Create Dictionary from Ansible inventory file - ansible

Question

I am trying to create a dictionary with below ansible inventory file.
"myfile": {
"all": {
"hosts": null,
"vars": {
"ansible_connection": "local",
"ansible_python_interpreter": "{{ ansible_playbook_python }}"
}
},
"USA": {
"children": {
"MYDC1": {
"children": {
"MYDC1-CLU01": {
"hosts": {
"MYDC2-VM1": null,
"MYDC2-VM2": null,
"MYDC2-VM3": null,
"MYDC2-VM4": null,
"MYDC2-VM5": null,
"MYDC2-VM6": null
}
}
}
},
"MYDC2": {
"children": {
"MYDC2-CLU01": {
"hosts": {
"MYDC1-VM1": null
"MYDC1-VM2": null
}
}
}
},
"MYDC3": {
"children": {
"MYDC3-CLU01": {
"hosts": {
"MYDC3-VM1": null
"MYDC3-VM2": null
"MYDC3-VM3": null
}
}
}
}
},
"vars": {
"vcenter_hostname": "myvcenter.esxihost.com"
}
}
}
}
From this file, expected output is:
{
'MYDC1-CLU01': ['MYDC1-VM1.myhost.com','MYDC1-VM2.myhost.com'],
'MYDC2-CLU01':['MYDC2-VM1.myhost.com','MYDC2-VM2.myhost.com','MYDC2-VM3.myhost.com','MYDC2-VM4.myhost.com','MYDC2-VM5.myhost.com','MYDC2-VM6.myhost.com'],
'MYDC3-CLU01':['MYDC3-VM1.myhost.com','MYDC3-VM2.myhost.com','MYDC3-VM3.myhost.com'],
}
The code given below works fine:
my_domain: myhost.com
my_groups: [MYDC1-CLU01, MYDC2-CLU01, MYDC3-CLU01]
cluster_dict: "{{ dict(my_groups|
zip(my_groups|
map('extract', groups)|
map('product', [my_domain])|
map('map', 'join', '.')|
list)) }}"
Output:
$ ansible-playbook main.yml -i hosts.yml
[WARNING]: Invalid characters were found in group names but not replaced, use -vvvv to see details
PLAY [Check Service status] ***********************************************************************************************************************************************************************************************
TASK [Gathering Facts] ****************************************************************************************************************************************************************************************************ok: [localhost]
TASK [my_checks : Show host inventory file] *************************************************************************************************************************************************************************ok: [localhost] => {
"cluster_dict": {
"MYDC1-CLU01": [
"MYDC1-VM1.myhost.com",
"MYDC1-VM2.myhost.com"
],
"MYDC2-CLU01": [
"MYDC2-VM1.myhost.com",
"MYDC2-VM2.myhost.com",
"MYDC2-VM3.myhost.com",
"MYDC2-VM4.myhost.com",
"MYDC2-VM5.myhost.com",
"MYDC2-VM6.myhost.com"
],
"MYDC3-CLU01": [
"MYDC3-VM1.myhost.com",
"MYDC3-VM2.myhost.com"
]
}
}
I have 2 questions:
1: Is there anyway I can store variable in "cluster_dict" without passing the hosts.yml file in the command line. Like converting hosts file into below
host_intent_data: "{{ lookup('file', 'hosts.yml')|from_yaml }}"
and process the host_intent_data.
The CLUSTER/DC values will be growing each day and we can't use static fields as mentioned in my_groups.Is there any way we can get the desired dictionary dynamically?

Answer 1

Given the inventory
shell> cat hosts
all:
hosts:
vars:
ansible_connection: local
ansible_python_interpreter: '{{ ansible_playbook_python }}'
USA:
children:
MYDC1:
children:
MYDC_CLU01:
hosts:
MYDC1-VM1:
MYDC1-VM2:
MYDC2:
children:
MYDC2_CLU01:
hosts:
MYDC2-VM1:
MYDC2-VM2:
MYDC2-VM3:
MYDC2-VM4:
MYDC2-VM5:
MYDC2-VM6:
vars:
vcenter_hostname: myvcenter.esxihost.com
and the variables
my_domain: myhost.com
my_groups: [MYDC_CLU01, MYDC2_CLU01]
Put the below declaration into the vars
my_dict: "{{ dict(my_groups|
zip(my_groups|
map('extract', groups)|
map('product', [my_domain])|
map('map', 'join', '.')|
list)) }}"
gives what you want
my_dict:
MYDC2_CLU01:
- MYDC2-VM1.myhost.com
- MYDC2-VM2.myhost.com
- MYDC2-VM3.myhost.com
- MYDC2-VM4.myhost.com
- MYDC2-VM5.myhost.com
- MYDC2-VM6.myhost.com
MYDC_CLU01:
- MYDC1-VM1.myhost.com
- MYDC1-VM2.myhost.com
Example of a complete playbook for testing
- hosts: all
gather_facts: false
vars:
my_domain: myhost.com
my_groups: [MYDC_CLU01, MYDC2_CLU01]
my_dict: "{{ dict(my_groups|
zip(my_groups|
map('extract', groups)|
map('product', [my_domain])|
map('map', 'join', '.')|
list)) }}"
tasks:
- debug:
var: my_dict
run_once: true
Q: "Convert hosts file to 'cluster_dict'."
A: Use ansible-inventory and convert the file to yaml. Select the region (e.g. USA) and create the dictionary. For example, if you provide a valid inventory file
cluster: "{{ lookup('pipe', 'ansible-inventory -i hosts.json --list --yaml')|from_yaml }}"
cluster_USA: "{{ cluster.all.children.USA.children|json_query('*.children') }}"
cluster_dict_raw: |
{% for i in cluster_USA %}
{{ i.keys()|first }}:
{{ (i.values()|first).hosts.keys() }}
{% endfor %}
cluster_dict: "{{ cluster_dict_raw|from_yaml }}"
gives
cluster_dict:
MYDC1-CLU01: [MYDC2-VM1, MYDC2-VM2, MYDC2-VM3, MYDC2-VM4, MYDC2-VM5, MYDC2-VM6]
MYDC2-CLU01: [MYDC1-VM1, MYDC1-VM2]
MYDC3-CLU01: [MYDC3-VM1, MYDC3-VM2, MYDC3-VM3]
Notes:
Test the inventory file before complaining!
shell> ansible-inventory -i hosts.json --list --yaml
The names of the groups are not valid. You must have seen the warning. Fix it before complaining!
[WARNING]: Invalid characters were found in group names ...
Fit the template to your needs. For example, add domain and create FQDN
cluster_dict_raw: |
{% for i in cluster_USA %}
{{ i.keys()|first }}:
{{ (i.values()|first).hosts.keys()|product(['myhost.com'])|
map('join', '.')|list }}
{% endfor %}