Ansible variable interpolation not working in brackets

Question

I'm using Ansible to grab an VIP from InfoBlox and running into an issue when trying to build my exclude list. I need to exclude the first 3 IP's as they are reserved, however the CIDR range is a dynamic variable so I need to build this exclude list on the fly. Here's a representation of what I have so far:

---
- name: Assign VIP to FQDN in Grid Manager
  hosts: all
  connection: local
  gather_facts: false

  vars:
    CIDR: 10.0.0.

  tasks:

  - set_fact:
      EXCLUDES: "{{ EXCLUDES | default([]) + [item] }}"
    with_sequence: start=1 end=3 format=''{{ CIDR }}%d''

  - set_fact:
      formated_excludes: "{{ EXCLUDES |join(', ') }}"

  - debug:
      msg: "{{ formated_excludes }}"

  - set_fact:
      VIP:  "{{ lookup('nios_next_ip', '10.0.0.0/25', exclude=[formated_excludes]) | first }}"

  - name: Print next IP address
    debug:
      msg: "The next available IP is {{ VIP }}"

Here are the results of the play:

PLAY [Assign VIP to FQDN in Grid Manager] *****************************************************************************************************************

TASK [set_fact] *******************************************************************************************************************************************
ok: [localhost] => (item='10.0.0.1')
ok: [localhost] => (item='10.0.0.2')
ok: [localhost] => (item='10.0.0.3')

TASK [set_fact] *******************************************************************************************************************************************
ok: [localhost]

TASK [debug] **********************************************************************************************************************************************
ok: [localhost] => {
    "msg": "'10.0.0.1', '10.0.0.2', '10.0.0.3'"
}

TASK [set_fact] *******************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"msg": "An unhandled exception occurred while running the lookup plugin 'nios_next_ip'. Error was a <class 'ansible.errors.AnsibleError'>, original message: Invalid value for exclude: \"'10.0.0.1', '10.0.0.2', '10.0.0.3'\": Invalid IPv4 address"}

PLAY RECAP ************************************************************************************************************************************************
localhost                  : ok=3    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

The formatting appears to be fine, however the lookup won't accept it. For comparison, using the following works fine:

  - set_fact:
      VIP:  "{{ lookup('nios_next_ip', '10.0.0.0/25', exclude=['10.0.0.1', '10.0.0.2', '10.0.0.3']) | first }}"

Here are the results:

PLAY [Assign VIP to FQDN in Grid Manager] *****************************************************************************************************************

TASK [set_fact] *******************************************************************************************************************************************
ok: [localhost]

TASK [Print next IP address] ******************************************************************************************************************************
ok: [localhost] => {
    "msg": "The next available IP is 10.0.0.4"
}

PLAY RECAP ************************************************************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Any thoughts on why this variable isn't working would be much appreciated!

Answer 1

Parameter exclude is "List of IP's ...", but the filter join makes a string from the list

- set_fact:
    formated_excludes: "{{ EXCLUDES |join(', ') }}"

Use the list EXCLUDES in the parameter

- set_fact:
    VIP:  "{{ lookup('nios_next_ip', '10.0.0.0/25', exclude=EXCLUDES) | first }}"