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介绍

Ansible 是一款能够实现批量系统配置、程序部署、运行命令等功能的自动化运维工具，可以很方便的操作多台服务器。

安装

• 环境

Ubuntu 16.04.1 LTS
ansible 2.9.27

• 更新源

$ apt update

• 安装通用的管理软件库的工具

$ apt install software-properties-common

• 添加 ansible 的源

$ apt-add-repository --yes --update ppa:ansible/ansible

• 再次更新源并安装 ansible

$ apt update && apt install -y ansible

• 查看版本

$ ansible --version
ansible 2.9.27

目前为止，ansible已经安装成功。

配置Inventory

Inventory 默认保存在 /etc/ansible/hosts 配置文件中

• 修改 /etc/ansible/hosts 文件

[local]
127.0.0.1 ansible_ssh_user=ubuntu ansible_ssh_pass=123456
[remote]
121.5.206.236 ansible_ssh_user=ubuntu ansible_ssh_pass=123456

临时命令AD-HOC

• 修改 /etc/ansible/ansible.cfg 文件

host_key_checking = False

去除这一行前面的注释#，禁用 ssh 连接时检查验证 HOST KEY。

• ansible 命令格式

$ ansible 主机名或组名 -m 模块名 -a "模块参数" 其他参数

• 对 local 分组执行命令

$ ansible local -m ping 

• 对 remote 分组执行命令

$ ansible remote -m ping 

• 对所有机器执行命令

$ ansible all -m ping

• 查看 setup 模块中 local 分组机器的信息

$ ansible local -m setup

• remote 组的机器输出 Hello World

$ ansible remote -a "/bin/echo Hello World"

• remote 组中的主机在指定目录下创建文件，并设置权限

$ ansible remote -m file -a "dest=/home/ubuntu/file state=touch mode=777"

• 使用 shell 模块查看所有机器的剩余空间

$ ansible all -m shell -a "free -m"

Playbook语法结构

Playbook 正如它的名字一样，它是一个整的“剧本”，通过系统配置复杂的多机器部署，配置文件默认使用 YAML 格式，更多参考 Playbooks 官方中文文档。

---
# 参数表示一个或多个组或主机，多个时用逗号分隔。
- hosts: remote
# 用户名
  remote_user: root
# 如果需要用 sudo 权限需添加 become: true
  become: true
  vars:
# 对机器实际执行的任务
  tasks:
# 每个任务的名称
    - name: Install the package "bc"
      apt:
        name: bc
        state: present
# handlers只会被执行一次，最佳应用场景是重启服务、触发系统重启操作。
  handlers:
...

编写完 YAML 格式配置文件后，使用 ansible-playbook 命令执行即可ansible-playbook *.yaml。

Ansible模块

“剧本”中会有一幕幕的“演奏”，playbooks 中由多个 plays 组成，plays 也称为 tasks，这些任务就是对 ansible 模块的调用，下面列举几个 ansible 常用模块的示例。

• service 模块示例

# 启动php7.0-fpm服务
---
- hosts: local
  become: true
  tasks:
    - name: make sure php7.0-fpm is running
      service: name=php7.0-fpm state=started
...

# 上面的语句等同于以下写法
---
- hosts: local
  become: true
  tasks:
      - service:
          name: php7.0-fpm
          state: stopped
...

# 安装apache2服务并启动
---
- hosts: local
  become: true

  tasks:
    - name: "Install Apache"
      apt:
        name: apache2
        state: present
    - name: "Startup Apache"
      service:
        name: apache2
        state: started
        enabled: yes
...

• shell 模块示例

# 下载并安装redis服务
---
- hosts: remote
  become: true
  tasks:
    - name: make download redis
      shell: git clone https://hub.fastgit.xyz/phpredis/phpredis.git
    - name: make install redis
      shell: /usr/bin/phpize7.0 && ./configure --with-php-config=/usr/bin/php-config && make && make install
      args:
          chdir: /home/ubuntu/phpredis
...

# 在指定目录下创建一个文件，并赋予权限
---
- hosts: remote
  become: true
  tasks:
    - name: create a file
      file:
           path: /home/ubuntu/file
           state: touch
           owner: ubuntu
           mode: 'u+rw,g+rw'
...

