自动化运维工具之Puppet变量、正则表达式、流程控制、类和模板

　　前文我们了解了puppet的file、exec、cron、notify这四种核心资源类型的使用以及资源见定义通知/订阅关系，回顾请参考https://www.cnblogs.com/qiuhom-1874/p/14073437.html；今天我们来了解下puppet中的变量、正则表达式、流程控制、类和模板的相关话题；

　　puppet中的变量

　　在puppet中变量的定义和使用都是要加“$”，比如定义变量$webserver=nginx；则表示把nginx这个字符串复制给$webserver这个变量；引用变量直接使用$webserver即可；在puppet中赋值操作符为“=”,表示把等号右边边的值赋给左边的变量，任何正常数据类型（非正则）的值都可以赋予puppet中的变量，比如字符串、数值、布尔值、数组、hash以及特殊的undef值（即变量未赋值）；

　　puppet中的数据类型

　　　　字符型：非结构化的文本字符串，可以使用引号，也可以不使用引号；单引号表示强引用，双引号表示弱引用；所谓强引用表示变量不会替换，弱引用表示能够进行变量替换；字符型值是支持用转义符；

　　　　数字型：可为整数或浮点数，不过，puppet只有在数值上下文才把数值当作数值型对待，其他情况一律以字符型处理；比如进行加减乘除等运算时，它会把数值型值当作数值进行计算；

　　　　数组：数组值为中括号“[]”中的以逗号分隔的项目列表，最后一个项目后面可以没有逗号；数组中的元素可以为任意可用数据类型，包括hash或其他数组，数组中的元素为数组，我们把这样的数组叫多维数组；数组的索引为从0开始的整数，也可以使用负数索引；

　　　　布尔型：true和false,不能加任何引号；if语句的测试条件和比较表达式都会返回布尔型值，另外，其他数据类型也可以自动转换为布尔型值，如字符串，空串为false,非空则true;数值型就是0为false,非0为true等等；

　　　　undef：从未被声明的变量的值类型即为undef；也可手动为某变量赋予undef值，即直接使用不加引号的undef字符串；有点类似shell中的unset；

　　　　hash：即为外键值数据类型，键和值之间使用“=>”分隔，键值对定义在“{}”中，彼此间以逗号分隔；其键为字符型数据，而值可以为puppet中支持的任意数据类型；访问hash类型的数据元素要使用“键”当作索引进行访问；

　　puppet中变量作用域

　　提示：所谓变量作用域表示变量的使用生效的范围，在puppet中作用域可用于限定变量及资源默认属性的作用范围；但不能用于限定资源名称及资源引用的生效范围；任何给定的scope都可以访问它自己的内容，以及接收来自于其父scope、节点scope以及top scope的内容；简单讲就是作用域小的可以引用作用域大的变量，也可以更改作用域大的变量的值；但是作用域大的不能操作作用域小的变量；如上图所示，top scope仅能访问直接的变量和属性默认值；node scope能访问自己的及top scope的变量和属性默认值；example::parent,example::other和example::four能访问自己的以及节点scope和top scope的变量和默认值；如果要访问非当前scope中的变量，则需要通过完全限制名称进行；如$vhostdir=$apache::params::vhostdir；这里需要注意一点，如果top scope的名称为空，如要引用其变量可以使用类似$::sofamily的方式进行引用；

　　puppet中的内建变量

　　在puppet中变量来源可以从facter，agent，master，解释器以及用户自定义的变量；其中facter是一个工具，它可以收集系统信息，规范化之后存放在一系列变量中，并传递给puppet;facter的各变量是top scope的变量，这意味着，可以在各个manifest中直接通过${fact name}访问所需的fact变量；查看系统fact变量有哪些，可以使用facter -p输出fact变量；agent端的变量常用的有$environment这表示agent端的环境变量，$clientcert表示agent端的证书；$clientversion表示agent puppet的版本信息；master 端常用变量有$servername，该变量表示服务端名称；$serverip服务端ip，$serverversion服务端puppet的版本信息；解释器中的变量$module_name表示正在执行的模块名称；这里需要注意agent和master的内建变量只有在master/agent这种模型中才有效，单机模型无效；

　　puppet中常用的操作符

操作符	描述	操作符	描述	操作符	描述
==	等于	=~	正则模式匹配	+	加
！=	不等于	!~	正则模式不匹配	-	减
<	小于	in	成员关系判定	*	乘
>	大于	and	与	/	除
<=	小于等于	or	或	<<	左移位
>=	大于等于	!	非	>>	右移位

　　puppet中的正则表达式

　　正则表达式在puppet中属于非标准的数据类型，不能赋值给变量，仅能用于有限的几个接受正则表达式的地方使用，即接受使用“=～”或“！～”匹配操作符的位置，通常包含case语句中的selector,以及节点名称匹配的位置；它不能传递给函数或用于资源属性定义；

　　puppet中正则表达式的两个特殊使用方式

　　(?<ENABLED OPTION>:<PATTERN>)和(?-<DISABLED OPTION>:<PATTERN>)，其中OPTIONS有i，m，x，其中i表示忽略字符大小写；m表示把“.”点号当作换行符；x表示忽略<PATTERN>中的空白字符；比如(?imx:PATTENR)就表示忽略字符大小写，把PATTERN中的点号当作换行符，并且忽略其中的空白字符；(?i-mx:PATTERN)表示忽略字符大小写，不把pattern中的点号当换行符，也不忽略pattern中的空白字符；

