puppet 配置练习

mikechenjs

puppet 配置练习

[iyunv@puppetagent ~]# puppet describe user  //查看配置说明

[iyunv@puppetagent manifests]# cat test1.pp

一、用户与用户组
group:
   name: 组名
   gid : 组号
   ensure: present,absent
   system: true，false 是否是系统组，2000以前为系统组
   members: 组成员
user:
   name: 用户名
   commet: 用户注释
   ensure: present,absent
   expiry: 过期期限
   gid: 基本组
   groups: 附加组
   shell: 默认shell
   system: true,false
   uid: 用户ID
   password: 密码



group {'zabbix':
        gid         => 2001,
        ensure         => present,

}

user {'zabbix01':
        uid        => 2000,
        gid        => 2001,
        shell        => '/bin/bash',
        home         => '/home/zabbix01',
        ensure        => present,
}

[iyunv@puppetagent manifests]# vim test1.pp
[iyunv@puppetagent manifests]# puppet apply -v test1.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.30 seconds
Info: Applying configuration version '1506581582'
Notice: /Stage[main]/Main/Group[zabbix]/ensure: created
Notice: /Stage[main]/Main/User[zabbix01]/ensure: created
Info: Creating state file /var/lib/puppet/state/state.yaml
Notice: Finished catalog run in 0.10 seconds

root@puppetagent manifests]# tail -1 /etc/passwd
zabbix01:x:2000:2001::/home/zabbix01:/bin/bash

错误提示： 一般是前一行后面的，号没写
[iyunv@puppetagent manifests]# puppet apply -v test1.pp
Error: Could not parse for environment production: Syntax error at 'uid'; expected '}' at /home/manifests/test1.pp:9 on node puppetagent.gbnc.com
Error: Could not parse for environment production: Syntax error at 'uid'; expected '}' at /home/manifests/test1.pp:9 on node puppetagent.gbnc.com

二、文件file
  content: 直接给出文件内容
  source: 从指定位置下载文件
  ensure: file,link,directory,present,absent
  force: 强制创建，会覆盖原有的yes,no,true,flase
  group: 属组
  owner: 属主
  mode: 权限，支持多种格式，八进制，u,g,o
  path: 目标路径
  source: 源文件路径，可以是本地文件路径，也可以使用puppet:///
  target: 当ensure为link时，target表示path指向的文件是一个符号链接文件，
  checksum：文件校验md5,md5lite,sha256,none  
   
[iyunv@puppetagent manifests]# cat test2.pp
file{'/tmp/mydir':
        ensure         => directory,

}

file {'/tmp/mydir/myfile':
        content        => 'this is a test file\n great!!',
        ensure        => file,
        owner        => 'zabbix01',
        group        => 'zabbix',
        mode        => 0400,

}

file {'/tmp/fstab.test':
        source        => '/etc/fstab',
        ensure        => file,
  
}

file {'/tmp/file.link':
        ensure        => link,
        target        => '/tmp/fstab.test',
}

[iyunv@puppetagent manifests]# puppet apply -v test2.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.15 seconds
Info: Applying configuration version '1506588419'
Notice: /Stage[main]/Main/File[/tmp/fstab.test]/ensure: defined content as '{md5}fdbfec63861f05f36b4a1b5d8c7ab1ec'
Notice: /Stage[main]/Main/File[/tmp/file.link]/ensure: created
Notice: /Stage[main]/Main/File[/tmp/mydir]/ensure: created
Notice: /Stage[main]/Main/File[/tmp/mydir/myfile]/ensure: defined content as '{md5}435a3c2e09594ba689cc94f51691ca5b'
Notice: Finished catalog run in 0.08 seconds

[iyunv@puppetagent tmp]# ls -l
总用量 4
lrwxrwxrwx. 1 root root  15 9月  28 16:47 file.link -> /tmp/fstab.test
-rw-r--r--. 1 root root 465 9月  28 16:47 fstab.test
drwxr-xr-x. 2 root root  20 9月  28 16:47 mydir

[iyunv@puppetagent tmp]# ls -l mydir/myfile
-r--------. 1 zabbix01 zabbix 29 9月  28 16:47 mydir/myfile

