Tasks and Modules (任务与模块) ¶

学习目标

目标：学习如何编写和管理 Ansible 任务以及了解常用的模块。

理解任务（tasks）的基本概念。
学习常用模块的使用方法，如 command、shell、copy、file、yum、apt、service 等。

1. 软件包管理与存储库(YUM 和 APT 模块) ¶

1. yum_repository 模块 ¶

用途：管理 YUM 软件库。

---
- name: Manage yum repositories
  hosts: all
  tasks:
    - name: Add a yum repository
      yum_repository:
        name: epel
        description: EPEL YUM repo
        baseurl: 'https://download.fedoraproject.org/pub/epel/$releasever/$basearch'
        gpgcheck: yes
        enabled: yes

2. apt_repository 模块 ¶

用途：管理 APT 软件库。

---
- name: Manage apt repositories
  hosts: all
  tasks:
    - name: Add an apt repository
      apt_repository:
        repo: 'ppa:deadsnakes/ppa'
        state: present

3. yum 模块 ¶

用途：在 RedHat/CentOS 系统上管理软件包。

---
- name: Ensure software is installed
  hosts: all
  tasks:
    - name: Install Apache
      yum:
        name: httpd
        state: present

4. apt 模块 ¶

用途：在 Debian/Ubuntu 系统上管理软件包。

---
- name: Ensure software is installed
  hosts: all
  tasks:
    - name: Install Apache
      apt:
        name: apache2
        state: present
        update_cache: yes

2. PIP 模块 ¶

1. pip 模块 ¶

用途：管理 Python 包。

---
- name: Ensure software is installed
  hosts: all
  tasks:
    - name: Install Apache
      apt:
        name: apache2
        state: present
        update_cache: yes

3. 文件与目录管理 ¶

1. file 模块 ¶

用途：管理文件和目录的属性（包括权限、所有者等）。

---
- name: Manage file attributes
  hosts: all
  tasks:
    - name: Ensure a directory
      file:
        path: /etc/example
        state: directory
        mode: '0755'

    - name: Ensure a file exists
      file:
        path: /etc/example/config.cfg
        state: touch

    - name: Set file permissions
      file:
        path: /etc/example/config.cfg
        mode: '0644'

2. copy 模块 ¶

用途：将本地文件或目录复制到远程主机。

---
- name: Copy a file to remote
  hosts: all
  tasks:
    - name: Copy configuration file
      copy:
        src: /path/to/local/file
        dest: /path/to/remote/file
        mode: '0644'

3. template 模块 ¶

用途：使用 Jinja2 模板填充并生成配置文件。

---
- name: Template a configuration file
  hosts: all
  tasks:
    - name: Deploy configuration template
      template:
        src: templates/config.cfg.j2
        dest: /etc/someapp/config.cfg

模板文件 (templates/config.cfg.j2)：

[config]
option1 = {{ some_variable }}
option2 = {{ other_variable }}

4. unarchive 模块 ¶

用途：解压缩文件。

---
- name: Extract tar file
  hosts: all
  tasks:
    - name: Extract a tar.gz file
      unarchive:
        src: /tmp/app.tar.gz
        dest: /opt/
        remote_src: yes

5. lineinfile 模块 ¶

用途：确保文件中存在、更新或删除特定的行。

---
- name: Ensure specific line in file
  hosts: all
  tasks:
    - name: Ensure line is present
      lineinfile:
        path: /etc/sysctl.conf
        line: 'net.ipv4.ip_forward = 1'

6. get_url 模块 ¶

用途：从 HTTP、HTTPS 或 FTP 下载文件。

---
- name: Download a file
  hosts: all
  tasks:
    - name: Download from URL
      get_url:
        url: https://example.com/file.tar.gz
        dest: /tmp/file.tar.gz

4. 服务与系统管理 ¶

1. service 模块 ¶

用途：管理服务的状态（启动、停止、重启等）。

---
- name: Manage services
  hosts: all
  tasks:
    - name: Ensure Apache is running
      service:
        name: httpd
        state: started
        enabled: yes

2. user 模块 ¶

用途：管理用户账户。

---
- name: Manage user accounts
  hosts: all
  tasks:
    - name: Ensure user exists
      user:
        name: johndoe
        state: present
        groups: sudo

3. group 模块 ¶

用途：管理用户组。

---
- name: Manage user groups
  hosts: all
  tasks:
    - name: Ensure group exists
      group:
        name: engineers
        state: present

