Ansible automated operation and maintenance --- roles (roles) Detailed, roles httpd service role configuration, system variables Facts of use, batch create user (encryption, decryption), batch configuration / etc / hosts file

A, Ansible role -roles

Role (roles) is a new feature of version 1.2 ansible been introduced for hierarchical, structured organization playbook. Before ansible-playbook all tasks, triggers, variables, and so are written in a document, the content is too long, and not conducive to inspection. And after the introduction of the role, we can put the task, triggers, etc., written main.yml in a specific directory, so more structured, easy to check.

1.1 The directory structure of a role

• default : This directory should contain a main.yml file, used to set the default variable to the current role.
• Files : used to store the file copy module called by the script or module. You do not need to specify the path to the file.
• handlers : This directory should contain a main.yml file that defines the action to perform this role when the trigger condition.
• Meta : This directory should contain a main.yml file that defines the special setting of this role and its dependencies.
• Tasks : This directory should contain a main.yml file, define the task list for this role, this document can be used include contain other task files located in this directory.
• Templates : used to store jinjia2 template, template module will automatically find jinjia2 template files in this directory. You do not need to specify the path to the file.
• VARS : This directory should contain a main.yml file that defines the variables used in this role.

2.1 How to create a role

1、ansible-galaxy command-line tool

• Creating a Role: ansible-galaxy init apache

• You can list current role: ansible-Galaxy List

Two, roles httpd service role configuration

1, ansible.cfg write files under ordinary users devops home directory path defined role is defined as a storage / home / devops / ansible / roles.

[defaults]
inventory = ./hosts
roles_path =./roles  

[privilege_escalation]
become=True
become_method=sudo
become_user=root
become_ask_pass=False

2, create apache:ansible-galaxy init apache

3, editing tasks tasks of main.yml file:vim Tasks / main.yml

4. Edit Trigger handles the main.yml file:vim handlers / main.yml

5, copy the template file to the apache template templates directory, and edit variables added

[devops@server1 apache]$ sudo /etc/httpd/conf/httpd.conf templates/
[devops@server1 apache]$ cd templates/
[devops@server1 templates]$ ls
httpd.conf
[devops@server1 templates]$ mv httpd.conf httpd.conf.j2

6, the definition of variables, editor vim vars / main.yml

• ansible_hostname is a system variable.
  

7, in the file directory, edit the default publishing pages.

[devops@server1 apache]$ cd  files
[devops@server1 apache]$ vim index.html
www.ranran.com

8, New apache.yml file

[devops@server1 ansible]$ vim /home/devops/ansible/apache.yml
---
 - hosts: web
   roles:
     - apache

9, run:ansible-playbook apache.yml

test:

9, redefine the variables in /home/devops/ansible/apache.yml filehttp_port:8080

At this point, run ansible-playbook apache.yml again

Discover the test, still visit 80 ports.

• This is a priority because of the variable.

ansible变量优先级（由高到低）

    ansible-playbook命令中的变量，ansible-playbook -e var=value
    task变量
    block变量
    role中定义的变量和include变量
    set_fact
    registered变量
    vars_files
    var_prompt
    play变量
    host facts
    playbook中设置的host_vars
    playbook中设置的group_vars
    inventory中设置的host_vars
    inventory中设置的group_vars
    inventory变量
    role中defaults/main.yml中定义的变量

去掉写在vars变量目录里的http_port:80，此时apache.yml文件中的变量http_port:8080再次运行就会生效

我们也可以这样编写yaml文件：/home/devops/ansible/apache.yml

• when:只在匹配条件的主机上执行，不匹配的跳过（skipped）
  
  
  

三、Ansible系统变量Facts

ansible中有个特殊的变量，这些变量不是开发者定义的，而是ansible根据目的主机环境信息自动收集的，称之为fact变量。 fact变量很实用，和「when」语句配合使用会让你的代码更加健壮。