三、exec 运行命令，命令应该有“幂等性”
    幂等性，运行多次命令，结果没有损害性
    实现：1、命令本身有
          2、资源有onlyif,unless等属性来实现
          3、资源有refreshonly属性，以实现只有订阅的资源发生变化时才执行

    command: 运行的命令
    creates: 指定的文件不存在时才运行命令
    cwd: cd 到指定目录运行命令
    environment: 指定环境变量
    user: 指定用户身份运行
    group:指定组身份运行
    onlyif: 给定一个测试命令运行成功了，返回时为0时，才会运行命令
    exec { "logrotate":
            path   => "/usr/bin:/usr/sbin:/bin",
            onlyif => "test `du /var/log/messages | cut -f1` -gt 100000"  //成功才运行logrotate
          }
    unless: 与onlyif相反
     exec { "/bin/echo root >> /usr/lib/cron/cron.allow":
          path   => "/usr/bin:/usr/sbin:/bin",
          unless => "grep root /usr/lib/cron/cron.allow 2>/dev/null"  //没有root时加
        }
   refresh: 接收其它资源发来的通知时，默认是重新运行exec的命令，有refresh时运行其指定的命令
   refreshonly : 仅在收到refresh通知时，执行此资源
   returns: 期望的状态返回值，返回非此值进表示命令执行失败
   tries: 尝试执行的次数
   timeout: 超时时长
   path: 指定PATH环境变量，可指多个用["/usr/bin", "/usr/sbin"],
Notice: Finished catalog run in 0.05 seconds

[iyunv@puppetagent manifests]# cat test3.pp
exec {'/usr/sbin/modprobe xfs':
        user        => 'root',
        group        => 'root',
        refresh        => '/usr/sbin/modprobe -r xfs && /usr/sbin/modprobe xfs',
        timeout        => 5,
        tries        => 2,
}

[iyunv@puppetagent manifests]# puppet apply -v test3.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.06 seconds
Info: Applying configuration version '1506644123'
Notice: /Stage[main]/Main/Exec[/usr/sbin/modprobe xfs]/returns: executed successfully
Notice: Finished catalog run in 0.05 seconds

错误提示： 命令要用绝对路径，或用path指定目录
   [iyunv@puppetagent manifests]# puppet apply -v test3.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.05 seconds
Error: Parameter refresh failed on Exec[modprobe xfs]: 'modprobe -r xfs && modprobe xfs' is not qualified and no path was specified. Please qualify the command or specify a path. at /home/manifests/test3.pp:7
Wrapped exception:
'modprobe -r xfs && modprobe xfs' is not qualified and no path was specified. Please qualify the command or specify a path.

[iyunv@puppetagent manifests]# cat test4.pp
exec {'echo hello > /tmp/hello.file':
        user        => root,
        group        => root,
        path        => '/usr/bin',
        creates        => '/tmp/hello.file'        //存在不执行，不存在执行
}

[iyunv@puppetagent manifests]# puppet apply -v test4.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.05 seconds
Info: Applying configuration version '1506644568'
Notice: Finished catalog run in 0.04 seconds
[iyunv@puppetagent manifests]# rm -rf /tmp/hello.file  //删掉后，执行
[iyunv@puppetagent manifests]# puppet apply -v test4.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.06 seconds
Info: Applying configuration version '1506644586'
Notice: /Stage[main]/Main/Exec[echo hello > /tmp/hello.file]/returns: executed successfully
Notice: Finished catalog run in 0.06 seconds
[iyunv@puppetagent manifests]# cat /tmp/hello.file
hello

[iyunv@puppetagent manifests]# cat test5.pp
exec {'echo hello > /tmp/hello01.file':
        user        => root,
        group        => root,
        path        => '/usr/bin',
        unless        => 'test -e /tmp/hello01.file'        //指定命令返回值不为真，就执行
}

