52笔记---变量

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
  vars 关键字
  vars_file 

3.在Inventory主机清单中定义变量
  1）清单文件中直接定义
  2）准备hosts_vars group_vars目录

4.通过外置参数传递（传递）-e
5.变量冲突，优先级
6.变量注册

定义变量

1.（关键字）配置文件内定义变量，但只能是该变量所在的hosts内能调用使用
[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

2.（vars_file）共享，任何 *.yml文件都可以使用

1570755668515.png

[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

在主机清单中定义变量（hosts）

1.清单文件中直接定义  hosts文件定义
[webservers]
172.16.1.7
172.16.1.8 
[webservers:vars]
file_name=hostsfile_group_vars

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

变量冲突，测试优先级

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   单个组  all组
7）通过执行命令传递变量


--->
优先级等级（由高到低）：
外置传入参数-->playbook(vars_files(共享)--->Vars(私有))--->host_Vars -->group_vars/group_name-->group_vars/all

变量注册

register关键字，可以将某个task任务结果存储到变量中，最后使用debug输出变量内容，可用于后续排障
[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      #shell执行的命令赋值于此 

    # echo "$System_Status"
- name: Debug output Variables
    debug:
      msg: "{{ System_Status.stdout_lines }}"  #将赋值的结果输出出来

facts变量

image.png

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，比如：主机名 IP地址 系统版本 CPU数量 内存状态等等
使用场景
  1）检查cpu信息，生成不同的nginx配置文件
        A: 1核心    work_process 1;
        B: 2核心    work_process 2;
  2）检查名称信息，生成不同的zabbix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）检查内存状态，生成不同的memcached的配置文件
  [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=""

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  

#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" )

#安装软件仓库,只有web组的安装webtatic其他的主机全部跳过.
[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*"))

#TASK任务, TASK1任务执行成功,才会执行TASK2  
[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 )

循环语句

#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


#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' }

#创建多个用户（标准型）
[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

handlers

[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

#3.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。


变量->facts-->判断-->循环

* 1.安装Rsyncd服务  (循环)
* 2.安装Redis   (bind  本地IP地址)    facts 
* 3.安装NFS      (配置文件,创建目录,客户端挂载)    变量

(reverse-i-search)`setup': ansible localhost -m setup -i hosts |less