Ansible and hardware checks

Question

I have to check different hardware and configurations elements on Linux machines using ansible, and I am not sure at all about how to do it (RAM, disk space, DNS, CPU...), I've understood that I can find nearly all I want in the ansible facts, but I do not understand how I can use it.

For example, I have to check if the RAM amount is at least of 4GB and have an alarm if not, so I tried many things, and... nothing works.

Here is an example of what I tried.

 - hosts: client
   remote_user: user

  tasks:
      - debug: var=ansible_memory_mb
      - debug: msg="total RAM is {{ ansible_memory_mb.real.total }}"
      - fail: msg="not enough RAM"t
      - when: {{ ansible_memory_mb.real.total }} < 4096

Could you tell me how it works ? and maybe there is a better way to do what I want using Ansible ?

Thank you for your answer.

Answer 1

There are a few things wrong with the snippet you posted.

• Your indentation is off. tasks needs to be at the same indentation level as hosts.

• The when condition needs to be part of the fail task block, not a separate list item.

• In general, you do not need to use {{ ... }} in a when condition, the entire expression will be treated as a Jinja template.

Try this:

- hosts: client
  remote_user: user
  tasks:
    - debug: var=ansible_memory_mb
    - debug: msg="total RAM is {{ ansible_memory_mb.real.total }}"
    - fail: msg="not enough RAM"
      when: ansible_memory_mb.real.total < 4096

You can also use the assert module to check a condition or list of conditions.

- assert:
    that:
      - ansible_memory_mb.real.total >= 4096
      - some other condition
      - ...