Article Directory
1. Overview of playbooks and example operations
1. The composition of playbooks
The playbooks themselves consist of the following parts
(1) Tasks: Tasks, that is, calling ansible templates through tasks to organize multiple operations in a playbook
(2) Variables: variables
(3) Templates: template
(4) Handlers: Processor, when the changed state condition is met, (notify) triggers the execution of the operation
(5) Roles: role
2. Operation example 1:
2.1 Write the yaml file, which is the playbook
vim test1.yaml
--- #yaml文件以---开头，以表明这是一个yaml文件，可省略
- name: first play #定义一个play的名称，可省略
gather_facts: false #设置不进行facts信息收集，这可以加快执行速度，可省略
hosts: webservers #指定要执行任务的被管理主机组，如多个主机组用冒号分隔
remote_user: root #指定被管理主机上执行任务的用户
tasks: #定义任务列表，任务列表中的各任务按次序逐个在hosts中指定的主机上执行
- name: test connection # 自定义任务名称
ping: #使用 module: [options] 格式来定义一个任务
- name: disable selinux
command: '/sbin/setenforce 0' #command模块和shell模块无需使用key=value格式
ignore_errors: True #如执行命令的返回值不为0，就会报错，tasks停止，可使用ignore_errors忽略失败的任务
- name: disable firewalld
service: name=firewalld state=stopped #使用 module: options 格式来定义任务，option使用key=value格式
- name: install httpd
yum: name=httpd state=latest
- name: install configuration file for httpd
copy: src=/opt/httpd.conf dest=/etc/httpd/conf/httpd.conf #这里需要一个事先准备好的/opt/httpd.conf文件
notify: "restart httpd" #如以上操作后为changed的状态时，会通过notify指定的名称触发对应名称的handlers操作
- name: start httpd service
service: enabled=true name=httpd state=started
handlers: #handlers中定义的就是任务，此处handlers中的任务使用的是service模块
- name: restart httpd #notify和handlers中任务的名称必须一致
service: name=httpd state=restarted
##Ansible在执行完某个任务之后并不会立即去执行对应的handler，而是在当前play中所有普通任务都执行完后再去执行handler，这样的好处是可以多次触发notify，但最后只执行一次对应的handler，从而避免多次重启。
2.2 Modify the configuration file and put it in the /opt/ directory
vim httpd.conf #在/opt/目录下放入修改之后的配置文件
#42行，指定端口
Listen 8080
#95行，指定域名
ServerName www.ly.com:8080
2.3 run playbook
ansible-playbook test1.yaml
//补充参数：
-k（–ask-pass）：用来交互输入ssh密码
-K（-ask-become-pass）：用来交互输入sudo密码
-u：指定用户
ansible-playbook test1.yaml --syntax-check #检查yaml文件的语法是否正确
ansible-playbook test1.yaml --list-task #检查tasks任务
ansible-playbook test1.yaml --list-hosts #检查生效的主机
ansible-playbook test1.yaml --start-at-task='install httpd' #指定从某个task开始运行
3. Operation example 2: define and reference variables
- name: second play
hosts: dbservers
remote_user: root
vars: #定义变量
- groupname: mysql #格式为 key: value
- username: nginx
tasks:
- name: create group
group: name={
{
groupname}} system=yes gid=306 #使用 {
{key}} 引用变量的值
- name: create user
user: name={
{
username}} uid=306 group={
{
groupname}}
- name: copy file
copy: content="{
{ansible_default_ipv4}}" dest=/opt/vars.txt #在setup模块中可以获取facts变量信息
ansible-playbook test2.yaml -e "username=nginx" #在命令行里定义变量
4. Operation example 3: Specify remote host sudo to switch users
---
- hosts: dbservers
remote_user: zhangsan
become: yes #2.6版本以后的参数，之前是sudo，意思为切换用户运行
become_user: root #指定sudo用户为root
执行playbook时：ansible-playbook test3.yml -K <密码>
5. Operation example 4: when condition judgment
In Ansible, the only general condition judgment provided is the when instruction. When the value of the when instruction is true, the task is executed, otherwise the task is not executed.
