 1

Given the inventory
shell> cat hosts-01
---
all:
hosts:
children:
bob_server:
hosts: 10.192.2.6
vars:
app_type: bob
alice_server:
hosts: 10.192.2.53
vars:
app_type: alice
The simple option is using ansible-inventory, e.g.
- hosts: localhost
tasks:
- command: ansible-inventory -i hosts-01 --list
register: result
- set_fact:
my_inventory: "{{ result.stdout|from_yaml }}"
- debug:
var: my_inventory.bob_server.hosts
gives
my_inventory.bob_server.hosts:
- 10.192.2.6
If you want to parse the file on your own read it into a dictionary and flatten the paths, e.g. (install ansible.utils ansible-galaxy collection install ansible.utils)
- include_vars:
file: hosts-01
name: my_hosts
- set_fact:
my_paths: "{{ lookup('ansible.utils.to_paths', my_hosts) }}"
- debug:
var: my_paths
gives
my_paths:
all.children.alice_server.hosts: 10.192.2.53
all.children.alice_server.vars.app_type: alice
all.children.bob_server.hosts: 10.192.2.6
all.children.bob_server.vars.app_type: bob
all.hosts: null
Now select the keys ending bob_server.hosts
- set_fact:
bob_server_hosts: "{{ my_paths|
dict2items|
selectattr('key', 'match', '^.*bob_server\\.hosts$')|
items2dict }}"
gives
bob_server_hosts:
all.children.bob_server.hosts: 10.192.2.6
and select the IPs
- set_fact:
bob_server_ips: "{{ bob_server_hosts.values()|list }}"
gives
bob_server_ips:
- 10.192.2.6
The inventory is missing the concept of groups. See Inventory basics: formats, hosts, and groups. Usually, the value of children is a group of hosts. In this inventory, the value of children is the single host. This is conceptually wrong but still valid, .e.g
- hosts: bob_server
gather_facts: false
tasks:
- debug:
var: inventory_hostname
gives
shell> ansible-playbook -i hosts-01 playbook.ym
...
TASK [debug] ****************************************************
ok: [10.192.2.6] =>
inventory_hostname: 10.192.2.6