[iyunv@puppetagent manifests]# ls /tmp/hello01.file
/tmp/hello01.file
[iyunv@puppetagent manifests]# puppet apply -v test5.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.06 seconds
Info: Applying configuration version '1506644862'
Notice: Finished catalog run in 0.05 seconds
[iyunv@puppetagent manifests]# rm -rf /tmp/hello01.file
[iyunv@puppetagent manifests]# puppet apply -v test5.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.05 seconds
Info: Applying configuration version '1506644878'
Notice: /Stage[main]/Main/Exec[echo hello > /tmp/hello01.file]/returns: executed successfully
Notice: Finished catalog run in 0.06 seconds
[iyunv@puppetagent manifests]# cat /tmp/hello01.file
hello

四、cron 任务计划
    ensure: present, absent
    command: 要运行的命令，要用绝对路径，在此不能用path指定
    hour:
    minute:
    month:
    monthday:
    weekday:
    name:
    user: 运行的用户
    environment: 运行时的环境变量

[iyunv@puppetagent manifests]# cat test6.pp
cron{'sync time':
        command => 'ntpdate 172.16.0.1 &> /dev/null',
        minute        => '*/10',
        ensure        => 'present',
}

[iyunv@puppetagent manifests]# crontab -l
# Puppet Name: sync time
*/10 * * * * ntpdate 172.16.0.1 &> /dev/null

五、package 程序包管理
   ensure: installed,latest,VERSION(2.3.1-2.el7),present,absent
   name: 包名
   source: 包来源
   provider: rpm

[iyunv@puppetagent manifests]# cat test7.pp
package{'zsh':
        ensure => latest,

}

package{'jdk':
        ensure        => installed,
        source        => '/root/jdk-8u144-linux-x64.rpm',
          provider => 'rpm',
}

[iyunv@puppetagent manifests]# puppet apply -v test7.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.58 seconds
Warning: The package type's allow_virtual parameter will be changing its default value from false to true in a future release. If you do not want to allow virtual packages, please explicitly set allow_virtual to false.  //可以在服务器端的 pp文件中的package 中加入 ：allow_virtual => false,  来解决出现的警告。
   (at /usr/share/ruby/vendor_ruby/puppet/type.rb:816:in `set_default')
Info: Applying configuration version '1506649918'
Notice: /Stage[main]/Main/Package[zsh]/ensure: created
Notice: /Stage[main]/Main/Package[jdk]/ensure: created
Notice: Finished catalog run in 22.50 seconds

[iyunv@puppetagent manifests]# java -version
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
[iyunv@puppetagent manifests]# which zsh
/usr/bin/zsh

六、service 管理服务
    enable: 是否开机启动，true, false
    ensure: running, stopped
    hasrestart: 是否支持restart参数
    hasstatus: 是否支持status参数
    name:
    path:
    pattern: 当脚本不支持restart/status时，用于确定服务是否处于运行状态
    restart: 指定用于服务“重启”的命令
    start:
    stop:
    status:

[iyunv@puppetagent manifests]# cat test8.pp
package{'nginx':
        ensure        =>latest,
}

service{'nginx':
        ensure        => running,
        enable        => true,
        hasrestart => true,
        hasstatus  => true,
        restart        => 'systemctl reload nginx.service',
        
       
}

[iyunv@puppetagent manifests]# puppet apply -v test8.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.73 seconds
Warning: The package type's allow_virtual parameter will be changing its default value from false to true in a future release. If you do not want to allow virtual packages, please explicitly set allow_virtual to false.  
   (at /usr/share/ruby/vendor_ruby/puppet/type.rb:816:in `set_default')
Info: Applying configuration version '1506651656'
Notice: /Stage[main]/Main/Package[nginx]/ensure: created
Notice: /Stage[main]/Main/Service[nginx]/ensure: ensure changed 'stopped' to 'running'
Info: /Stage[main]/Main/Service[nginx]: Unscheduling refresh on Service[nginx]
Notice: Finished catalog run in 15.99 seconds

if value = parameter.default and ! value.nil?