//when A common application scenario is to skip a host that does not execute tasks or only hosts that meet the conditions execute tasks
vim test4.yaml
---
- hosts: all
remote_user: root
tasks:
- name: shutdown host
command: /sbin/shutdown -r now
when: ansible_default_ipv4.address == "192.168.229.80" #when指令中的变量名不需要手动加上 {
{}}
或
when: inventory_hostname == "<主机名>"
ansible-playbook test4.yaml
6. Operation example: Five: Iteration
Ansible provides a variety of loop structures, generally named with_items, which is equivalent to the loop loop.
vim test5.yaml
---
- name: play5
hosts: dbservers
gather_facts: false
tasks:
- name: create directories ##创建目录。目录名使用with_items里的循环
file:
path: "{
{item}}" ##由于值是{
{....}} ,所以为了防止被认为是字典，要加上双引号.
state: directory
with_items: #等同于 loop:
- /tmp/test1
- /tmp/test2
- name: add users ###使用循环创建用户，并添加附加组
user: name={
{
item.name}} state=present groups={
{
item.groups}}
with_items:
- name: test1
groups: wheel
- name: test2
groups: root
或
with_items:
- {
name:'test1', groups:'wheel'}
- {
name:'test2', groups:'root'}
ansible-playbook test5.yaml
Two, playbook module
1. Templates module
Jinja is a Python-based templating engine. The Template class is an important component of Jinja, which can be regarded as a compiled template file, used to generate target text, and pass Python variables to the template to replace the tags in the template.
1.1. First prepare a template template file with the suffix .j2, and set the referenced variables
cp /etc/httpd/conf/httpd.conf /opt/httpd.conf.j2
vim /opt/httpd.conf.j2
Listen {
{
http_port}} #42行，修改
ServerName {
{
server_name}} #95行，修改
DocumentRoot "{
{root_dir}}" #119行，修改 <Directory "{
{root_dir}}"> #131修改 配置目录访问权限
1.2. Modify the host list file, use the host variable to define a variable with the same variable name but different values
vim /etc/ansible/hosts
[webservers]
192.168.229.80 http_port=192.168.229.80:80 server_name=www.ly.com:80 root_dir=/etc/httpd/htdocs
[dbservers]
192.168.229.70 http_port=192.168.229.70:80 server_name=www.weq.com:80 root_dir=/etc/httpd/htdocs
1.3. Write playbook
vim apache.yaml
---
- hosts: all
remote_user: root
vars:
- package: httpd
- service: httpd
tasks:
- name: install httpd package
yum: name={
{
package}} state=latest
- name: install configure file
template: src=/opt/httpd.conf.j2 dest=/etc/httpd/conf/httpd.conf #使用template模板
notify:
- restart httpd
- name: create root dir
file: path=/etc/httpd/htdocs state=directory
- name: start httpd server
service: name={
{
service}} enabled=true state=started
handlers:
- name: restart httpd
service: name={
{
service}} state=restarted
ansible-playbook apache.yaml
1.4 Make a test page
ansible 192.168.229.80 -m shell -a "echo 'this is ly template test' > /etc/httpd/htdocs/index.html" #制作网页测试文件
ansible 192.168.229.70 -m shell -a "echo 'this is weq template test' > /etc/httpd/htdocs/index.html"<br><br>curl http://192.168.229.80 #登录访问查看<br><br>curl http://192.168.229.70<br>
2. tags module
You can define "tags" for one or some tasks in a playbook. When executing this playbook, use the –tags option through the ansible-playbook command to run only the specified tasks.
The playbook also provides a special tags for always. The effect is that when using always as the task of tags, no matter which tags are executed, the tags defined with always will be executed.
vim webhosts.yaml
---
- hosts: webservers
remote_user: root
tasks:
- name: Copy hosts file
copy: src=/etc/hosts dest=/opt/hosts
tags:
- only #可自定义
- name: touch file
file: path=/opt/testhost state=touch
tags:
- always #表示始终要运行的代码
ansible-playbook webhosts.yaml --tags="only"
vim dbhosts.yaml
---
- hosts: dbservers
remote_user: root
tasks:
- name: Copy hosts file
copy: src=/etc/hosts dest=/opt/hosts
tags:
- only
- name: touch file
file: path=/opt/testhost state=touch
ansible-playbook dbhosts.yaml --tags="only"
Go to the two managed hosts to check the file creation status
3. Roles module
Ansible uses roles to organize Playbooks hierarchically and structurally. Roles can automatically load variable files, tasks, and handlers according to the hierarchical structure. Simply put, roles is to place variables, files, tasks, modules and processors in separate directories, and easily include them. Roles are generally used in scenarios where services are built based on hosts, but they can also be used in scenarios such as building daemons.
