實例–debug

1. 將 blklvfs2.yml 腳本的 hosts 改為 blancers，並存成 blklvfs3.yml。

   [deyu1@kvm19 ansible]$ vim blklvfs3.yml
   [deyu1@kvm19 ansible]$ grep hosts blklvfs3.yml
   - hosts: balancers
   

2. blklvfs3.yml，增加 debug 除錯，當 vg fieldwork 不存在時印出客製化訊息 "Volume group does not exist"。

   [deyu1@kvm19 ansible]$ cat blklvfs3.yml
   ---
   - hosts: balancers 
     tasks:
     ......................    
     - ansible.builtin.debug:
         msg: Volume group does not exist
       when: ansible_lvm.vgs.fieldwork is undefined
   

3. ansible-playbook 執行 blklvfs3.yml 腳本，因 kvm15 的 vg fieldwork 不存在，所以執行 debug 任務，列印客製化訊息 "Volume group does not exist"。

   [deyu1@kvm19 ansible]$ ansible-playbook blklvfs3.yml
   
   PLAY [balancers] ****************************************************************
   
   TASK [Gathering Facts] **********************************************************
   ok: [kvm15]
   
   TASK [Create a logical volume of 200m] ******************************************
   skipping: [kvm15]
   
   TASK [Create a ext4] ************************************************************
   skipping: [kvm15]
   
   TASK [ansible.builtin.debug] ****************************************************
   ok: [kvm15] => {
       "msg": "Volume group does not exist"
   }
   
   PLAY RECAP **********************************************************************
   kvm15 : ok=2  changed=0  unreachable=0  failed=0  skipped=2  rescued=0  ignored=0