# Ansible 实战指南

## 目录

1. [运维自动化发展历程及技术应用](#1-运维自动化发展历程及技术应用)
2. [Ansible 架构和相关命令使用](#2-ansible-架构和相关命令使用)
3. [Ansible 常用模块详解](#3-ansible-常用模块详解)
4. [Ansible Playbook 基础](#4-ansible-playbook-基础)
5. [Playbook 变量、Tags、Handlers 使用](#5-playbook-变量tagshandlers使用)
6. [Playbook 模板 Templates](#6-playbook-模板-templates)
7. [Playbook 条件判断 When](#7-playbook-条件判断-when)
8. [Playbook 字典 with_items](#8-playbook-字典-with_items)
9. [Ansible Roles](#9-ansible-roles)

---

## 1. 运维自动化发展历程及技术应用

### 1.1 运维自动化发展历程

```
┌─────────────────────────────────────────────────────┐
│               运维自动化发展历程                       │
├─────────────────────────────────────────────────────┤
│                                                     │
│  1. 手动时代                                          │
│     ├── 人工登录服务器                                │
│     ├── 逐台执行命令                                  │
│     └── 效率低下，易出错                             │
│                                                     │
│  2. 脚本时代                                         │
│     ├── Shell/Python 脚本                           │
│     ├── 批量执行脚本                                 │
│     └── 脚本难以维护，无标准化                        │
│                                                     │
│  3. 工具时代                                         │
│     ├── Puppet、SaltStack、Chef                     │
│     ├── 配置管理工具                                 │
│     └── 解决一致性，但复杂                           │
│                                                     │
│  4. 自动化时代                                       │
│     ├── Ansible、Terraform                          │
│     ├── 简单易用，Agentless                         │
│     └── 编排 + 自动化                                │
│                                                     │
│  5. DevOps 时代                                      │
│     ├── CI/CD + 自动化运维                          │
│     ├── Kubernetes + 容器                           │
│     └── GitOps 理念                                  │
│                                                     │
└─────────────────────────────────────────────────────┘
```

### 1.2 常见运维自动化工具对比

| 工具 | 类型 | 架构 | 优点 | 缺点 |
|------|------|------|------|------|
| **Ansible** | 配置管理/编排 | Agentless | 简单易学、YAML 语法、无 Agent | 执行速度稍慢 |
| **Puppet** | 配置管理 | C/S (Agent) | 功能强大、成熟 | 学习曲线陡峭 |
| **SaltStack** | 配置管理/执行 | C/S (Agent) | 高性能、可远程执行 | 语法复杂 |
| **Chef** | 配置管理 | C/S (Agent) | Ruby 语法、社区活跃 | 需要编写 Ruby 代码 |
| **Terraform** | 基础设施代码 | Agentless | 基础设施即代码、云原生 | 专注于基础设施 |

### 1.3 Ansible 应用场景

| 场景 | 说明 |
|------|------|
| **配置管理** | 统一配置服务器、操作系统、应用软件 |
| **应用部署** | 自动化部署应用程序、容器 |
| **批量操作** | 批量执行命令、批量修改配置 |
| ** orchestration** | 多节点编排、任务编排 |
| **持续交付** | CI/CD 流水线集成 |
| **基础设施** | 云资源管理、容器编排 |

### 1.4 Ansible 在企业中的应用

```
┌─────────────────────────────────────────────────────┐
│               Ansible 企业应用架构                   │
├─────────────────────────────────────────────────────┤
│                                                     │
│  ┌─────────────────────────────────────────────┐   │
│  │              Ansible Control Node            │   │
│  │              (Ansible Server)               │   │
│  └────────────────────┬────────────────────────┘   │
│                       │                              │
│         ┌─────────────┼─────────────┐              │
│         │             │             │              │
│         ▼             ▼             ▼              │
│   ┌──────────┐  ┌──────────┐  ┌──────────┐        │
│   │ Web      │  │ App      │  │ Database │        │
│   │ Servers  │  │ Servers  │  │ Servers  │        │
│   └──────────┘  └──────────┘  └──────────┘        │
│                                                     │
│  场景：                                            │
│  - 批量部署/配置服务器                              │
│  - 应用发布和回滚                                   │
│  - 监控和日志收集                                   │
│  - 安全合规检查                                     │
│                                                     │
└─────────────────────────────────────────────────────┘
```