[iyunv@puppetagent manifests]# rpm -q nginx
nginx-1.10.2-1.el7.x86_64

[iyunv@puppetagent manifests]# netstat -lupnt |grep nginx
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      13283/nginx: master
tcp6       0      0 :::80                   :::*                    LISTEN      13283/nginx: master


七、Metaparameters
    资源引用  
    Type [title''] ，第一个字母要大写
    依赖关系:
        被依赖关系中使用：before
        依赖其它资源的资源：require
        链式依赖： ->
[iyunv@puppetagent manifests]# cat test9.pp

group {'zabbix':
        gid         => 2001,
        ensure         => present,
        before        => User['zabbix02'],   //被User['zabbix02']依赖
}

user {'zabbix02':
        uid        => 2001,
        gid        => 2001,
        shell        => '/bin/bash',
        home         => '/home/zabbix02',
        ensure        => present,
}

user {'zabbix03':
        uid     => 2002,
        gid     => 2001,
        shell   => '/bin/bash',
        home    => '/home/zabbix03',
        ensure  => present,
        require => Group['zabbix'],  //依赖于 Group['zabbix']
} ->   //后面file依赖于此资源

file{'/tmp/zabbix03.file':
        content        => 'this is a zabbix03',
        ensure        => present,

}

    通知关系
            notify: 被依赖关系中使用
        subcrible: 监听其它资源的资源
        ～>: 链式通知


[iyunv@puppetagent manifests]# cat test10.pp
package{'nginx':
        ensure        =>latest,
}

file{'/etc/nginx/nginx.conf':
        ensure        =>file,
        source        =>'/root/modules/nginx/conf/nginx.conf',
        require        => Package['nginx'],
        notify        => Service['nginx'],  //此资源有改变进，通知Service['nginx']
}

service{'nginx':
        ensure        => running,
        enable        => true,
        hasrestart => true,
        hasstatus  => true,
       # restart        => 'systemctl reload nginx.service',
        require        => [Package['nginx'],File['/etc/nginx/nginx.conf']],
       
}


[iyunv@puppetagent manifests]# netstat -ltupn |grep nginx
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      17576/nginx: master
[iyunv@puppetagent manifests]# vim /root/modules/nginx/conf/nginx.conf
[iyunv@puppetagent manifests]# cat /root/modules/nginx/conf/nginx.conf |grep listen
        listen       80 default_server;   //更改

[iyunv@puppetagent manifests]# puppet apply -v test10.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.82 seconds
Warning: The package type's allow_virtual parameter will be changing its default value from false to true in a future release. If you do not want to allow virtual packages, please explicitly set allow_virtual to false.
   (at /usr/share/ruby/vendor_ruby/puppet/type.rb:816:in `set_default')
Info: Applying configuration version '1506656725'
Info: /Stage[main]/Main/File[/etc/nginx/nginx.conf]: Filebucketed /etc/nginx/nginx.conf to puppet with sum 73972f6c9f693b7b2bf4f5872df65a28
Notice: /Stage[main]/Main/File[/etc/nginx/nginx.conf]/content: content changed '{md5}73972f6c9f693b7b2bf4f5872df65a28' to '{md5}40fed2ca309c9d452fbc4d9840ff22c7'
Info: /Stage[main]/Main/File[/etc/nginx/nginx.conf]: Scheduling refresh of Service[nginx]  //有改变文件，所以refresh
Notice: /Stage[main]/Main/Service[nginx]: Triggered 'refresh' from 1 events
Notice: Finished catalog run in 4.61 seconds
[iyunv@puppetagent manifests]# netstat -ltupn |grep nginx
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      17808/nginx: master


八、变量
    变量名都以$开头，赋值符号为=，任何非正则表达式类型的数据都可以赋值给变量
    作用域：
         TOP Scope 所有节点有效
         Node Scope 节点内有效
         class 类内有效，子类内有效，子类可继承父类
    变量的引用路径：
        相对路径
        绝对路径：
            $::scope::scope::variable
    变量的赋值符号：
        =
        += 追加
    数据类型：
        布尔型： true,false
        undef:  未指定
        字符型： 可以不用引号，单引号（强引用），双引号（弱引用）
        数值型 ：整数和浮点数
        数组：[item1,item2,....]
        hash: {key => vlaue, key => value,....} 键key为字符串，value为任何类型
        
