day52-Ansible-variables

1.什么是变量？

以一个固定的字符串，表示一个不固定的值

2.定义变量

（1）在playbook中定义变量
①vars关键字
例题：

[root@manager project1]# cat f2.yml 
- hosts: webservers
  vars:
    - file_name: playbook_vars

  tasks:
    - name: Create New File
      file:
        path: /tmp/{{ file_name }}
        state: touch

②vars_file

QQ图片20191011194937.png

例题：

[root@manager project1]# cat vars_file.yml 
web_packages: httpd
ftp_packages: vsftpd

[root@manager project1]# cat f2.yml 
- hosts: webservers
  vars:
    - file_name: playbook_vars

 #调用共享vars_file文件,只不过刚好文件名叫vars_file
  vars_files: ./vars_file.yml

  tasks:
    - name: Create New File
      file:
        path: /tmp/{{ file_name }}
        state: touch

    - name: Installed Packages {{ web_packages }}
      yum:
        name: "{{ web_packages }}"
        state: present

（2）在inventory主机清单中定义变量
①清单文件中直接定义(hosts文件中定义）

[webservers]
172.16.1.7
172.16.1.8 
[webservers:vars]
file_name=hostsfile_group_vars

②准备hosts_vars group_vars目录
例题：

[root@manager project1]# mkdir hosts_vars   #单个主机
[root@manager project1]# mkdir group_vars   #主机组


#1.单个主机定义和使用方式 (host_vars能分别对不同的主机定义变量)
[root@manager project1]# cat host_vars/172.16.1.7 
host_vars_name: 172.16.1.7

[root@manager project1]# cat host_vars/172.16.1.8 
host_vars_name: 172.16.1.8

[root@manager project1]# cat f4.yml 
- hosts: webservers

  tasks:
    - name: Create New File
      file:
        path: /opt/{{ host_vars_name }}
        state: touch

#2.针对主机组定义的方式 
#给指定的webserver组设定变量.其他组主机无法使用该变量
[root@manager project1]# cat group_vars/webservers 
group_host_vars: webservers

[root@manager project1]# cat f5.yml 
- hosts: webservers
  tasks:
    - name: Create New File {{ group_host_vars }}
      file:
        path:  /opt/{{ group_host_vars }}
        state: touch


#3.针对主机组定义的方式  (给所有的主机和主机组设定变量)
[root@manager project1]# cat group_vars/all 
group_host_vars: all

[root@manager project1]# cat f5.yml 
- hosts: webservers
  tasks:
    - name: Create New File {{ group_host_vars }}
      file:
        path:  /opt/{{ group_host_vars }}
        state: touch

（3）通过外置传参定义变量-e
例题：

[root@manager project1]# ansible-playbook -i hosts f6.yml  -e "web_vars=123"

3.变量冲突，优先级
（1）定义相同的变量不同的值，来测试变量的优先级。
操作步骤如下：file_name

①在plabook中定义vars变量
②在playbook中定义vars_files变量
③在inventory主机定义变量
④在inventory主机组定义变量
⑤在host_vars中定义变量
⑥在group_vars中定义变量  组      all组
⑦通过执行命令传递变量

（2）优先级测试总结
外置传入参数优先级最高---->playbook(vars_files[共享]---->vars[私有])---->host_vars--->group_vars/group_name--->group_vars/all

4.变量注册

例题：

[root@manager project1]# cat f8.yml 
- hosts: webservers
  tasks:
        # System_Status=$(netstat -lntp)
    - name: Get Network Status
      shell: netstat -lntp | grep "nginx"
      register: System_Status

        # echo "$System_Status"
    - name: Debug output Variables
      debug:
        msg: "{{
System_Status.stdout_lines }}"

5.facts变量

ansible facts是在被管理主机上通过ansible自动采集发现的变量。facts包含每台特定的主机信息

• facts使用的场景

  
  
  

  Image fas.png

（1）根据主机的cpu信息，生成不同的配置
A: 1核心 work_process 1;
B: 2核心 work_process 2;

[root@manager project1]# cat f10.yml
- hosts: webservers
  tasks:
    - name: Configure Nginx.conf
      template:
        src: ./file/nginx.conf.j2
        dest: /etc/nginx/nginx.conf
[root@manager project1]# cat ./file/nginx.conf.j2
user www;
worker_processes  {{ ansible_processor_vcpus }};

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;

events {
    worker_connections  {{ ansible_processor_vcpus*1024 }};
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /var/log/nginx/access.log main;

    sendfile        on;
    #tcp_nopush     on;
    keepalive_timeout  65;
    #gzip  on;
    include /etc/nginx/conf.d/*.conf;
}

[root@manager project1]#
（2）根据主机名称设定不同配置文件
zabbix_agent
Server: ===> 指向172.16.1.61
Hostname: web01 web02

[root@manager project1]# cat ./file/zabbix_agent.conf.j2 
Server={{ zabbix_server_ip }}
ServerActive={{ zabbix_server_ip }}
Hostname={{ ansible_hostname }}

[root@manager project1]# cat f11.yml 
- hosts: webservers
  vars:
    - zabbix_server_ip: 172.16.1.61
  tasks:
    - name: Configure zabbix-agent.conf
      template:
        src: ./file/zabbix_agent.conf.j2
        dest: /tmp/zabbix-agent.conf

（3）3.根据主机的内存生成不同的配置文件,memcached

[root@manager project1]# cat f12.yml 
- hosts: webservers
  tasks:
    - name: Installed Memcached Server
      yum:
        name: memcached
        state: present

