引言

Ansible是简单强大的自动化运维工具。本文介绍Ansible的使用和实战。

一、Ansible安装

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# CentOS
yum install ansible

# Ubuntu
apt install ansible

# pip安装
pip install ansible

# 验证
ansible --version

二、Inventory配置

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# /etc/ansible/hosts
[web]
web1 ansible_host=192.168.1.10
web2 ansible_host=192.168.1.11

[db]
db1 ansible_host=192.168.1.20

[all:vars]
ansible_user=root
ansible_ssh_private_key_file=/root/.ssh/id_rsa

三、Ad-Hoc命令

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# ping测试
ansible all -m ping

# 执行命令
ansible web -m shell -a "uptime"

# 复制文件
ansible web -m copy -a "src=/tmp/file.txt dest=/tmp/"

# 安装软件
ansible web -m yum -a "name=nginx state=present"

# 启动服务
ansible web -m service -a "name=nginx state=started enabled=yes"

四、Playbook编写

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# nginx.yml
---
- name: Install and configure Nginx
  hosts: web
  become: yes
  
  vars:
    nginx_port: 80
    nginx_root: /var/www/html
  
  tasks:
    - name: Install Nginx
      yum:
        name: nginx
        state: present
    
    - name: Copy config file
      template:
        src: nginx.conf.j2
        dest: /etc/nginx/nginx.conf
      notify: Restart Nginx
    
    - name: Start Nginx
      service:
        name: nginx
        state: started
        enabled: yes
  
  handlers:
    - name: Restart Nginx
      service:
        name: nginx
        state: restarted
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# 执行Playbook
ansible-playbook nginx.yml

# 检查语法
ansible-playbook nginx.yml --syntax-check

# 模拟执行
ansible-playbook nginx.yml --check

五、角色（Roles）

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# 创建角色
ansible-galaxy init nginx

# 目录结构
nginx/
├── defaults/       # 默认变量
├── files/          # 文件
├── handlers/       # 处理器
├── meta/           # 元数据
├── tasks/          # 任务
├── templates/      # 模板
└── vars/           # 变量
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# tasks/main.yml
---
- name: Install Nginx
  yum:
    name: nginx
    state: present

- name: Configure Nginx
  template:
    src: nginx.conf.j2
    dest: /etc/nginx/nginx.conf
  notify: Restart Nginx

- name: Start Nginx
  service:
    name: nginx
    state: started
    enabled: yes
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# 使用角色
---
- hosts: web
  roles:
    - nginx
    - mysql

六、实战案例：部署Java应用

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---
- name: Deploy Java Application
  hosts: app
  become: yes
  
  vars:
    app_name: myapp
    app_port: 8080
    app_jar: myapp.jar
  
  tasks:
    - name: Install Java
      yum:
        name: java-11-openjdk
        state: present
    
    - name: Create app directory
      file:
        path: /opt/{{ app_name }}
        state: directory
    
    - name: Copy jar file
      copy:
        src: target/{{ app_jar }}
        dest: /opt/{{ app_name }}/{{ app_jar }}
    
    - name: Create systemd service
      template:
        src: app.service.j2
        dest: /etc/systemd/system/{{ app_name }}.service
    
    - name: Start application
      systemd:
        name: "{{ app_name }}"
        state: restarted
        enabled: yes
        daemon_reload: yes

总结

Ansible核心：

  1. 无Agent：SSH连接，无需安装客户端
  2. Playbook：YAML格式，易读易写
  3. 幂等性：多次执行结果一致
  4. 角色：模块化组织

参考资料