---

## 2. Ansible 架构和相关命令使用

### 2.1 Ansible 架构

```
┌─────────────────────────────────────────────────────┐
│                 Ansible 架构                         │
├─────────────────────────────────────────────────────┤
│                                                     │
│  ┌─────────────────────────────────────────────┐   │
│  │              Ansible Engine                 │   │
│  │                                             │   │
│  │  Inventory    ──→  Playbooks               │   │
│  │     │              │                       │   │
│  │     ▼              ▼                       │   │
│  │  Plugins    ──→  Modules                  │   │
│  │     │              │                       │   │
│  │     │              │                       │   │
│  │     └──────────────┘                       │   │
│  │           │                                │   │
│  └───────────┼────────────────────────────────┘   │
│              │                                     │
│              ▼                                     │
│  ┌─────────────────────────────────────────────┐   │
│  │            Managed Nodes                     │   │
│  │            (无 Agent)                        │   │
│  │                                             │   │
│  │  SSH Connection ──→ Execute Modules         │   │
│  │                                             │   │
│  └─────────────────────────────────────────────┘   │
│                                                     │
└─────────────────────────────────────────────────────┘
```

### 2.2 Ansible 核心组件

| 组件 | 说明 |
|------|------|
| **Inventory** | 主机清单，定义管理的主机 |
| **Playbook** | 任务剧本，YAML 格式的任务定义 |
| **Module** | 模块，Ansible 执行的具体任务单元 |
| **Plugin** | 插件，扩展 Ansible 功能 |
| **API** | 编程接口，供二次开发使用 |

### 2.3 Ansible 安装

```bash
# 使用 pip 安装
pip install ansible

# Ubuntu/Debian
apt install ansible

# CentOS/RHEL
yum install epel-release
yum install ansible

# macOS
brew install ansible

# 验证安装
ansible --version
```

### 2.4 Inventory 主机清单

#### 2.4.1 静态 Inventory

```ini
# /etc/ansible/hosts 或 -i 指定文件

# 单主机
192.168.1.10

# 主机组
[web]
192.168.1.10
192.168.1.11
192.168.1.12

[db]
192.168.1.20
192.168.1.21

# 嵌套组
[production:children]
web
db

# 主机变量
[web]
192.168.1.10 ansible_user=admin ansible_ssh_pass=pass123
192.168.1.11 ansible_user=admin ansible_ssh_pass=pass123

# 组变量
[web:vars]
ansible_user=admin
ansible_ssh_pass=pass123
http_port=80
```

#### 2.4.2 动态 Inventory

```bash
# 使用脚本获取主机列表
ansible-playbook -i inventory.py playbook.yml

# AWS EC2 动态 Inventory
ansible-playbook -i ec2.py playbook.yml
```

### 2.5 Ansible 配置文件

```ini
# ansible.cfg

[defaults]
inventory = /etc/ansible/hosts
host_key_checking = False
retry_files_enabled = False
gathering = explicit
# 加速配置
pipelining = True
# 并行数
forks = 50

[privilege_escalation]
become = True
become_method = sudo
become_user = root
become_ask_pass = False

[ssh_connection]
ssh_args = -o ControlMaster=auto -o ControlPersist=60s
pipelining = True
```

### 2.6 常用命令

```bash
# 帮助
ansible-doc -h
ansible-doc <module_name>
ansible-doc -l  # 列出所有模块

# 测试连通性
ansible all -m ping

# 执行临时命令
ansible all -m command -a "uptime"
ansible all -m shell -a "df -h"
ansible all -m setup  # 获取主机信息

# 文件传输
ansible all -m copy -a "src=/tmp/file dest=/tmp/"

# 用户管理
ansible all -m user -a "name=test state=present"

# 包管理
ansible all -m yum -a "name=httpd state=present"

# 服务管理
ansible all -m service -a "name=httpd state=started"

# 查看配置
ansible-config dump

# 查看清单
ansible-inventory --list
```

### 2.7 Playbook 命令

```bash
# 执行 playbook
ansible-playbook playbook.yml

# 检查模式（不执行）
ansible-playbook --check playbook.yml

# 差异化执行（检查变更）
ansible-playbook --diff playbook.yml

# 指定主机
ansible-playbook -i inventory.ini playbook.yml

# 指定标签
ansible-playbook --tags "web" playbook.yml

# 跳过标签
ansible-playbook --skip-tags "debug" playbook.yml

# 启动步骤
ansible-playbook --start-at-task "Install Apache" playbook.yml

# 步骤执行
ansible-playbook --step playbook.yml

# 详细输出
ansible-playbook -v playbook.yml
ansible-playbook -vv playbook.yml
ansible-playbook -vvv playbook.yml  # 详细调试

# 清缓存
ansible-playbook --flush-cache playbook.yml
```

---

## 3. Ansible 常用模块详解

### 3.1 模块分类

| 分类 | 说明 | 常见模块 |
|------|------|----------|
| **命令执行** | 执行远程命令 | command, shell, script, raw |
| **文件操作** | 文件管理 | copy, file, template, synchronize |
| **包管理** | 软件包管理 | yum, apt, package |
| **服务管理** | 服务管理 | service, systemd |
| **用户管理** | 用户管理 | user, group |
| **数据库** | 数据库操作 | mysql_db, postgresql_db |
| **云资源** | 云资源管理 | ec2, azure_rm, gce |
| **容器** | 容器管理 | docker, k8s |
| **通知** | 通知模块 | email, slack |