# 复制一个文件到指定目录
---
- hosts: remote
  become: true
  tasks:
    - name: copy a file
      copy:
        src: /etc/nginx/sites-available/default
        dest: /etc/nginx/sites-available/yuhal.com
...

# 安装docker
---
- hosts: local
  become: true
  vars:
      ansible_python_interpreter: /usr/bin/python3

  tasks:
    - name: Install aptitude using apt
      apt: name=aptitude state=latest update_cache=yes force_apt_get=yes

    - name: Install required system packages
      apt: name={{ item }} state=latest update_cache=yes
      loop: [ 'apt-transport-https', 'ca-certificates', 'software-properties-common']

    - name: add apt-key of dockers
      apt_key:
          url: https://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg
          state: present

    - name: Add Docker Repository
      apt_repository:
        repo: deb [arch=amd64] https://mirrors.aliyun.com/docker-ce/linux/ubuntu xenial stable
        state: present

    - name: Update apt and install docker-ce
      apt: update_cache=yes name=docker-ce state=latest
...

Playbook执行控制

• 判断

# 当变量switch为true时执行shell
---
- hosts: remote
  become: true
  vars:
      switch: true
  tasks:
    - shell: echo "The switch is on"
      when: switch
...

# 当item>5时打印输出
---
- hosts: local

  tasks:
      - name: condition
        command: echo {{ item }}
        with_items: [ 0, 2, 4, 6, 8, 10 ]
        when: item > 5
...

• 标准循环

# 添加多个用户
---
- hosts: remote
  become: true
  tasks:
    - name: add several users
      user:
        name: "{{ item }}"
        state: present
        groups: "ubuntu"
      with_items:
         - user1
         - user2
...

# 上面的语句等同于以下写法
---
- hosts: remote
  become: true
  tasks:
    - name: add user user3
      user:
        name: "user3"
        state: present
        groups: "ubuntu"
    - name: add user user4
      user:
        name: "user4"
        state: present
        groups: "ubuntu"
...

• 嵌套循环

# 设置用户访问多个数据库
---
- hosts: remote
  become: true
  vars:
      item: []
  tasks:
    - name: give users access to multiple databases
      mysql_user:
        name: "{{item[0]}}"
        priv: "{{item[1]}}.*:ALL"
        append_privs: yes
        password: "123456"
      with_nested:
        - ['dbuser1','dbuser2']
        - ['mysql','sys']
...

Ansible调试

• debug 模块

---
- hosts: local
  tasks:
     - name: user register
       shell: echo $PATH
       register: user
     - debug: msg={{user}}
...

• plugins 插件

借助 plugins 可以更方便的显示 debug 信息，可以在配置文件 /etc/ansible/ansible.cfg 中查看有哪些插件。

# set plugin path directories here, separate with colons
#action_plugins     = /usr/share/ansible/plugins/action
#become_plugins     = /usr/share/ansible/plugins/become
#cache_plugins      = /usr/share/ansible/plugins/cache
#callback_plugins   = /usr/share/ansible/plugins/callback
#connection_plugins = /usr/share/ansible/plugins/connection
#lookup_plugins     = /usr/share/ansible/plugins/lookup
#inventory_plugins  = /usr/share/ansible/plugins/inventory
#vars_plugins       = /usr/share/ansible/plugins/vars
#filter_plugins     = /usr/share/ansible/plugins/filter
#test_plugins       = /usr/share/ansible/plugins/test
#terminal_plugins   = /usr/share/ansible/plugins/terminal
#strategy_plugins   = /usr/share/ansible/plugins/strategy

这些插件在 GitHub 中是公开的，可以直接克隆下来，下面举例下载 action_plugins 插件。

• 下载 action_plugins 插件

$ git clone https://github.com/n0ts/ansible-human_log.git

• 查看 ansible-human_log 目录

$ ls ansible-human_log
human_log.py  README.md

• 将 human_log.py 复制到 callback_plugins 预定义的插件位置

$ mkdir -p /usr/share/ansible/plugins/callback
$ mv ansible-human_log/human_log.py /usr/share/ansible/plugins/callback/human_log.py

插件安装完成后，再次执行之前的 yaml，就可以看到返回的 msg 信息啦。