Ansible的Playbook的編寫

時間 2020-05-22

標籤 ansible playbook 編寫简体版

原文原文鏈接

在Ansible中，將各個模塊組合起來成爲一個YAML格式的配置文件，這個配置文件叫作Playbook，html

Playbook和模塊的關係相似於shell腳本和Linux命令之間的關係。node

Playbook的定義

一個Playbook能夠包含多個Play，一個Play必須包含:python

hosts 定義在哪些服務器上執行
tasks 定義執行列表，task的語法：module: options

當options較長時能夠採用縮進子塊的形式。mysql

- name: install apachenginx

yum：web

name: apache2sql

state: presentmongodb

一個Playbook能夠使用導入其它的Playbookshell

---apache

- inclued: db.yml

- include: web.yml

使用ansible-playbook執行Playbook

ansible的命令行參數：

-T TIMEOUT, --timeout=TIMEOUT 創建SSH的超時時間
--private-key=PRIVATE_KEY_FILE SSH的私鑰文件
-i INVENTORY, --inventory=INVENTORY 指定inventoey文件
-f FORKS, --forks=FORKS 併發的進程數，默認是5
--list-hosts 匹配到的服務器列表
--list-tasks task列表
--step 每執行一個tasks暫停，等待用戶確認
--syntax-check 檢查palybook的語法
-C, --check 檢查是否會修改遠程服務器，至關於預測執行結果

Playbook定義變量

Ansible有多種定義變量的方法，對於playbook，最簡單的就是定義在Playbook的vars項中;

- hosts
  vars:
    mysql_port: 80

當變量多時，能夠保存在一個獨立的文件中

---
- hosts: all
 vars:
   mysql_prot: 80
 vars_file:
   - /vars/external_vars.yml

變量文件的格式：

---
process: 2000
username: scott

註冊變量

經過register獲取上條命令的執行結果。並在下一個task中引用該變量

- hosts: webservers
  tasks:
     - shell: /usr/bin/foo
       register: foo_result
       ignore_errors: True

     - shell: /usr/bin/bar
       when: foo_result.rc == 5

Facts變量：

在Ansible中有些變量不須要進行任何設置就能直接使用，這些變量叫作Facts變量。

這些變量是Ansible從遠程服務器上獲取的系統信息。

能夠經過setup模塊查看。

ansible webservers -m setup

在Playbook中默認是收集遠程機器信息的，能夠設置爲no，提升Ansible的執行效率。

-- hosts: dbservers

gather_facts: no

循環：

---
- name: Install Mysql package
  yum: name={{ item }} state=installed
  with_items:
    - mysql-server
    - Mysql-python

條件：

---
- hosts: webservers
  tasks:
    - command: echo {{ item }}
      with_items: [ 0,2,4,6,8]
      when: item > 5

　執行結果;

實例：

使用Playbook部署nginx

---
- hosts: webservers
  become: yes
  become_method: sudo
  vars:
    worker_connections: 1024
    worker_processes: 4
    max_open_files: 65506

  tasks:
    - name: install nginx
      yum: name=nginx update_cache=yes state=present

    - name: copy nginx config file
      template: src=/root/study/Ansible/nginx.conf.j2 dest=/etc/nginx/nginx.conf
      notify: restart nginx

    - name: copy index.html
      template:
        src: /root/study/Ansible/index.html.j2
        dest: /usr/share/nginx/www/index.html
        mode: 0644
      notify: restart nginx
      
  handlers:
    - name: restart nginx
      service: name=nginx state=restarted

jinjia2模板文件：

nginx.conf.j2

worker_processes  {{ worker_processes }};
worker_rlimit_nofile {{ max_open_files }};

events {
    worker_connections {{ worker_connections }};
}


http {
    server {
            listen 80 default_server;
            listen [::]:80 default_server ipv6only=on;

            listen 443 ssl;

            root /usr/share/nginx/html;
            index index.html index.htm;

            server_name localhost;

            location / {
                    try_files $uri $uri/ =404;
            }
    }
}

index.html.j2

<html>
  <head>
    <title>Welcome to ansible</title>
  </head>
  <body>
  <h1>nginx, configured by Ansible</h1>
  <p>If you can see this, Ansible successfully installed nginx.</p>

  <p>{{ ansible_hostname }}</p>
  </body>
</html>

訪問主頁;

部署MongoDB

---
- hosts: dbservers
  become: yes
  become_method: sudo
  vars:
    mongodb_datadir_prefix: /data
    mongod_port: 27018

  tasks:
    - name: Create the mongodb user
      user: name=mongodb comment="MongoDB"

    - name: Create the data directory for the namenode metadata
      file: path={{ mongodb_datadir_prefix }} owner=mongodb group=mongodb state=directory

    - name: Install the mongodb package
      apt: name={{ item }} state=installed
      with_items:
        - mongodb-server
        - mongodb-clients
        - rsyslog-mongodb

    - name: create data directory for mongodb
      file:
        path: "{{ mongodb_datadir_prefix }}/mongo-{{ ansible_hostname }}"
        state: directory
        owner: mongodb
        group: mongodb

    - name: create log directory for mongodb
      file: path=/var/log/mongo state=directory owner=mongodb group=mongodb

    - name: Create the mongodb startup file
      template: src=mongod.j2 dest=/etc/init.d/mongod-{{ ansible_hostname }} mode=0655

    - name: Create the mongodb configuration file
      template: src=mongod.conf.j2 dest=/etc/mongod-{{ ansible_hostname }}.conf

    - name: Copy the keyfile for authentication
      copy: src=secret dest={{ mongodb_datadir_prefix }}/secret owner=mongodb group=mongodb mode=0400

    - name: Start the mongodb service
      command: creates=/var/lock/subsys/mongod-{{ ansible_hostname }} /etc/init.d/mongod-{{ ansible_hostname }} start

　　配置文件：mongod.conf.j2

# mongo.conf
smallfiles=true

#where to log
logpath=/var/log/mongo/mongod-{{ ansible_hostname }}.log

logappend=true

# fork and run in background
fork = true

port = {{ mongod_port }}

dbpath={{ mongodb_datadir_prefix }}mongo-{{ ansible_hostname }}
keyFile={{ mongodb_datadir_prefix }}/secret

# location of pidfile
pidfilepath=/var/run/mongod-{{ ansible_hostname }}.pid

另外還能夠將Playbook抽象成role。

能夠參考https://galaxy.ansible.com，下載別人寫好的role

初始化role

ansible-galaxy init /etc/ansible/roles/websrvs

安裝別人寫好的role

ansible-galaxy install -p /etc/ansible/roles bennojoy.mysql