### 3.2 命令执行模块

#### 3.2.1 command 模块

```yaml
- name: Execute command
  command: uptime

- name: Execute with args
  command: systemctl start nginx

- name: Check file exists
  command: test -f /etc/nginx/nginx.conf
  register: result

- name: Create directory
  command: mkdir -p /tmp/test
  creates: /tmp/test  # 存在则跳过
```

#### 3.2.2 shell 模块

```yaml
- name: Execute shell
  shell: echo $PATH

- name: Execute with pipe
  shell: cat /etc/passwd | grep root

- name: Execute script
  shell: |
    #!/bin/bash
    echo "Hello"
```

#### 3.2.3 script 模块

```yaml
- name: Run local script
  script: /tmp/script.sh

- name: Run with args
  script: /tmp/script.sh --arg1 value1

- name: Run on remote
  script: /tmp/script.sh
  args:
    creates: /tmp/result
```

### 3.3 文件操作模块

#### 3.3.1 copy 模块

```yaml
- name: Copy file
  copy:
    src: /tmp/source.conf
    dest: /etc/nginx/nginx.conf
    owner: root
    group: root
    mode: '0644'

- name: Copy with backup
  copy:
    src: /tmp/source.conf
    dest: /etc/nginx/nginx.conf
    backup: yes

- name: Copy content
  copy:
    dest: /tmp/test.txt
    content: "Hello World"
```

#### 3.3.2 file 模块

```yaml
- name: Create directory
  file:
    path: /tmp/dir
    state: directory
    mode: '0755'

- name: Create file
  file:
    path: /tmp/file
    state: touch

- name: Create symlink
  file:
    src: /tmp/source
    dest: /tmp/link
    state: link

- name: Delete file
  file:
    path: /tmp/file
    state: absent
```

#### 3.3.3 template 模块

```yaml
- name: Template file
  template:
    src: nginx.conf.j2
    dest: /etc/nginx/nginx.conf
    owner: root
    group: root
    mode: '0644'
    validate: 'nginx -t -c %s'
```

#### 3.3.4 synchronize 模块

```yaml
- name: Sync directory
  synchronize:
    src: /tmp/local/
    dest: /tmp/remote/
    delete: yes
    rsync_opts:
      - "--exclude=.git"
```

### 3.4 包管理模块

#### 3.4.1 yum 模块

```yaml
- name: Install package
  yum:
    name: nginx
    state: present

- name: Install latest
  yum:
    name: '*'
    state: latest

- name: Install multiple
  yum:
    name:
      - nginx
      - php-fpm
    state: present

- name: Remove package
  yum:
    name: nginx
    state: absent

- name: Install from repo
  yum:
    name: epel-release
    enablerepo: epel
```

#### 3.4.2 apt 模块

```yaml
- name: Install package
  apt:
    name: nginx
    state: present
    update_cache: yes

- name: Install without update
  apt:
    name: nginx
    state: present
    update_cache: no

- name: Install from deb
  apt:
    deb: /tmp/package.deb
    state: present
```

### 3.5 服务管理模块

#### 3.5.1 service 模块

```yaml
- name: Start service
  service:
    name: nginx
    state: started
    enabled: yes

- name: Stop service
  service:
    name: nginx
    state: stopped

- name: Restart service
  service:
    name: nginx
    state: restarted

- name: Reload service
  service:
    name: nginx
    state: reloaded
```

#### 3.5.2 systemd 模块

```yaml
- name: Enable and start service
  systemd:
    name: nginx
    state: started
    enabled: yes
    daemon_reload: yes
```

### 3.6 用户管理模块

#### 3.6.1 user 模块

```yaml
- name: Create user
  user:
    name: appuser
    comment: "Application User"
    shell: /bin/bash
    home: /home/appuser
    create_home: yes

- name: Create with password
  user:
    name: admin
    password: "{{ 'password' | password_hash('sha512') }}"

- name: Add to group
  user:
    name: appuser
    groups:
      - wheel
      - docker
    append: yes

- name: Remove user
  user:
    name: appuser
    state: absent
    remove: yes
```

#### 3.6.2 group 模块

```yaml
- name: Create group
  group:
    name: mygroup
    state: present
    gid: 1000
```

### 3.7 其他常用模块

#### 3.7.1 get_url 模块

```yaml
- name: Download file
  get_url:
    url: http://example.com/file.tar.gz
    dest: /tmp/file.tar.gz
    mode: '0644'
```

#### 3.7.2 unarchive 模块

```yaml
- name: Unarchive file
  unarchive:
    src: /tmp/file.tar.gz
    dest: /tmp/
    remote_src: no
```

