issue in counting no. of host in inventory ?

[Gurminder Singh]

I wrote a playbook to count number of host in inventory, can someone look or suggest better way of achieving this task, this play gives error in compling stage itself, however when I check the syntax in http://codebeautify.org/yaml-validator this shows it is valid.

Please add your comment and suggestions ?

My Playbook

---

- name: Host Entry in Inventory

  hosts: "ios_switches"

  gather_facts: no

  connection: local

  task:

  - name: Host Count

       vars:

          num_hosts: "{{ groups['ios_switches'] | length }}"

Error I get after running playbook

ERROR! 'task' is not a valid attribute for a Play

The error appears to have been in '/home/gurmisin/ansible/host_count.yml': line 2, column 3, but may

be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

---

- name: Host Entry in Inventory

  ^ here

[Brian Coca]

you have no action in that task, guessing you want:

- name: Host Count
debug:
msg: "{{ groups['ios_switches'] | length }}"


----------
Brian Coca

[Kai Stian Olstad]

On 16. mai 2017 20:23, Gurminder Singh wrote:
> I wrote a playbook to count number of host in inventory, can someone look
> or suggest better way of achieving this task, this play gives error in
> compling stage itself, however when I check the syntax in
> http://codebeautify.org/yaml-validator this shows it is valid.
>
> Please add your comment and suggestions ?
>

> *My Playbook*

> ---
> - name: Host Entry in Inventory
> hosts: "ios_switches"
> gather_facts: no
> connection: local
>
> task:
> - name: Host Count
> vars:
> num_hosts: "{{ groups['ios_switches'] | length }}"
>

> *Error I get after running playbook*

>
> ERROR! 'task' is not a valid attribute for a Play

It tasks and not task.

--
Kai Stian Olstad

[Gurminder Singh]

Thank You Kai,

I corrected that and made some more changes to my playbook which eventually worked. We can also use 

debug:

       msg: "Host count: {{ ansible_play_hosts | length }}"

- _ansible_play_hosts_ is an Ansible-defined variable which is a list of the hosts in the current play, i.e. what the above pattern matches

- **run_once** ensures we don't run the debug command for every single host in the list, which would be a big waste of time

---

- name: Host Count In Inventory

  hosts: ios

  gather_facts: no

  connection: local

  tasks:

    - name: Host Count

      run_once: true

      debug:

         msg: "Host Count: {{ groups['ios'] | length }}"

[Brian Coca]

or just run on localhost

- name: Host Count In Inventory

hosts: localhost
gather_facts: no

tasks:

- name: Host Count

debug:
msg: "Host Count: {{ groups['ios'] | length }}"

alternatively:

ansible ios --list-hosts|head -n 1
----------
Brian Coca