Show disk space and warn about disk full in Ansible

Ansible Disk Check

* Shows a message while asserting like: 

ok: [host] => {                  
    "msg": "disk usage 4.2B of total 20.0GB (21.0%) (should be within limit 90.0%)"
}

* Note this only looks at first mount point on current node
* Fails if disk is near-full
* Last step pushes to a push-based monitoring service, which will alert us if it doesn't get there after some time
* Need to setup a  variable `disk_limit`, which is the max acceptable usage ratio, e.g. set it to 0.8 if you want to keep disks within 80% of max size

check.yml

- set_fact:                                                                                                             
    mount: "{{ ansible_mounts | first }}"                                                                               
                                                                                                                        
- set_fact: disk_usage="{{ mount.size_total - mount.size_available }}"                                                  
- set_fact: disk_usage_ratio="{{ (disk_usage|float) / mount.size_total }}"                                              
- set_fact: disk_usage_s="{{ (disk_usage|float / 1000000000) | round(1, 'common') }}GB"                                 
- set_fact: disk_total_s="{{ (mount.size_total / 1000000000) | round(1, 'common') }}GB"                                 
- set_fact: disk_usage_ratio_s="{{ (100 * (disk_usage_ratio|float)) | round(1, 'common') }}%"                           
- set_fact: disk_limit_ratio_s="{{ (100 * disk_limit|float) |round }}%"                                                 
                                                                                                                        
- debug:                                                                                                                
    msg: "disk usage {{ disk_usage_s }} of total {{ disk_total_s }} ({{ disk_usage_ratio_s }}) (should be within limit {{ disk_limit_ratio_s }})"
                                                                                                                        
- name:                                                                                                                 
  assert:                                                                                                               
    that: ( (disk_usage|float)/mount.size_total ) < disk_limit|float                                                    
    msg: "Disk usage {{ disk_usage_ratio_s }} exceeds {{ disk_limit_ratio_s }}"
  any_errors_fatal: true
                                                                                                                        
- name: indicate disks okay to statuscake
  local_action: command /usr/bin/wget 'https://push.statuscake.com/?PK=abcdefghi&TestID=123456&time=0'
  run_once: true