• 在执行playbook时，『Gathering Facts 』这一步就是ansible在收集目的主机的facts信息。
• 如果我们定义的playbook中并没有使用到fact变量，那么我们可以选择将其关闭，只需添加「gather_facts: false」即可。

3.1 如何查看系统变量Facts

ansible db -m  setup | grep ipv4  ##过滤出你所需要的变量
ansible db -m  setup | less       ##可在预编译器中查看

3.2 系统变量Facts的使用

1、我们先来写一个包含许多变量的模版info.j2,目的熟悉如何提取变量

主机名：   {{  ansible_facts['hostname'] }}
主机ip：   {{  ansible_facts['default_ipv4']['address'] }}
主机网关：  {{  ansible_facts['default_ipv4']['gateway'] }}
主机DNS：  {{  ansible_facts['dns']['nameservers'][-1] }}
系统内核：  {{  ansible_facts['kernel'] }}
系统版本：  {{  ansible_facts['distribution_file_variety'] }}-{{ ansible_facts['distribution_version'] }}

2、编写一个yml文件，看看提取的变量是否正确 ：vim info.yml

---
- hosts: all
  tasks:
    - name: create /tmp/info
      template:
        src: info.j2
        dest: /tmp/info

3、运行：ansible-playbook info.yml

[root@server2 ~]#  cat /tmp/info
主机名：	server2	
主机ip：	172.25.7.2
主机网关：	172.25.7.250
主机DNS：	114.114.114.114
系统内核：	3.10.0-862.el7.x86_64
系统版本：	RedHat-7.5

[root@server3 ~]# cat /tmp/info
主机名：	server3	
主机ip：	172.25.7.3
主机网关：	172.25.7.250
主机DNS：	114.114.114.114
系统内核：	3.10.0-862.el7.x86_64
系统版本：	RedHat-7.5

四、 批量创建用户（加密、解密）

1、编写yml文件：

2、运行：ansible-playbook users.yml
3、我们可以以此用户连接到本主机：

[root@server1 ~]# ssh user1@172.25.7.1
The authenticity of host '172.25.7.1 (172.25.7.1)' can't be established.
ECDSA key fingerprint is SHA256:5tuDuxoObxbkDCmCJw8bKf4V6ioYDUl7J8I4X3lysKA.
ECDSA key fingerprint is MD5:79:f2:fa:f6:19:27:55:ca:65:74:5b:31:5d:08:fa:b9.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.25.7.1' (ECDSA) to the list of known hosts.
user1@172.25.7.1's password: 
[user1@server1 ~]$

但是此时创建的用户都是相同密码westos，不太安全。我们可以利用字典，一个用户一个密码。

密码以明文的形式存在，也是不安全的。我们可以将用户列表和yaml文件分离开，然后利用ansible自带的加密对userlist进行加密

分离开的用户列表：vim userlist.yml

To encrypt the user list: ansible-vault encrypt userlist.yml, This time using cat to see, to see is a bunch of numbers

• To decrypt user list: ansible-vault decrypt userlist.yml

After the list of users to view encrypted: ansible-vault view userlist.yml

[devops@server1 ansible]$ ansible-vault view userlist.yml
Vault password: 
---
userlist:
  - user: user1
    passwd: ranran 
  - user: ranran
    passwd: cc 
  - user: qiuiqiu
    passwd: baobao

Of course, we can also edit encrypted files: ansible-vault edit userlist.yml ==

when we want to run an encrypted YAML file, to add after the parameter:–ask-vault-pass

ansible-playbook users.yml --ask-vault-pass

V. batch configuration / etc / hosts file

Write your template: vim etc.j2

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
172.25.254.2    foundation2.ilt.example.com

{% for host in group['zabbix'] %}
{{ hostvars[host]['ansible_facts']['eth0']['ipv4']['address'] }}  {{  hostvars[host]['ansible_facts']['hostname'] }}
{% endfor %}

Write etc.yml file, you can run