Ansible Playbook执行报错：hosts字段缺失与变量加载异常求助

问题1：第一个Playbook执行报错 ERROR! the field 'hosts' is required but was not set #

原Playbook中第一个条目：

- name: Configure System for Oracle 19
  vars_prompt:
    - name: setup_test
      prompt: "Configure System for Test or Production? [Test/Prod]: "
      default: Test
      private: no

  vars_files:
    - /etc/ansible/roles/oracle_19_test/defaults/main.yml

这是一个不完整的Play——Ansible要求每个Play必须包含hosts字段，即使只是用来获取变量或执行本地操作，也需要指定目标主机（比如localhost）。

修复方案 #

将变量配置整合到一个完整的本地Play中（仅用于获取变量，不执行远程操作）：

---
# 全局变量与提示，仅在本地执行，不收集主机信息
- hosts: localhost
  gather_facts: no
  vars_prompt:
    - name: setup_test
      prompt: "Configure System for Test or Production? [Test/Prod]: "
      default: Test
      private: no
  vars_files:
    - /etc/ansible/roles/oracle_19_test/defaults/main.yml

# 配置Appserver的Play
- hosts: "{{ Appserver_STBY }}"
  tasks:
  - name: tnsnames auf Appserver anpassen
    template:
      src: tnsnames_Appserver.ora.j2
      dest: /opt/oracle/app/oracle/product/11.2.0/client_1/network/admin/tnsnames.ora
      owner: oracle
      group: oinstall
      mode: 0644
      backup: yes

# 配置Floorserver的Play
- hosts: "{{ Floorserver }}"
  tasks:
  - name: tnsnames auf Floorserver anpassen
    template:
      src: /etc/ansible/roles/oracle_19_test/templates/tnsnames_Floor.ora.j2
      dest: /u01/app/oracle/product/11.2.0/xe/network/admin/tnsnames.ora
      owner: oracle
      group: oinstall
      mode: 0644
      backup: yes
    tags: floortest

问题2：自动加载group_vars/all时变量未定义 ERROR! The field 'hosts' has an invalid value, which includes an undefined variable. The error was: 'Floorserver' is undefined #

错误原因 #

Ansible自动加载group_vars/all的前提是：

• group_vars目录必须和你指定的inventory文件/目录处于同一级路径下
• 执行Playbook时，要么工作目录是inventory所在目录，要么通过-i参数明确指定inventory路径

如果Ansible找不到对应的group_vars目录，就无法加载其中的变量，导致Floorserver未定义。

修复方案 #

方案1：执行Playbook时指定正确的inventory路径

假设你的inventory文件是/etc/ansible/hosts，且group_vars目录在/etc/ansible/下，执行命令时：

ansible-playbook -i /etc/ansible/hosts your_playbook.yml

方案2：在ansible.cfg中配置默认inventory路径

编辑/etc/ansible/ansible.cfg，确保以下配置正确：

[defaults]
inventory = /etc/ansible/hosts

这样执行Playbook时无需手动指定-i参数，Ansible会自动加载对应路径下的group_vars。

方案3：在Playbook中显式加载vars_files（已验证可行）

保持手动加载的方式，确保变量被正确导入：

- hosts: "{{ Floorserver }}"
  vars_files:
    - /etc/ansible/group_vars/all
  tasks:
  - name: tnsnames auf Floorserver anpassen
    template:
      src: /etc/ansible/roles/oracle_19_test/templates/tnsnames_floor.ora.j2
      dest: /u01/app/oracle/product/11.2.0/xe/network/admin/tnsnames.ora
      owner: oracle
      group: oinstall
      mode: 0644
      backup: yes
    tags: floortest

内容的提问来源于stack exchange，提问作者Luke