#### 3.7.3 lineinfile 模块

```yaml
- name: Add line
  lineinfile:
    path: /etc/selinux/config
    regexp: '^SELINUX='
    line: SELINUX=enforcing

- name: Remove line
  lineinfile:
    path: /etc/selinux/config
    regexp: '^SELINUX='
    state: absent
```

#### 3.7.4 find 模块

```yaml
- name: Find files
  find:
    paths: /var/log
    patterns: "*.log"
    age: 7d
  register: log_files
```

---

## 4. Ansible Playbook 基础

### 4.1 Playbook 概述

Playbook 是 Ansible 的任务配置文件，使用 YAML 格式编写，定义了一组有序的任务。

```
┌─────────────────────────────────────────────────────┐
│                Playbook 结构                         │
├─────────────────────────────────────────────────────┤
│                                                     │
│  Playbook (剧本)                                    │
│  ├── Play 1                                         │
│  │   ├── Hosts (主机)                               │
│  │   ├── Vars (变量)                                │
│  │   └── Tasks (任务)                              │
│  │       ├── Task 1 (Module)                       │
│  │       └── Task 2 (Module)                       │
│  │                                              │
│  └── Play 2                                         │
│      ├── Hosts                                      │
│      ├── Vars                                       │
│      └── Tasks                                     │
│                                                     │
└─────────────────────────────────────────────────────┘
```

### 4.2 基础 Playbook 示例

```yaml
# playbook.yml
---
- name: Configure Web Server
  hosts: web
  become: yes
  
  vars:
    http_port: 80
    
  tasks:
    - name: Install Apache
      yum:
        name: httpd
        state: present
        
    - name: Ensure Apache is running
      service:
        name: httpd
        state: started
        enabled: yes
        
    - name: Copy configuration
      copy:
        src: files/httpd.conf
        dest: /etc/httpd/conf/httpd.conf
      notify: Restart Apache
      
    - name: Copy index page
      template:
        src: templates/index.html.j2
        dest: /var/www/html/index.html
        
  handlers:
    - name: Restart Apache
      service:
        name: httpd
        state: restarted
```

### 4.3 多个 Play

```yaml
---
- name: Configure Web Servers
  hosts: web
  become: yes
  
  tasks:
    - name: Install Apache
      yum:
        name: httpd
        state: present
        
    - name: Start Apache
      service:
        name: httpd
        state: started

- name: Configure Database Servers
  hosts: db
  become: yes
  
  tasks:
    - name: Install MySQL
      yum:
        name: mysql-server
        state: present
        
    - name: Start MySQL
      service:
        name: mysqld
        state: started
```

### 4.4 Play 常用参数

| 参数 | 说明 |
|------|------|
| `name` | Play 名称 |
| `hosts` | 目标主机 |
| `become` | 是否提权 |
| `become_method` | 提权方式（sudo/su） |
| `become_user` | 提权用户 |
| `gather_facts` | 是否收集主机信息 |
| `vars` | 变量 |
| `tasks` | 任务列表 |
| `handlers` | 处理器 |
| `roles` | 角色 |

### 4.5 Task 常用参数

| 参数 | 说明 |
|------|------|
| `name` | 任务名称 |
| `module` | 使用的模块 |
| `args` | 模块参数 |
| `when` | 条件判断 |
| `register` | 注册变量 |
| `changed_when` | 改变判断条件 |
| `failed_when` | 失败判断条件 |
| `loop` | 循环 |
| `until` | 循环直到 |
| `retries` | 重试次数 |
| `delay` | 重试延迟 |

### 4.6 任务控制

```yaml
# 顺序执行
- name: Task 1
  yum:
    name: httpd
    state: present
    
- name: Task 2
  service:
    name: httpd
    state: started

# 忽略错误
- name: Ignore error
  command: /some/command
  ignore_errors: yes

# 强制失败
- name: Force fail
  command: /some/command
  failed_when: "'FAILED' in result.stderr"

# 标签
- name: Install packages
  yum:
    name: "{{ item }}"
  tags:
    - packages
    - web
```

---

## 5. Playbook 变量、Tags、Handlers 使用

### 5.1 变量

#### 5.1.1 变量定义

```yaml
# 方式 1：Play 变量
- hosts: web
  vars:
    http_port: 80
    server_name: example.com
    
  tasks:
    - name: Use variable
      debug:
        msg: "Port is {{ http_port }}"

# 方式 2：Task 变量
- name: Task variable
  debug:
    msg: "{{ task_var }}"
  vars:
    task_var: "Hello"
```

#### 5.1.2 主机变量

```ini
# inventory
[web]
192.168.1.10 http_port=8080
192.168.1.11 http_port=8090
```

#### 5.1.3 组变量

```yaml
# group_vars/all.yml
---
ansible_user: admin
ansible_ssh_pass: password

# group_vars/web.yml
---
http_port: 80
```

