Ansible单文件多blockinfile任务with when失效及语法告警求助

问题根源 #

你把多个blockinfile任务和对应的when条件写在了同一个Ansible任务条目下，而YAML字典要求键必须唯一。Ansible解析时会直接忽略前面的重复键，只保留最后一个定义的blockinfile和when配置——这就是为什么满足第一个条件的任务没输出、只有最后一个任务生效，同时触发重复键语法告警的原因。单个任务正常是因为没有重复键，多任务写在一起就违反了YAML的字典键唯一性规则。

修正后的代码示例 #

方式1：拆分为独立任务（共享变量） #

把变量提取到单独的任务或play级别，每个blockinfile作为独立任务存在：

- name: define shared variables
  vars:
    username: testuser
    envname1: user1
    envname2: user2

- name: add envname1 block to /tmp/fileout
  blockinfile:
    marker: "#--------------{mark}--------------------envname1"
    path: /tmp/fileout
    block: |
      " ###########################################################"
      You have been logging into  {{ envname1 }} environment.
      System Name - {{ username }}
      IP address - {{ ansible_facts['default_ipv4']['address']}}
      "############################################################"
  when: ansible_facts['default_ipv4']['network'] == '10.45.122.0'

- name: add envname2 block to /tmp/fileout
  blockinfile:
    marker: "#------------- {mark}----------------------- envname2"
    path: /tmp/fileout
    block: |
      " ###########################################################"
      You have been logging into  {{ envname2 }} environment.
      System Name - {{ username }}
      IP address - {{ ansible_facts['default_ipv4']['address']}}
      "############################################################"
  when: ansible_facts['default_ipv4']['network'] == '10.46.122.0'

方式2：用block包裹共享变量的任务 #

如果希望变量只在这组任务内生效，用block来包裹多个任务，共享变量：

- name: manage user output blocks
  vars:
    username: testuser
    envname1: user1
    envname2: user2
  block:
    - name: add envname1 block to /tmp/fileout
      blockinfile:
        marker: "#--------------{mark}--------------------envname1"
        path: /tmp/fileout
        block: |
          " ###########################################################"
          You have been logging into  {{ envname1 }} environment.
          System Name - {{ username }}
          IP address - {{ ansible_facts['default_ipv4']['address']}}
          "############################################################"
      when: ansible_facts['default_ipv4']['network'] == '10.45.122.0'

    - name: add envname2 block to /tmp/fileout
      blockinfile:
        marker: "#------------- {mark}----------------------- envname2"
        path: /tmp/fileout
        block: |
          " ###########################################################"
          You have been logging into  {{ envname2 }} environment.
          System Name - {{ username }}
          IP address - {{ ansible_facts['default_ipv4']['address']}}
          "############################################################"
      when: ansible_facts['default_ipv4']['network'] == '10.46.122.0'

效果说明 #

修正后，每个blockinfile都是独立的任务，YAML解析不会再出现重复键问题。Ansible会分别判断每个任务的when条件，匹配对应网络的任务会正常执行，将对应内容写入目标文件。

内容的提问来源于stack exchange，提问作者chamara