3.1 Directory structure of roles:
cd /etc/ansible/
tree roles/
roles/
├── web/
│ ├── files/
│ ├── templates/
│ ├── tasks/
│ ├── handlers/
│ ├── vars/
│ ├── defaults/
│ └── meta/
└── db/
├── files/
├── templates/
├── tasks/
├── handlers/
├── vars/
├── defaults/
└── meta/
3.2 Explanation of the meaning of each directory in roles
●files
is used to store the files invoked by the copy module or script module.
●templates
is used to store jinjia2 templates, and the template module will automatically search for jinjia2 template files in this directory.
●tasks
This directory should contain a main.yml file, which is used to define the task list of this role. This file can use include to include other task files located in this directory.
●handlers
This directory should contain a main.yml file, which is used to define the action to be executed when the condition is triggered in this role.
●vars
This directory should contain a main.yml file that defines the variables used by this role.
●defaults
This directory should contain a main.yml file, which is used to set default variables for the current role.
●meta
This directory should contain a main.yml file, which is used to define the special settings and dependencies of this role.
3.3 Steps to use roles in a playbook:
(1) Create a directory named after roles
mkdir /etc/ansible/roles/ -p #yum装完默认就有
(2) Create a global variable directory (optional)
mkdir /etc/ansible/group_vars/ -p
touch /etc/ansible/group_vars/all #文件名自己定义，引用的时候注意
(3) In the roles directory, create directories commanded by each role name, such as httpd, mysql
mkdir /etc/ansible/roles/httpd
mkdir /etc/ansible/roles/mysqlmkdir /etc/ansible/roles/php
(4) Create files, handlers, tasks, templates, meta, defaults and vars directories in the directory of each role command. The directories that are not used can be created as empty directories or not created
mkdir /etc/ansible/roles/httpd/{
files,templates,tasks,handlers,vars,defaults,meta}
mkdir /etc/ansible/roles/mysql/{
files,templates,tasks,handlers,vars,defaults,meta}<strong><br></strong>mkdir /etc/ansible/roles/php/{
files,templates,tasks,handlers,vars,defaults,meta}
(5) Create a main.yml file in the handlers, tasks, meta, defaults, and vars directories of each role, and never customize the file name
touch /etc/ansible/roles/httpd/{
defaults,vars,tasks,meta,handlers}/main.yml
touch /etc/ansible/roles/mysql/{
defaults,vars,tasks,meta,handlers}/main.ymltouch /etc/ansible/roles/php/{
defaults,vars,tasks,meta,handlers}/main.yml
(6) Modify the site.yml file to call different roles for different hosts
vim /etc/ansible/site.yml
---
- hosts: webservers
remote_user: root
roles:
- httpd
- hosts: dbservers
remote_user: root
roles:
- mysql
sample template
(7) Run ansible-playbook
cd /etc/ansible
ansible-playbook site.yml
has not yet prepared the writing of the yml file for roles
3. Application of roles in LAMP
Follow the above experimental steps
1. Write the httpd module
Write a simple tasks/main.yml
vim /etc/ansible/roles/httpd/tasks/main.yml
- name: install apache
yum: name={
{
pkg}} state=latest
- name: start apache
service: enabled=true name={
{
svc}} state=started
//Define variables: can be defined in global variables, or in roles role variables, generally defined in role variables
vim /etc/ansible/roles/httpd/vars/main.yml
pkg: httpd
svc: httpd
Here we define in the role variable
2. Write the mysql module
vim /etc/ansible/roles/mysql/tasks/main.yml
- name: install mysql
yum: name={
{
pkg}} state=latest
- name: start mysql
service: enabled=true name={
{
svc}} state=started
vim /etc/ansible/roles/mysql/vars/main.yml
pkg:
- mariadb
- mariadb-server
svc: mariadb
3. Write php module
vim /etc/ansible/roles/php/tasks/main.yml
- name: install php
yum: name={
{
pkg}} state=latest
- name: start php-fpm
service: enabled=true name={
{
svc}} state=started
vim /etc/ansible/roles/php/vars/main.yml
pkg:
- php
- php-fpm
svc: php-fpm
4. Write an example of roles
vim /etc/ansible/site.yml
---
- hosts: webservers
remote_user: root
roles:
- httpd
- mysql
- php
cd /etc/ansible
ansible-playbook site.yml