#### 5.1.4 变量引用

```yaml
- name: Reference variables
  debug:
    msg: "{{ variable_name }}"
    
- name: Complex reference
  debug:
    msg: "{{ hostvars[groups['web'][0]]['ansible_host'] }}"
```

#### 5.1.5 Facts 变量

```yaml
# 获取 facts
- name: Get facts
  setup:
    filter: ansible_*

- name: Show facts
  debug:
    msg: "{{ ansible_hostname }}"
    
# 常用 facts
# ansible_hostname - 主机名
# ansible_default_ipv4.address - IP 地址
# ansible_distribution - 发行版
# ansible_distribution_version - 版本
# ansible_memory_mb.real.total - 内存
# ansible_processor_vcpus - CPU 核心数
```

### 5.2 Tags

#### 5.2.1 Tag 定义

```yaml
- name: Install Apache
  yum:
    name: httpd
    state: present
  tags:
    - web
    - httpd
    
- name: Configure Apache
  template:
    src: httpd.conf.j2
    dest: /etc/httpd/conf/httpd.conf
  tags:
    - config
    - httpd
```

#### 5.2.2 Tag 使用

```bash
# 只执行带 tag 的任务
ansible-playbook --tags "web" playbook.yml

# 跳过 tag
ansible-playbook --skip-tags "debug" playbook.yml

# 多个 tag
ansible-playbook --tags "web,mysql" playbook.yml
```

### 5.3 Handlers

#### 5.3.1 Handler 定义

```yaml
- name: Configure Apache
  template:
    src: httpd.conf.j2
    dest: /etc/httpd/conf/httpd.conf
  notify:
    - Restart Apache
    
handlers:
  - name: Restart Apache
    service:
      name: httpd
      state: restarted
```

#### 5.3.2 多个 Handlers

```yaml
- name: Configure Apache
  template:
    src: httpd.conf.j2
    dest: /etc/httpd/conf/httpd.conf
  notify:
    - Restart Apache
    - Reload Nginx
    
handlers:
  - name: Restart Apache
    service:
      name: httpd
      state: restarted
      
  - name: Reload Nginx
    service:
      name: nginx
      state: reloaded
```

#### 5.3.3 Handler 监听

```yaml
- name: Config changed
  template:
    src: app.conf.j2
    dest: /etc/app.conf
  notify:
    - Notify handler
    
handlers:
  - name: Notify handler
    service:
      name: app
      state: restarted
    listen: "config changed"
```

---

## 6. Playbook 模板 Templates

### 6.1 Jinja2 模板概述

Ansible 使用 Jinja2 作为模板引擎，支持变量、过滤器、循环等特性。

### 6.2 基础模板

```jinja
{# config.conf.j2 #}
# Server configuration
ServerName {{ server_name }}
Listen {{ http_port }}
DocumentRoot "{{ document_root }}"

{% if enable_ssl %}
SSLEngine on
SSLCertificateFile {{ ssl_cert }}
SSLCertificateKeyFile {{ ssl_key }}
{% endif %}
```

### 6.3 变量和过滤器

```jinja
{# 使用变量 #}
{{ variable }}

{# 默认值 #}
{{ variable | default('default_value') }}

{# 过滤器 #}
{{ name | upper }}
{{ list | join(',') }}
{{ number | int }}

{# 条件判断 #}
{% if var == 'value' %}
...
{% endif %}

{# 循环 #}
{% for item in items %}
{{ item }}
{% endfor %}
```

### 6.4 完整示例

```yaml
# playbook.yml
---
- name: Configure Nginx
  hosts: web
  become: yes
  
  vars:
    server_name: example.com
    http_port: 80
    document_root: /var/www/html
    enable_ssl: true
    ssl_cert: /etc/nginx/ssl/server.crt
    ssl_key: /etc/nginx/ssl/server.key
    
  tasks:
    - name: Ensure Nginx installed
      yum:
        name: nginx
        state: present
        
    - name: Configure Nginx
      template:
        src: nginx.conf.j2
        dest: /etc/nginx/nginx.conf
        validate: 'nginx -t -c %s'
      notify: Restart Nginx
      
  handlers:
    - name: Restart Nginx
      service:
        name: nginx
        state: restarted
```

```jinja
{# nginx.conf.j2 #}
user nginx;
worker_processes {{ worker_processes | default('auto') }};
error_log /var/log/nginx/error.log;

events {
    worker_connections {{ worker_connections | default(1024) }};
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';
    
    access_log /var/log/nginx/access.log main;
    
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout {{ keepalive_timeout | default(65) }};
    
    upstream backend {
        {% for server in upstream_servers %}
        server {{ server.host }}:{{ server.port }}{% if server.weight %} weight={{ server.weight }}{% endif %};
        {% endfor %}
    }
    
    server {
        listen {{ http_port }};
        server_name {{ server_name }};
        
        root {{ document_root }};
        
        {% if enable_ssl %}
        listen 443 ssl http2;
        ssl_certificate {{ ssl_cert }};
        ssl_certificate_key {{ ssl_key }};
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;
        {% endif %}
        
        location / {
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
        }
    }
}
```

