實例–debug

1. 將 lvfs2.yml 腳本的 hosts 改為 balancers，並存成 lvfs3.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 lvfs3.yml
   ---
   - hosts: balancers 
     tasks:
     ......................    
     - debug:
         msg: Volume group does not exist
       when: ansible_lvm.vgs.fieldwork is undefined
   

2. ansible-playbook 執行 lvfs3.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 lvfs3.yml
   
   PLAY [balancers] ***************************************************************
   
   TASK [Gathering Facts] *********************************************************
   ok: [kvm15]
   
   TASK [Create a logical volume of 200m] *****************************************
   skipping: [kvm15]
   
   TASK [Create a ext4] ***********************************************************
   skipping: [kvm15]
   
   TASK [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