【自动化运维神器Ansible】playbook案例解析：Tags组件实现任务选择性执行

• 语法规则：

- name: task_name
  module: parameters
  tags:
    - tag1
    - tag2

---
# tags example
- hosts: websrvs
  remote_user: root
  gather_facts: no
  tasks:
    - name: Install httpd
      yum: name=httpd state=present
    
    - name: Install configure file
      copy: 
        src: files/httpd.conf 
        dest: /etc/httpd/conf/
      tags: 
        - conf
        - config
    
    - name: start httpd service
      service: 
        name: httpd 
        state=started 
        enabled=yes
      tags: 
        - service
        - start

- name: Install httpd
  yum: name=httpd state=present

• 特点：未指定任何标签
• 执行规则：
  • 使用--tags时会被跳过
  • 使用--skip-tags时会被执行
  • 不指定标签参数时会被执行

- name: Install configure file
  copy: 
    src: files/httpd.conf 
    dest: /etc/httpd/conf/
  tags: 
    - conf
    - config

• 特点：指定了两个标签（conf和config）
• 执行规则：
  • 当指定-t conf或-t config时会被执行
  • 当指定-t conf,config时也会被执行
  • 当指定-t service时会被跳过

- name: start httpd service
  service: 
    name: httpd 
    state=started 
    enabled=yes
  tags: 
    - service
    - start

• 特点：指定了两个标签（service和start）
• 执行规则：
  • 当指定-t service或-t start时会被执行
  • 当指定-t service,start时也会被执行
  • 当指定-t conf时会被跳过

ansible-playbook httpd.yml 
# 分析：所有任务都被执行

ansible-playbook -t conf httpd.yml 
# 分析：只有带有conf标签的任务被执行

ansible-playbook -t conf,service httpd.yml 
# 带有conf或service标签的任务都被执行

ansible-playbook --skip-tags service httpd.yml 
# 分析：跳过了带有service标签的任务

• 场景：复杂Playbook中任务可能属于多个类别

tasks:
  - name: Deploy web application
    copy: src=app.war dest=/var/lib/tomcat/webapps/
    tags:
      - deploy
      - web
      - app
  
  - name: Configure database
    template: src=db.j2 dest=/etc/app/db.conf
    tags:
      - config
      - db
      - app
  
  - name: Restart services
    service: name={{ item }} state=restarted
    loop:
      - tomcat
      - postgresql
    tags:
      - restart
      - service

• 执行示例：

# 执行所有与应用相关的任务
ansible-playbook -t app deploy.yml

# 执行部署和配置任务（跳过重启）
ansible-playbook -t deploy,config deploy.yml

# 执行除重启外的所有任务
ansible-playbook --skip-tags restart deploy.yml

• 场景：在角色中定义标签，在Playbook中继承

# roles/common/tasks/main.yml
- name: Update system packages
  yum: name=* state=latest
  tags: system

- name: Install common packages
  yum: name={{ item }} state=present
  loop:
    - vim
    - htop
    - git
  tags: packages

# playbook.yml
- hosts: webservers
  roles:
    - common
  tags:
    - always

• 场景：基于条件动态添加标签

- name: Install package based on OS
  yum: name={{ package_name }} state=present
  when: ansible_os_family == "RedHat"
  tags: install

- name: Configure service
  template: 
    src: service.conf.j2 
    dest: /etc/service/config
  when: service_config_changed is defined
  tags: config

• 执行示例：

# 仅在RedHat系统上执行安装任务 
ansible-playbook -t install playbook.yml

• 场景：使用标签控制服务重启

tasks:
  - name: Update configuration
    copy: 
      src: config.ini 
      dest: /etc/app/config.ini
    tags: config
    notify: restart app

handlers:
  - name: restart app
    service: name=app state=restarted
    tags: restart

• 执行示例：

# 仅执行配置更新并触发重启 
ansible-playbook -t config,restart deploy.yml

---
- hosts: webservers
  remote_user: root
  vars:
    app_name: "webapp"
    app_version: "1.2.3"
  tasks:
    # 基础环境任务
    - name: Update system packages
      yum: name=* state=latest
      tags: 
        - system
        - base
    
    - name: Install dependencies
      yum: 
        name: 
          - python3
          - git
          - nginx
        state: present
      tags: 
        - packages
        - base
    
    # 应用部署任务
    - name: Deploy application code
      git: 
        repo: https://github.com/example/webapp.git
        dest: /opt/{{ app_name }}
        version: "{{ app_version }}"
      tags: 
        - deploy
        - app
    
    - name: Deploy configuration files
      template: 
        src: "{{ item.src }}" 
        dest: "{{ item.dest }}"
      loop:
        - { src: app.conf.j2, dest: /etc/{{ app_name }}/app.conf }
        - { src: nginx.conf.j2, dest: /etc/nginx/conf.d/{{ app_name }}.conf }
      tags: 
        - config
        - app
    
    # 服务管理任务
    - name: Start and enable services
      service: 
        name: "{{ item }}" 
        state: started 
        enabled: yes
      loop:
        - nginx
        - {{ app_name }}
      tags: 
        - service
        - start
    
    - name: Check service status
      service: 
        name: "{{ item }}" 
        status: yes
      loop:
        - nginx
        - {{ app_name }}
      tags: 
        - check
        - status
  
  handlers:
    - name: Restart application
      service: name={{ app_name }} state=restarted
      tags: restart
    
    - name: Reload nginx
      service: name=nginx state=reloaded
      tags: reload

ansible-playbook -t base deploy.yml

ansible-playbook -t deploy deploy.yml

ansible-playbook -t base,app,service deploy.yml

ansible-playbook -t check deploy.yml

# 检查标签拼写
ansible-playbook -t conf,service deploy.yml  # 正确
ansible-playbook -t conf,servce deploy.yml   # 错误（拼写错误）

# 使用--list-tags查看可用标签
ansible-playbook --list-tags deploy.yml

# 检查任务标签定义
grep -n "tags:" deploy.yml

# 使用--tags时包含未标记任务
ansible-playbook --tags all deploy.yml

# 或使用--skip-tags排除特定标签
ansible-playbook --skip-tags test deploy.yml

# 使用更具体的标签名称
- name: Deploy frontend
  copy: src=frontend dest=/var/www/
  tags: deploy-frontend

- name: Deploy backend
  copy: src=backend dest=/var/www/
  tags: deploy-backend