### 6.5 模板变量文件

```yaml
# group_vars/web.yml
---
server_name: example.com
http_port: 80
document_root: /var/www/html
enable_ssl: true
ssl_cert: /etc/nginx/ssl/server.crt
ssl_key: /etc/nginx/ssl/server.key

upstream_servers:
  - host: 192.168.1.10
    port: 8080
    weight: 5
  - host: 192.168.1.11
    port: 8080
    weight: 3

worker_processes: 4
worker_connections: 2048
keepalive_timeout: 60
```

---

## 7. Playbook 条件判断 When

### 7.1 when 基础

```yaml
- name: Install Apache on CentOS
  yum:
    name: httpd
    state: present
  when: ansible_os_family == "RedHat"

- name: Install Apache on Debian
  apt:
    name: apache2
    state: present
  when: ansible_os_family == "Debian"
```

### 7.2 多个条件

```yaml
# AND 条件
- name: Install on specific OS
  yum:
    name: httpd
    state: present
  when:
    - ansible_os_family == "RedHat"
    - ansible_distribution_version | int >= 7

# OR 条件
- name: Install web server
  yum:
    name: nginx
    state: present
  when: ansible_os_family == "RedHat" or ansible_os_family == "Debian"
```

### 7.3 变量判断

```yaml
- name: Register variable
  command: /usr/bin/test -f /etc/httpd/conf/httpd.conf
  register: httpd_conf
  
- name: Check result
  debug:
    msg: "Config file exists"
  when: httpd_conf.rc == 0

- name: Check changed
  command: /usr/bin/some-command
  register: result
  changed_when: result.rc != 0

- name: Conditional execution
  debug:
    msg: "Command changed"
  when: result is changed
```

### 7.4 内置条件测试

```yaml
- name: Test defined
  debug:
    msg: "Variable defined"
  when: my_var is defined

- name: Test undefined
  debug:
    msg: "Variable not defined"
  when: my_var is not defined

- name: Test true
  debug:
    msg: "Value is true"
  when: my_var | bool

- name: Test false
  debug:
    msg: "Value is false"
  when: not my_var | bool

- name: Test string
  debug:
    msg: "String test"
  when: my_string == "value"

- name: Test number
  debug:
    msg: "Number test"
  when: my_number > 100

- name: Test in
  debug:
    msg: "In list"
  when: ansible_hostname in groups['web']
```

### 7.5 循环 + 条件

```yaml
- name: Install packages based on OS
  yum:
    name: "{{ item }}"
    state: present
  loop:
    - httpd
    - nginx
  when: ansible_os_family == "RedHat"

- name: Install specific packages
  apt:
    name: "{{ item.name }}"
    state: present
  loop:
    - { name: 'apache2', os: 'Debian' }
    - { name: 'httpd', os: 'RedHat' }
  when: ansible_os_family == item.os
```

### 7.6 完整示例

```yaml
---
- name: Configure servers based on OS
  hosts: all
  gather_facts: yes
  
  vars:
    install_web: true
    install_db: false
    
  tasks:
    - name: Install Apache
      yum:
        name: httpd
        state: present
      when:
        - install_web | bool
        - ansible_os_family == "RedHat"
        
    - name: Install Apache on Debian
      apt:
        name: apache2
        state: present
      when:
        - install_web | bool
        - ansible_os_family == "Debian"
        
    - name: Install MySQL
      yum:
        name: mysql-server
        state: present
      when:
        - install_db | bool
        - ansible_distribution == "CentOS"
        
    - name: Configure firewall for CentOS 7+
      firewalld:
        service: http
        permanent: yes
        state: enabled
      when:
        - ansible_os_family == "RedHat"
        - ansible_distribution_version | int >= 7
        
    - name: Only on web servers
      debug:
        msg: "This is a web server"
      when: "'web' in group_names"
```

---

## 8. Playbook 字典 with_items

### 8.1 with_items 基础

```yaml
- name: Install multiple packages
  yum:
    name: "{{ item }}"
    state: present
  loop:
    - httpd
    - nginx
    - php-fpm
    
- name: Create users
  user:
    name: "{{ item }}"
    state: present
  loop:
    - alice
    - bob
    - charlie
```

### 8.2 字典列表

```yaml
- name: Create multiple users with attributes
  user:
    name: "{{ item.name }}"
    comment: "{{ item.comment }}"
    shell: "{{ item.shell }}"
    create_home: yes
  loop:
    - { name: 'alice', comment: 'Alice User', shell: '/bin/bash' }
    - { name: 'bob', comment: 'Bob User', shell: '/bin/sh' }
```