      正则表达式：
          非标准数据类型，不能赋值给变量
                语法结构：
                    （?<ENABLED OPTION>:<SUBPATTERN>）
                        （?-<DISABLED OPTION>:<SUBPATTERN>）

                OPTION:
                        i: 忽略字符大小写
                        m: 把.当换行符
                        x: 忽略空白和注释
        表达式：
            比较操作符：==，!=,<,<=,>,>=,!～,=～,in
            逻辑操作符：and,or,!
            算术操作符：+，-,*,/,%,>>,<<
            
        变量的种类：
            自定义变量
            facter变量 ：用facter -p命令可获得
            内置变量：
                客户端内置：
                        $clientcert
                        $clientversion
                   服务器内置：
                        $servername
                        $serverip
                        $serverversion
                        #modules_name
九、条件判断：
        if,case,selector,unless
        if 语句：
                if CONDITION {
                        .......
                }
                elseif CONDITION {
                       .......
                }
                       else {  
                .........
                }
       CONDITION的用法：
                1、比较表达式
                2、变量引用
                3、有返回值的函数调用


[iyunv@puppetagent manifests]# cat test11.pp
if $operatingsystem == "Centos" {
        notice("the host OS is a $operatingsystem linux")
}
else {
        notice(" the host os isn't a $operatingsystem linux")
}

[iyunv@puppetagent manifests]# puppet apply -v test11.pp
Notice: Scope(Class[main]): the host OS is a CentOS linux  //结果
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.02 seconds
Info: Applying configuration version '1506734001'
Notice: Finished catalog run in 0.04 seconds

if $operatingsystem =~ /^(?i-mx:(Centos|Redhat))/ {
        notice("the host OS is a $1 linux")   //$1为后向引用
}
else {
        notice(" the host os isn't a $operatingsystem linux")
}

[iyunv@puppetagent manifests]# puppet apply -v test11.pp
Notice: Scope(Class[main]): the host OS is a CentOS linux
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.02 seconds
Info: Applying configuration version '1506734525'
Notice: Finished catalog run in 0.04 seconds

            CASE语句
                case CONTROL_EXPESS {
                        case1,.....:{statement....}
                        case2,.....:{statement....}
                        default:    {statement....}
                        }

        CONTROL_EXPESS: 表达式、变量，有返回值的函数
        case: 字符串、变量、正则表达式、有返回值的函数、default

[iyunv@puppetagent manifests]# cat test12.pp
case $operatingsystem {
        'Ubuntu':        {notice("Welcome to Ubuntu system !!!")}
        'Freebsd','Solaris':        {notice("Welcome to UNIX OSFmamily!!! ")}
        /^(?i-mx:(Centos|Redhat))$/:        {notice("Welcome to $1 linux !!!")}
        default:        {notice("Welcome linux !!!")}
}

[iyunv@puppetagent manifests]# puppet apply -v test12.pp
Notice: Scope(Class[main]): Welcome to CentOS linux !!!
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.02 seconds
Info: Applying configuration version '1508977604'
Notice: Finished catalog run in 0.04 seconds

[iyunv@puppetagent manifests]# facter -p |grep "operatingsystem\>"
operatingsystem => CentOS


        Selector语句:
        类似case,但分支的作用是返回一个直接值
        CONTROL_VARIABLE ? {
                case => value1
                case => value2
                default => valueN
                }

        CONTROL_VARIABLE：变量，有返回值的函数，不能用是表达式
        case: 直接值（带引号），变量，有返回值的函数，正则表达式，default
               

[iyunv@puppetagent manifests]# cat test13.pp
$webserver = $operatingsystem ? {
        /(?i-mx:ubuntu|debian)/        => 'apache2',
        /(?i-mx:centos|fedora|redhat)/        => 'httpd',
}

exec {"/bin/echo $webserver >> /tmp/echo.file":
}

[iyunv@puppetagent manifests]# puppet apply -v test13.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.07 seconds
Info: Applying configuration version '1506736956'
Notice: /Stage[main]/Main/Exec[/bin/echo httpd >> /tmp/echo.file]/returns: executed successfully
Notice: Finished catalog run in 0.09 seconds
[iyunv@puppetagent manifests]# cat /tmp/echo.file
httpd  //结果


十、类class
        用于公共目的的一组资源，是命名的代码块：创建后可在puppet全局进行调用，类可以被继承
        语法格式：
        class class_name {
        ....puppet code....
        }
        备注：类只能包含小写字母、数字、下划线，且必须以小写字母开夈
        类声明（调用）方式1：
                include class_name,class_name,....