4. hostname 模块 ¶

用途：设置主机名。

---
- name: Set hostname
  hosts: all
  tasks:
    - name: Set system hostname
      hostname:
        name: webserver01

5. cron 模块 ¶

用途：管理 cron 作业。

---
- name: Set up a cron job
  hosts: all
  tasks:
    - name: Ensure cron job is present
      cron:
        name: "Ansible regular task"
        minute: "0"
        hour: "0"
        job: "/usr/bin/example-command"

6. debug 模块 ¶

用途：输出调试信息。

---
- name: Print debug message
  hosts: all
  tasks:
    - name: Show debug message
      debug:
        msg: "This is a debug message"

7. wait_for 模块 ¶

用途：等待某种条件满足，比如端口打开。

---
- name: Wait for something
  hosts: all
  tasks:
    - name: Wait for port 80 to be open
      wait_for:
        port: 80

5. 命令执行 ¶

1. command 模块 ¶

用途：执行命令行命令。

---
- name: Run a command
  hosts: all
  tasks:
    - name: Print current directory
      command: pwd

2. shell 模块 ¶

用途：执行 shell 命令，支持复杂的命令和管道。

---
- name: Run a shell command
  hosts: all
  tasks:
    - name: List all files
      shell: ls -l /var/www

3. git 模块 ¶

用途：管理 Git 版本库。

---
- name: Ensure repository is cloned
  hosts: all
  tasks:
    - name: Clone a repository
      git:
        repo: 'https://github.com/example/repo.git'
        dest: /var/www/repo
        version: 'master'

举个例子 ¶

综合示例，演示如何使用多个核心模块来完成复杂的任务。

---
- name: Comprehensive Example
  hosts: all
  become: yes

  tasks:
    - name: Ensure a directory
      file:
        path: /opt/myapp
        state: directory

    - name: Copy configuration file
      copy:
        src: /path/to/local/config.cfg
        dest: /opt/myapp/config.cfg
        mode: '0644'

    - name: Install nginx
      yum:
        name: nginx
        state: present

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

    - name: Ensure line is present in config
      lineinfile:
        path: /opt/myapp/config.cfg
        line: 'option = value'

    - name: Set up a cron job to restart nginx daily
      cron:
        name: "Daily nginx restart"
        hour: "2"
        minute: "0"
        job: "/usr/bin/systemctl restart nginx"

这个 Playbook 执行了一系列任务：

确保一个目录存在。
复制一个文件到远程主机。
安装 nginx 包。
启动并启用 nginx 服务。
确保配置文件中存在特定的行。
设置一个 cron 作业来每天重启 nginx。

19. firewalld 模块 ¶

用途：管理 Firewalld 服务和规则。

---
- name: Manage Firewalld rules
  hosts: all
  tasks:
    - name: Ensure firewalld is started
      service:
        name: firewalld
        state: started
        enabled: yes

    - name: Open port 80
      firewalld:
        port: 80/tcp
        permanent: yes
        state: enabled
        immediate: yes

20. docker_container 模块 ¶

用途：管理 Docker 容器。

---
- name: Manage Docker containers
  hosts: all
  tasks:
    - name: Start a Docker container
      docker_container:
        name: mycontainer
        image: busybox
        state: started
        command: sleep 1000

21. mysql_db 模块 ¶

用途：管理 MySQL 数据库。

---
- name: Manage MySQL databases
  hosts: all
  tasks:
    - name: Create a MySQL database
      mysql_db:
        name: mydb
        state: present

二、举个例子 ¶

自动化任务：包管理、Git 操作、服务管理、用户管理、文件操作、调试信息输出和计划任务设置。

---
- name: Comprehensive Example with Multiple Modules
  hosts: all
  become: yes

  tasks:
    - name: Ensure necessary packages are installed
      yum:
        name:
          - git
          - nginx
        state: present

    - name: Clone a Git repository
      git:
        repo: 'https://github.com/example/app.git'
        dest: /var/www/html/app

    - name: Start and enable nginx service
      service:
        name: nginx
        state: started
        enabled: yes

    - name: Ensure a user exists
      user:
        name: deploy
        state: present
        groups: wheel

    - name: Create and manage a file
      copy:
        src: files/sample.conf
        dest: /etc/nginx/conf.d/sample.conf
        mode: '0644'

    - name: Print debug message
      debug:
        msg: "Deployment steps completed successfully."

    - name: Set up a cron job for regular updates
      cron:
        name: "Update Job"
        minute: "0"
        hour: "3"
        job: "/usr/local/bin/update.sh"