【自动化运维神器Ansible】Ansible常用模块之hostname模块详解

• Ansible将模块代码传输到目标节点
• 在目标节点上执行模块代码
• 收集执行结果并返回控制节点
• 根据结果决定后续操作（如notify handlers）

• hostname模块提供了多个参数来满足不同场景的需求：

• 查看当前主机名：

- name: 获取当前主机名
  hosts: all
  tasks:
    - name: 显示主机名
      ansible.builtin.hostname:
      register: result
    - debug: var=result.ansible_facts.hostname

• 永久修改主机名：

- name: 修改服务器主机名
  hosts: web_servers
  become: yes
  tasks:
    - name: 设置永久主机名
      ansible.builtin.hostname:
        name: web01

• 条件性修改主机名：

- name: 仅当当前主机名不匹配时修改
  hosts: all
  become: yes
  tasks:
    - name: 检查并设置主机名
      ansible.builtin.hostname:
        name: "{{ new_hostname }}"
      when: ansible_hostname != new_hostname

• 临时修改主机名：

- name: 临时修改测试环境主机名
  hosts: test_servers
  tasks:
    - name: 设置临时主机名
      ansible.builtin.hostname:
        name: temp-test-node
        permanent: no

- name: 跨平台主机名设置
  hosts: mixed_servers
  become: yes
  tasks:
    - name: 设置统一主机名
      ansible.builtin.hostname:
        name: "{{ common_hostname }}"
        use: "{{ 'hostnamectl' if ansible_service_mgr == 'systemd' else 'sysctl' }}"

• 问题1：权限不足

ERROR! Failed to set hostname: You need to be root to change the host name

• 问题2：无效主机名

Invalid hostname: contains uppercase letters

- name: 完整主机名配置
  hosts: all
  become: yes
  tasks:
    - name: 设置主机名
      ansible.builtin.hostname:
        name: "{{ new_hostname }}"
    
    - name: 更新/etc/hosts
      ansible.builtin.lineinfile:
        path: /etc/hosts
        regexp: '.*{{ ansible_default_ipv4.address }}.*'
        line: "{{ ansible_default_ipv4.address }} {{ new_hostname }}"
        state: present

- name: 修改主机名并重启相关服务
  hosts: critical_servers
  become: yes
  tasks:
    - name: 设置新主机名
      ansible.builtin.hostname:
        name: "{{ new_hostname }}"
      notify: restart services
  
  handlers:
    - name: restart services
      ansible.builtin.service:
        name: "{{ item }}"
        state: restarted
      loop:
        - sshd
        - rsyslog
        - cron

• 批处理模式：

- name: 批量修改主机名
  hosts: "{{ target_group }}"
  serial: 20  # 每次处理20台
  tasks:
    - name: 设置主机名
      ansible.builtin.hostname:
        name: "{{ inventory_hostname }}"

• 并行执行：

ansible-playbook -f 20 hostname_change.yml

• 敏感信息保护：
  • 使用Ansible Vault加密包含敏感信息的变量
  • 避免在playbook中硬编码主机名

• 审计跟踪：

- name: 记录主机名变更
  ansible.builtin.lineinfile:
    path: /var/log/hostname_changes.log
    line: "{{ ansible_date_time.iso8601 }}: Changed from {{ ansible_hostname }} to {{ new_hostname }}"
    create: yes