[iyunv@puppetagent manifests]# cat test15.pp
class nginx {
$webserver=nginx

package{$webserver:
        ensure        =>latest,
}

file{'/etc/nginx/nginx.conf':
        ensure        =>file,
        source        =>'/root/modules/nginx/conf/nginx.conf',
        require        => Package['nginx'],
        notify        => Service['nginx'],
}

service{$webserver:
        ensure        => running,
        enable        => true,
        hasrestart => true,
        hasstatus  => true,
       # restart        => 'systemctl reload nginx.service',
        require        => [Package['nginx'],File['/etc/nginx/nginx.conf']],
       
}
}
include nginx  //引用类

[iyunv@puppetagent manifests]# puppet apply -v test15.pp
Notice: Compiled catalog for puppetagent.gbnc.com in environment production in 0.80 seconds
Warning: The package type's allow_virtual parameter will be changing its default value from false to true in a future release. If you do not want to allow virtual packages, please explicitly set allow_virtual to false.
   (at /usr/share/ruby/vendor_ruby/puppet/type.rb:816:in `set_default')
Info: Applying configuration version '1506740226'
Notice: /Stage[main]/Nginx/Package[nginx]/ensure: created
Info: FileBucket got a duplicate file {md5}93bc8e01bfd45e7e18b23acc178ae25b
Info: /Stage[main]/Nginx/File[/etc/nginx/nginx.conf]: Filebucketed /etc/nginx/nginx.conf to puppet with sum 93bc8e01bfd45e7e18b23acc178ae25b
Notice: /Stage[main]/Nginx/File[/etc/nginx/nginx.conf]/content: content changed '{md5}93bc8e01bfd45e7e18b23acc178ae25b' to '{md5}40fed2ca309c9d452fbc4d9840ff22c7'
Info: /Stage[main]/Nginx/File[/etc/nginx/nginx.conf]: Scheduling refresh of Service[nginx]
Notice: /Stage[main]/Nginx/Service[nginx]/ensure: ensure changed 'stopped' to 'running'
Info: /Stage[main]/Nginx/Service[nginx]: Unscheduling refresh on Service[nginx]

       
        定义能接受能数的类：
                class class_name($arg1='value1',$arg2='value2'){
                .....puppet code......
                }
                有带参数时会替代value,没有带直接用默认value1
        类声明（调用）方式1：
                class{'class_name':
                arg1 => value1,
                arg2 => value2,
                        }

[iyunv@puppetagent manifests]# cat test15.pp
class nginx ($webserver){
#class nginx ($webserver='nginx') {  //可指定默认值，调用类参数时会覆盖

package{$webserver:
        ensure        =>latest,
}

file{'/etc/nginx/nginx.conf':
        ensure        =>file,
        source        =>'/root/modules/nginx/conf/nginx.conf',
        require        => Package['nginx'],
        notify        => Service['nginx'],
}

service{$webserver:
        ensure        => running,
        enable        => true,
        hasrestart => true,
        hasstatus  => true,
       # restart        => 'systemctl reload nginx.service',
        require        => [Package['nginx'],File['/etc/nginx/nginx.conf']],
       
}
}

class {'nginx':
        webserver => 'nginx',
}

        类继承：
                定义方式：
                        class base_class {
                        .... puppet code.....
                        }
                        class base_class::class_name inherits base_class {
                        .....puppet code.....
                        }
                作用：继承一个已有的类，并实现覆盖资源属性，或赂资源属性追加额外值：
                        =>,+>
                类继承时：
                        （1）声明子类的时，其基类会被首先声明
                        （2）基类成为子类的父作用域，基类中的变量和属性默认值会被子类复制一份
                        （3）子类可以覆盖父类中同一资源的相同属性的值