Ansible中rescue段未执行排查：为何未创建800MiB逻辑卷

你的rescue段未执行的核心原因是：Ansible的rescue仅在对应block内有任务执行失败时才会触发，而你当前block里的两个任务都只是被跳过，并未产生失败。

具体细节：

• 第一个debug任务：when: ansible_lvm.vgs.research is not defined，但你的节点已定义该卷组，条件不满足，任务直接跳过，无失败。
• 第二个lvol任务：when: ansible_lvm.vgs.research is defined and ansible_lvm.vgs.research.size_g > '1500 MiB'，你的节点空间低于1500MiB，条件不满足，任务同样跳过，无失败。

整个block没有任务抛出失败，rescue自然不会启动。

修正方案 #

你不需要依赖block/rescue实现这个逻辑，直接用条件分支处理两种空间情况即可，这种方式更清晰直观：

---
- name: Criar lvm no sistema
  hosts: all
  become: true
  tasks:
    - name: Verificar se existe o volume group RESEARCH
      ansible.builtin.debug:
        msg: "O grupo de volume RESEARCH não existe"
      when: ansible_lvm.vgs.research is not defined

    - name: Criar logical volume de 1500 MiB (空间充足时)
      community.general.lvol:
        vg: research
        lv: data
        size: 1500m
      when: ansible_lvm.vgs.research is defined and ansible_lvm.vgs.research.size_g > '1500 MiB'

    - name: Criar logical volume de 800 MiB (空间不足时)
      community.general.lvol:
        vg: research
        lv: data
        size: 800m
      when: ansible_lvm.vgs.research is defined and ansible_lvm.vgs.research.size_g < '1500 MiB'

如果非要用block/rescue的话，需要让block内的lvol任务在空间不足时强制执行并失败，触发rescue：

---
- name: Criar lvm no sistema
  hosts: all
  become: true
  tasks:
    - name: Verificar e criar lvm no volume group RESEARCH
      block:
        - name: Se o grupo de volume não existir, uma mensagem de alerta será dada
          ansible.builtin.debug:
            msg: "O grupo de volume RESEARCH não existe"
          when: ansible_lvm.vgs.research is not defined

        - name: Tentar criar logical volume de 1500 MiB
          community.general.lvol:
            vg: research
            lv: data
            size: 1500m
          when: ansible_lvm.vgs.research is defined
      rescue:
        - name: Criar logical volume de 800 MiB (空间不足时触发)
          community.general.lvol:
            vg: research
            lv: data
            size: 800m
          when: ansible_lvm.vgs.research is defined

注：第二种方式依赖lvol模块在空间不足时返回失败状态，这符合模块的预期行为——当无法满足指定大小的创建请求时，模块会抛出失败。

内容的提问来源于stack exchange，提问作者Felipe