### 8.3 嵌套循环

```yaml
- name: Create directories
  file:
    path: "{{ item.0 }}/{{ item.1 }}"
    state: directory
  loop:
    - ['/tmp', 'dir1']
    - ['/tmp', 'dir2']
    - ['/var', 'log']
```

### 8.4 with_dict

```yaml
- name: Define dictionary
  set_fact:
    users:
      alice:
        shell: /bin/bash
        home: /home/alice
      bob:
        shell: /bin/sh
        home: /home/bob
        
- name: Create users from dict
  user:
    name: "{{ item.key }}"
    shell: "{{ item.value.shell }}"
    home: "{{ item.value.home }}"
  loop: "{{ dict(users) | dict2items }}"
```

### 8.5 with_fileglob

```yaml
- name: Copy all files
  copy:
    src: "{{ item }}"
    dest: /tmp/
    mode: '0644'
  loop:
    - "{{ playbook_dir }}/files/*"
```

### 8.6 with_sequence

```yaml
- name: Create sequence files
  file:
    path: "/tmp/file{{ item }}"
    state: touch
  loop: "{{ range(1, 11) | list }}"
```

### 8.7 with_together

```yaml
- name: Combine lists
  debug:
    msg: "{{ item.0 }} - {{ item.1 }}"
  loop: "{{ list1 | zip(list2) | list }}"
```

### 8.8 with_nested

```yaml
- name: Nested loop
  debug:
    msg: "{{ item.0 }} - {{ item.1 }}"
  loop: "{{ ['a', 'b', 'c'] | product(['1', '2', '3']) | list }}"
```

### 8.9 注册变量 + 循环

```yaml
- name: Get file contents
  command: cat {{ item }}
  register: file_contents
  loop:
    - /tmp/file1.txt
    - /tmp/file2.txt
    
- name: Show contents
  debug:
    msg: "{{ item.stdout }}"
  loop: "{{ file_contents.results }}"
```

### 8.10 完整示例

```yaml
---
- name: Configure multi-tier application
  hosts: app
  
  vars:
    app_users:
      - { name: 'appuser', uid: 1000, group: 'app', shell: '/bin/bash' }
      - { name: 'deploy', uid: 1001, group: 'app', shell: '/bin/sh' }
      
    app_dirs:
      - { path: '/opt/app', owner: 'appuser', mode: '0755' }
      - { path: '/var/log/app', owner: 'appuser', mode: '0755' }
      - { path: '/tmp/app', owner: 'appuser', mode: '1777' }
      
    packages:
      - java-11-openjdk
      - maven
      - git
      
  tasks:
    - name: Create groups
      group:
        name: "{{ item }}"
        state: present
      loop:
        - app
        - deploy
        
    - name: Create users
      user:
        name: "{{ item.name }}"
        uid: "{{ item.uid }}"
        group: "{{ item.group }}"
        shell: "{{ item.shell }}"
        create_home: yes
      loop: "{{ app_users }}"
      
    - name: Create directories
      file:
        path: "{{ item.path }}"
        owner: "{{ item.owner }}"
        mode: "{{ item.mode }}"
        state: directory
      loop: "{{ app_dirs }}"
      
    - name: Install packages
      yum:
        name: "{{ item }}"
        state: present
      loop: "{{ packages }}"
      when: ansible_os_family == "RedHat"
      
    - name: Install packages (Debian)
      apt:
        name: "{{ item }}"
        state: present
        update_cache: yes
      loop: "{{ packages }}"
      when: ansible_os_family == "Debian"
```

---

## 9. Ansible Roles

### 9.1 Roles 概述

Roles 是 Ansible 的组织结构化机制，将 Playbook 分解为可重用的组件。

```
┌─────────────────────────────────────────────────────┐
│                 Roles 目录结构                        │
├─────────────────────────────────────────────────────┤
│                                                     │
│  roles/                                            │
│  └── role_name/                                    │
│      ├── defaults/          # 默认变量（最低优先级）│
│      │   └── main.yml                             │
│      ├── vars/             # 变量（最高优先级）   │
│      │   └── main.yml                             │
│      ├── tasks/            # 任务                 │
│      │   └── main.yml                             │
│      ├── handlers/         # 处理器               │
│      │   └── main.yml                             │
│      ├── templates/        # 模板                 │
│      │   └── *.j2                                 │
│      ├── files/           # 静态文件             │
│      │   └── *                                    │
│      ├── meta/            # 依赖关系             │
│      │   └── main.yml                             │
│      └── README.md        # 文档                 │
│                                                     │
└─────────────────────────────────────────────────────┘
```

### 9.2 创建 Role

```bash
# 使用 ansible-galaxy 创建
ansible-galaxy init role_name

# 手动创建目录结构
mkdir -p roles/nginx/{defaults,vars,tasks,handlers,templates,files,meta}
```

