1. Getting Started with Ansible

安装

yum安装

yum install ansible

pip安装

pip install ansible

Hello Ansible

创建资产文件（inventory）

[servers]
192.168.137.3 ansible_ssh_user='root' ansible_ssh_pass='123456'
192.168.137.4 ansible_ssh_user='root' ansible_ssh_pass='123456'

servers是一个组名称，可以把具有相同用途的机器归为同一个组，例如：
[mysql_servers]
在安装MySQL时只需指定这个组安装:
ansible -i inventory mysql_servers -m shell -a 'yum install mysql'

ansible常用参数

-a MODULE_ARGS, --args=MODULE_ARGS
    eg: ansible -i inventory 192.168.137.4 -m shell -a 'echo haha'
          模块shell 之后带的参数

-i INVENTORY, --inventory-file=INVENTORY
    指定资产文件

-m MODULE_NAME, --module-name=MODULE_NAME
    指定模块，如上面的shell模块

使用ansible

资产文件inventory中 servers 组内所用机器执行 ping 模块，测试机器状态。

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资产文件inventory中 servers 组内所用机器执行 shell 模块，并使用besty用户执行 echo 命令。

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Configuring Ansible （配置ansible）

ansible使用 INI 配置

INI配置格式（参考MySQL）
[section]
key = value

配置文件的选择 （按以下顺序加载配置文件）
- ANSIBLE_CONFIG （Firstly）
export ANSIBLE_CONFIG="/data/ansible/ansible.cfg"
配置文件就是：/data/ansible/ansible.cfg
- ./ansible.cfg (Secondly)
若无 ANSIBLE_CONFIG 环境变量，配置文件优先选择当前目录的 ansible.cfg
- ~/.ansible.cfg (Thirdly)
家目录下的 .ansible.cfg，注意是隐藏文件
- /etc/ansible/ansible.cfg (Lastly)
用软件包管理工具(yum/apt/dnf/pip)安装时自动生成
Configuration using environment variables (使用环境变量配置)

export ANSIBLE_SUDO_USER=root
The ANSIBLE_SUDO_USER variable can then be used as part of the playbooks.
定义的 ANSIBLE_SUDO_USER 变量就能在 playbooks中使用了
Configuration using ansible.cfg
- hostfile
This parameter indicates the path to the inventory file
默认的inventory文件：
hostfile = /etc/ansible/hosts
- library
The library parameter points to the path of the directory where Ansible modules are stored
自定义模块的存储路径，默认：
library = /usr/share/ansible
- forks
This parameter is the default number of processes that you want Ansible to spawn
ansible执行时打开的最大进程数： forks = 5
- remote_port
远程机器的的ssh端口: remote_port = 22
- timeout
This is the default value for the timeout of SSH connection attempts:
timeout = 60
- log_path
日志存储路径
log_path = /var/log/ansible.log

Working with playbooks

playbooks 是一个to-do list，包含了远程需要执行的任务列表，每个任务会调用一个模块，用 yaml 编写
http://www.ruanyifeng.com/blog/2016/07/yaml.html

playbooks编写

playbooks/setup_apache.yml

- hosts: servers
  remote_user: root
  tasks:

   - name: install httpd package
     yum: name=httpd state=latest
     sudo: yes

   - name: start httpd
     service: name=httpd state=started
     sudo: yes

   - name: echo ANSIBLE_SUDO_USER
     shell: echo "The sudo user is {{ lookup('env','ANSIBLE_SUDO_USER') }}" > /data/user
     sudo: yes

ANSIBLE_SUDO_USER是之前定义的环境变量： export ANSIBLE_SUDO_USER=root

一个playbook包含如下三个部分：

hosts：指定要执行任务的是那些机器，这里是 [server] 组

remote_user: 被管理机器执行任务时使用的用户

tasks: 任务列表（to-do list）, 本例安装 httpd 服务并启动, name参数可选, 推荐下面这种写法：

tasks:
  - yum: name=httpd state=latest
    sudo: yes
  - service: name=httpd state=started
    sudo: yes

执行ansible-playbook

# ansible-playbook -i hosts playbooks/setup_apache.yml
playbooks 具有 幂等性（Idempotency），即执行多次和执行一次达到的状态（state）是一样的.
可以理解为：1 ⁿ = 1
-v 选项输出更详细的信息，可叠加3个 -v/-vv/-vvv

image.png

系统自带变量使用

- debug: msg={{ ansible_distribution }}
  sudo: yes

列出playbook所有任务

ansible-playbook -i hosts playbooks/setup_apache.yml --list-tasks

执行任务前询问

ansible-playbook -i hosts playbooks/setup_apache.yml --step

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playbooks variables

变量设置
Variables in an included task file

# cat playbooks/install_apache.yml
- set_fact: package_name=httpd
  when: ansible_os_family == "RedHat"

- set_fact: package_name=apache2
  when: ansible_os_family == "Debian" 

