How to collect selective dsks and unused space using ansible facts?

Question

Here are my example codes, questions at bottom

hw.j2:

System Total Memory     : {{ ansible_memtotal_mb }}
Free Memory             : {{ ansible_memfree_mb }}
System Total CPU        : {{ ansible_processor_cores }}
System Virtual CPU      : {{ ansible_processor_vcpus }}

Disks capacities
        /dev/sda        : {{ ansible_devices.sda.size }}
        /dev/sdb        : {{ ansible_devices.sdb.size }}
        /dev/sdc        : {{ ansible_devices.sdc.size }}

collecthw.yml:

---
- name: Collect information
  become: yes
  hosts: clients

  tasks:
  - name: use template from labs/hw.j2
    template:
      src: hw.j2
      dest: hw.{{ ansible_facts.hostname }}.txt
      owner: corona
      group: corona
      mode: '0600'

It works okay but ..

Now my questions are:

1. How to loop across all /dev/sd* in managed nodes and collect their respective disk size?
2. This is the disk size, how about unused disk space in the disk?

Thank you in advance for those that able to spend time and effort in getting the answer or perhaps other advice. Newbie here xD

Answer 1

For example, select all devices except loop* and display size

    - set_fact:
        my_devices: "{{ ansible_devices.keys()|
                        reject('match', '^loop(.*)$')|
                        list }}"
    - debug:
        msg: "{{ item }} {{ ansible_devices[item].size }}"
      loop: "{{ my_devices }}"

give

  msg: nvme0n1 238.47 GB

Q1: "How to loop across all /dev/sd* in managed nodes and collect their respective disk size?"

A1: In the code above, change the reject filter to select

                        select('match', '^sd(.*)$')|

and use the template below

{% for dev in my_devices %}
{{ dev }}: {{ ansible_devices[dev].size }}
{% endfor %}

---

Q2: "How about unused disk space in the disk?"

A2: Use the variable ansible_mounts to display unsused space. For example

    - set_fact:
        my_devs: "{{ my_devs|default([]) +
                     [ansible_mounts|
                      selectattr('device', 'match', my_regex)|
                      list|
                      json_query(my_query)]|first }}"
      loop: "{{ my_devices }}"
      vars:
        my_regex: '^(.*){{ item }}(.*)$'
        my_query: '[].[device, size_total, size_available]'

    - debug:
        msg: "dev: {{ item.0 }}
              size[MB]: {{ (item.1|int / 1000000)|int }}
              free[MB]: {{ (item.2|int / 1000000)|int }}"
      loop: "{{ my_devs }}"

give

  msg: 'dev: /dev/nvme0n1p6 size[MB]: 41015 free[MB]: 12677'
  msg: 'dev: /dev/nvme0n1p7 size[MB]: 109899 free[MB]: 39896'
  msg: 'dev: /dev/nvme0n1p2 size[MB]: 100 free[MB]: 45'

Use the template below to store unused space in Bytes

{% for dev in my_devs %}
{{ dev[0] }}: {{ dev[2] }}
{% endfor %}

Answer 2

Ok gys I finally found out the answer . Its default value with jinja template.
Example code below:
vi hw.j2
Disks capacities
/dev/sda : {{ ansible_devices.sda.size|default("NONE", true) }}
/dev/sdb : {{ ansible_devices.sdb.size|default("NONE", true) }}
/dev/sdc : {{ ansible_devices.sdc.size|default("NONE", true) }}
/dev/sdz : {{ ansible_devices.sdz.size|default("NONE", true) }

client@ cat list-hw.r8s2.txt
Disks capacities
/dev/sda : 20.00 GB
/dev/sdb : 20.00 GB
/dev/sdc : 20.00 GB
/dev/sdz : NONE