[メモ][Ansible] フィルタでIPからDNS逆引き用アドレスを生成

- name: Test Playbook  
  hosts: localhost
  tasks:
  - name: Set
    set_fact:
     test_num: 3
     test_network: "10.8.30.1"

  - debug:
     msg: "{{ test_network.split('.')[:-test_num:-1] | join('.') }}"

• 実行結果

TASK [debug] ********************************************************************************************
ok: [localhost] => {
    "msg": "1.30"
}