# cat playbooks/setup_apache.yml
- hosts: servers
  remote_user: root
  tasks:
    - include: /data/ansible/playbooks/install_apache.yml

    - yum: name={{ package_name }} state=latest
      sudo: yes

    - service: name={{ package_name }} state=started
      sudo: yes

setup_apache.yml 真正用于执行任务，使用 include 模块导入playbooks/install_apache.yml文件
Variables in a playbook

# cat playbooks/setup_apache.yml
- hosts: servers
  remote_user: root
  vars:
    - package_name: httpd
  tasks:
    - yum: name={{ package_name }} state=latest
      sudo: yes

Variables in a global file

# cat playbooks/var1.yml
---
package_name: "apache2"

# cat playbooks/var2.yml
---
package_name: "httpd"

# cat playbooks/setup_apache.yml
- hosts: servers
  remote_user: root
  vars_files:
    - var1.yml
    - var2.yml
  tasks:
    - yum: name={{ package_name }} state=latest
      sudo: yes

You tell Ansible which variable files need to be checked by using the vars_files key, vars_files 键值对，查找变量时顺序从下到上，先在 var2.yml 查找是否有 package_name 变量，若找到则使用 var2.yml定义的变量值，找不到则在 var1.yml 中查找

Facts as variables （可理解为常量）

ansible 192.168.137.4 -m setup

image.png

Command-line variables
执行命令时赋值

ansible-playbook -i hosts playbooks/apache.yml --extra-vars "package_name=apache2"

Working with inventory files

Groups of groups

具有相同用途或者需要执行相同模块指令的机器可以归类为一个组
[db]
192.168.137.4
mysql_host

[application]
192.168.137.3
web.com

安装MySQL时执行以下命令

ansible db -i hosts -m shell "yum install mysql"

Regular expressions with an inventory file

使用正则表达式
[db]
192.168.137.[2:4]
#表示 db 组有192.168.137.2-43 台机器

Inventory Variables

在资产文件中定义变量
# 主机变量
[db]
192.168.137.4 dbname='game'

# 组变量，整个组都能使用
[db:vars]
dbport="3306"
dbname="game"

#以上变量在playbook能够使用

Overriding configuration parameters with an inventory file
inventory 文件中定义变量覆盖配置文件中的参数
- ansible_ssh_user: 相当于 ssh {{ ansible_ssh_user }}@1.1.1.1
- ansible_ssh_port: 远程主机的 SSH 端口
- ansible_ssh_host: 连接远程主机时所用的实际地址，相当于 ssh {{ ansible_ssh_host }}
- ansible_connection: 连接类型 SSH/paramiko/local 3种选择，默认为SSH
- ansible_ssh_private_key_file: 指定远程认证的私钥，默认为 ~/.ssh/id_rsa
- ansible_shell_type: shell类型 csh/zsh/ksh/bash
- ansible_python_interpreter: python解释器，默认为 /usr/bin/python

Working with modules

command modules

command

- name: Backup a file
  command: cp /etc/httpd/conf/httpd.conf /data/httpd.conf

raw

在没有安装python的环境远程执行任务时使用，可用于路由器/交换机

- name: Install vim
   raw: yum -y install vim-common
   sudo: yes

script

- name: run a script 
  script: test.sh

# cat playbooks/test.sh
ls /etc/ | grep '^d' | wc -l

shell

- name: List files in /tmp and redirect to a file
  shell: /bin/ls -l /tmp > /tmp/list

File modules

file

- name: Ensure httpd conf has right permissions and owner/group
  file: path=/etc/httpd/conf/httpd.conf owner=root group=root mode=0644

- name: Create a symlink in /tmp for httpd.conf
  file: src=/etc/httpd/conf/httpd.conf dest=/tmp/httpd.conf owner=root group=root state=link

template

template 模块用于生成 jinja2 模板文件， 创建 jinja2 模板：
# cat playbooks/test.jinja2
The os_family is {{ ansible_os_family }}

- name: Create a test template
  template: src=test dest=/tmp/testfile mode=644

# cat /tmp/testfile
The os_family is RedHat

jinja2学习文档

copy

- name: Copy file remotely
  copy: src=test2.conf dest=/etc/test2.conf owner=root group=root mode=0644

1. Getting Started with Ansible

安装

Hello Ansible

Configuring Ansible （配置ansible）

Working with playbooks

Working with inventory files

Working with modules

command modules

File modules

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