    - name: Configure Memcached Server
      template:
        src: ./file/memcached.j2
        dest: /etc/sysconfig/memcached
      notify: Restart Memcached Server

    - name: System Memcached Server
      systemd:
        name: memcached
        state: started
        enabled: yes

  handlers:
    - name: Restart Memcached Server
      systemd:
        name: memcached
        state: restarted

[root@manager project1]# cat file/memcached.j2 
PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="{{ ansible_memtotal_mb //2 }}"
OPTIONS=""

ff.png

（4）使用ansible批量修改200台主机的主机名称？（名称必须随机，没有任何规律）

[root@manager project1]# cat f13.yml 
- hosts: webservers
  tasks:
    - name: RANDOM
      shell:  echo "$RANDOM"
      register: System_SJ

    - name: Debug 
      debug:
        msg: "web_{{ System_SJ.stdout }}"

#1.提取facts变量中的IP地址   mac地址  UUID 等等  只要唯一
    ansible_default_ipv4.address
[root@manager project1]# cat f14.yml 
- hosts: webservers
  tasks:

    - name: Debug 
      debug:
        msg: "web_{{ ansible_default_ipv4.address }}"

Ansible流程控制

6.判断语句

• （1）.centos和ubuntu系统都需要安装httpd, 判断系统.
• （2）.安装软件仓库,只有web组的安装webtatic其他的主机全部跳过.
• （3）.TASK任务, TASK1任务执行成功,才会执行TASK2
  例题：
  （1）根据不同的系统,安装不同的服务

- hosts: webservers
  tasks:
    - name: CentOS Installed Httpd Server
      yum:
        name: httpd
        state: present
      when: ( ansible_distribution == "CentOS" )

    - name: Ubuntu Installed Httpd Server
      yum:
        name: httpd2
        state: present
      when: ( ansible_distribution == "Ubuntu" )
      
[root@manager project1]# cat f16.yml 
- hosts: all
  tasks:
  - name: Add Nginx Yum Repository
    yum_repository:
      name: nginx
      description: Nginx Repository
      baseurl: http://nginx.org/packages/centos/7/$basearch/
    when: ( ansible_hostname is match ("web*"))


[root@manager project1]# cat f17.yml 
- hosts: webservers
  tasks:

    - name: Check Httpd Server
      command: systemctl is-active httpd
      register: Check_Httpd
      ignore_errors: yes

    #判断Check_Httpd.rc是否等于0,如果为0则执行任务,否则不执行
    - name: Restart Httpd Server
      systemd:
        name: httpd
        state: restarted
      when: ( Check_Httpd.rc == 0 )

7.循环语句

例题：
（1）一次启动多个服务

[root@manager project1]# cat f18.yml 
- hosts: webservers
  tasks:
    - name: Systemd Nginx Status
      systemd:
        name: "{{ item }}"    #调用的变量也不变,也是固定
        state: started

    #固定的语法格式
      with_items:
        - nginx
        - php-fpm

（2）一次拷贝多个文件

[root@manager project1]# cat f19.yml
- hosts: webservers
  tasks:
    - name: Configure nginx.conf
      copy:
        src: '{{ item.src }}'
        dest: '{{ item.dest }}'
        mode: '{{ item.mode }}'
      with_items:
        - { src: ./file/nginx.conf.j2, dest: /etc/nginx/nginx.conf, mode: '0644' }
        - { src: ./file/kold.oldxu.com.conf.j2, dest: /etc/nginx/conf.d/kold.oldxu.com.conf, mode: '0600' }

（3）创建多个用户,一次创建多个? 3个用户

[root@manager project1]# cat f20.yml 
- hosts: webservers
  tasks:
    - name: Create User
      user:
        name: "{{ item }}"

      with_items:
        - test1
        - test2
        - test3
        - test4


#.创建tt1 --> bin  tt2 -->root tt3 --->adm   附加组
[root@manager project1]# cat  f20.yml 
- hosts: webservers
  tasks:
    - name: Create User
      user:
        name: "{{ item.name }}"
        groups: "{{ item.groups }}"

      with_items:
        - { name: tt1, groups: bin }
        - { name: tt2, groups: root }
        - { name: tt3, groups: adm }

1.标准循环 --->居多
item
with_items:
- test
2.字典循环: --->居多
itme.name
with_items:
- { name: test }

3.变量循环

• hosts: webservers
  tasks:
  • name: ensure a list of packages installed
    yum: name={{ packages }} state=present
    vars:
    packages:
    - httpd
    - httpd-tools

8.handlers

（1）例题：

[root@manager project1]# cat f22.yml 
- hosts: webservers
  tasks:

    - name: Installed Nginx and PHP Packages
      yum:
        name: nginx
        state: present

    - name: Configure nginx.conf 
      template:
        src: ./file/nginx.conf.j2
        dest: /etc/nginx/nginx.conf
      #监控-->changed状态-->通知-->handlers--->name-->Restart Nginx Server
      notify: Restart Nginx Server
      #notify:
      #  - Restart Nginx Server
      #  - Restart php Server

    - name: Systemd Nginx Server
      systemd:
        name: nginx
        state: started
        enabled: yes

#当nginx或php配置文件发生变更才会触发此操作
  handlers:
    - name: Restart Nginx Server
      systemd:
        name: nginx
        state: restarted

（2）handlers注意事项

    （1）无论多少个task通知了相同的handlers，handlers仅会在所有tasks结束后运行一次。
    （2）只有task发生改变了才会通知handlers，没有改变则不会触发handlers.
    （3）不能使用handlers替代tasks、因为handlers是一个特殊的tasks。