### 9.3 Role 示例：Nginx

#### 9.3.1 defaults/main.yml

```yaml
---
# defaults/main.yml
nginx_version: "1.24"
nginx_port: 80
nginx_worker_processes: auto
nginx_worker_connections: 1024
nginx_server_name: localhost
nginx_document_root: /var/www/html
```

#### 9.3.2 vars/main.yml

```yaml
---
# vars/main.yml
nginx_user: nginx
nginx_group: nginx
nginx_conf_dir: /etc/nginx
nginx_log_dir: /var/log/nginx
```

#### 9.3.3 tasks/main.yml

```yaml
---
# tasks/main.yml
- name: Ensure nginx is installed
  yum:
    name: nginx
    state: present
  when: ansible_os_family == "RedHat"

- name: Ensure nginx is installed
  apt:
    name: nginx
    state: present
    update_cache: yes
  when: ansible_os_family == "Debian"

- name: Copy nginx configuration
  template:
    src: nginx.conf.j2
    dest: /etc/nginx/nginx.conf
  notify: Restart nginx

- name: Ensure nginx is running
  service:
    name: nginx
    state: started
    enabled: yes
```

#### 9.3.4 handlers/main.yml

```yaml
---
# handlers/main.yml
- name: Restart nginx
  service:
    name: nginx
    state: restarted
    
- name: Reload nginx
  service:
    name: nginx
    state: reloaded
```

#### 9.3.5 templates/nginx.conf.j2

```jinja
# nginx.conf.j2
user {{ nginx_user }};
worker_processes {{ nginx_worker_processes }};
error_log {{ nginx_log_dir }}/error.log;

events {
    worker_connections {{ nginx_worker_connections }};
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';
    
    access_log {{ nginx_log_dir }}/access.log main;
    
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    
    server {
        listen {{ nginx_port }};
        server_name {{ nginx_server_name }};
        
        root {{ nginx_document_root }};
        
        location / {
            index index.html index.htm;
        }
    }
}
```

### 9.4 使用 Role

```yaml
# site.yml
---
- name: Configure web servers
  hosts: web
  
  roles:
    - role: nginx
      nginx_port: 8080
      nginx_server_name: example.com
      
- name: Configure database servers
  hosts: db
  
  roles:
    - role: mysql
      mysql_port: 3306
```

### 9.5 Role 依赖

```yaml
# roles/common/meta/main.yml
---
dependencies:
  - role: common
    vars:
      common_version: 1.0
  - role: monitoring
```

### 9.6 完整 Playbook 示例

```yaml
# site.yml - 完整项目配置
---
- name: Infrastructure setup
  hosts: all
  gather_facts: yes
  
  roles:
    - common
    - ntp

- name: Web servers setup
  hosts: web
  become: yes
  
  roles:
    - nginx
    - php-fpm
    - firewall
    
- name: Database servers setup
  hosts: db
  become: yes
  
  roles:
    - mysql
    - backup
    
- name: Application deployment
  hosts: app
  become: yes
  
  roles:
    - app_deploy
    - monitoring_agent
```

### 9.7 导入 Role

```yaml
# 静态导入
- name: Import role
  import_role:
    name: nginx
  vars:
    nginx_port: 8080

- name: Import handlers
  import_tasks: handlers.yml
```

### 9.8 动态 Role

```yaml
# 动态导入
- name: Include role
  include_role:
    name: nginx
  vars:
    nginx_port: 80
```

### 9.9 Galaxy 角色

```bash
# 搜索角色
ansible-galaxy search nginx

# 安装角色
ansible-galaxy install geerlingguy.nginx

# 查看已安装角色
ansible-galaxy list

# 删除角色
ansible-galaxy remove geerlingguy.nginx
```

---

## 附录

### 常用命令速查

| 命令 | 说明 |
|------|------|
| `ansible all -m ping` | 测试连通性 |
| `ansible-playbook site.yml` | 执行 Playbook |
| `ansible-playbook --check site.yml` | 模拟执行 |
| `ansible-playbook --tags "web" site.yml` | 指定标签 |
| `ansible-doc -l` | 列出模块 |
| `ansible-doc user` | 查看模块文档 |
| `ansible-galaxy init role` | 创建角色 |
| `ansible-config dump` | 查看配置 |

### 配置参数速查

| 参数 | 说明 |
|------|------|
| `inventory` | 主机清单 |
| `forks` | 并行数 |
| `become` | 提权 |
| `host_key_checking` | 主机指纹检查 |
| `retry_files_enabled` | 重试文件 |

### 变量优先级

| 优先级（低到高） |
|----------|
| role defaults |
| inventory file/script group vars |
| inventory group vars |
| playbook group vars |
| host facts |
| register vars |
| set_facts |
| role/vars |
| include vars |
| include params |
| extra vars |

---

*文档创建时间：2024年*