　　puppet中的流程控制

　　所谓流程控制就是在puppet代码中加入了条件控制语句，如if语句，case语句，selector语句，只有满足了条件才会执行对应的代码；if语句语法如下

　　单分支

if  CONDITION {
    ...
}

　　双分支

if  CONDITION {
    ...
} else {
    ...
}

　　多分支

if  CONDITION {
    ...
} elsif {
    ...
} else{
    ...
}

　　提示：条件可以是变量，比较表达式或有返回值的函数；

　　示例：通过判断不同操作系统来安装apache

[root@node12 ~]# cat if.pp
if $operatingsystem == "CentOS" {
        $webserver = "httpd"
}elsif $operatingsystem == "Ubuntu" {
        $webserver = "apache2"
}else{
        $webserver = "apahce"
}

package{"$webserver":
        ensure  => installed,
}
[root@node12 ~]# 

　　提示：以上资源清单表示，通过判断$operatingsystem这个变量的值来赋值$webserver的值；如果对应$operatingsystem的值为CentOS，则$webserver的值就为httpd,如果是Ubuntu $webserver的值就为apache2，如果前两个条件都不满足，则$webserver的值为apache；然后通过$webserver这个变量的值来安装包；

　　应用资源清单

[root@node12 ~]# puppet apply -v --noop if.pp
Notice: Compiled catalog for node12.test.org in environment production in 0.65 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 '1606994860'
Notice: /Stage[main]/Main/Package[httpd]/ensure: current_value absent, should be present (noop)
Notice: Class[Main]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 1.24 seconds
[root@node12 ~]# puppet apply -v  if.pp      
Notice: Compiled catalog for node12.test.org in environment production in 0.18 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 '1606994891'
Notice: /Stage[main]/Main/Package[httpd]/ensure: created
Notice: Finished catalog run in 7.99 seconds
[root@node12 ~]# 

　　提示：从上述信息中可以看到，当前安装的包上httpd；原因是本机是一个centos系统；$operatingsystem这个变量是一个fact变量，主要保存操作系统名称；

　　示例：if语句中使用正则表达式

[root@node12 ~]# cat if.pp
if $operatingsystem =~/(?i-mx:(centos|redhat))/{
        $webserver = "httpd"
}elsif $operatingsystem =~ /(?i-mx:(ubuntu|debian))/{
        $webserver = "apache2"
}else{
        $webserver = "apahce"
}

package{"$webserver":
        ensure  => installed,
}
[root@node12 ~]# 

　　提示：使用正则表达式需要将正则表达式写在“//”之间；

　　卸载httpd,应用资源清单

[root@node12 ~]# rpm -e httpd
[root@node12 ~]# puppet apply -v  if.pp
Notice: Compiled catalog for node12.test.org in environment production in 0.18 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 '1606995583'
Notice: /Stage[main]/Main/Package[httpd]/ensure: created
Notice: Finished catalog run in 1.86 seconds
[root@node12 ~]# 

　　提示：可以看到应用清单并没有报错，提示httpd已经创建；

　　puppet中的case语句

　　语法

case CONTROL_EXPRESSION {
    case1: { ... }
    case2: { ... }
    case3: { ... }
    ...
    default: { ... }
}

　　提示：case语句和if语句的作用是类似的，case语句会从多个代码块中选择一个分支执行，只要其中任意一个case的值满足对应的控制表达式，就执行对应case后面的代码块，然后退出；如果所有case都不满足，则执行default对应的代码块；这里的控制表达式可以是变量，可以是比较表达式，也可以是有返回值的函数；case可以是字符串，正则表达式，变量，有返回值的函数和default；

　　示例

[root@node12 ~]# cat case.pp
case $osfamily {
        "RedHat":{ $webserver="httpd" }
        /(?i-mx:debian)/:{ $webserver="apache2" }
        default:{ $webserver="apache" }
}

package{"$webserver":
        ensure  => installed,
}
[root@node12 ~]# 

　　卸载httpd，执行资源清单，看看httpd是否会被安装？

[root@node12 ~]# rpm -e httpd
[root@node12 ~]# puppet apply -v  case.pp 
Notice: Compiled catalog for node12.test.org in environment production in 0.18 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 '1606996150'
Notice: /Stage[main]/Main/Package[httpd]/ensure: created
Notice: Finished catalog run in 1.82 seconds
[root@node12 ~]# rpm -q httpd
httpd-2.4.6-97.el7.centos.x86_64
[root@node12 ~]# 

　　提示：可以看到httpd可以正常的安装；

　　selector语句

　　语法

CONTROL_VARIABLE ? {
    case1 => value1,
    case2 => value2,
    ...
    default => valueN,
}

　　提示：整个selector语句会被当作一个单独的值，puppet会将控制变量按列出的次序依次与每个case进行比较，并在遇到一个匹配的case后，将其值作为整个语句的值进行返回，并忽略后面的其他case；控制变量与各case比较的方式和case语句相同，但如果没有任何一个case与控制变量匹配，puppet在编译时将报错，因此，我们在使用selector必须提供一个default case;控制变量只能是一个变量或一个有返回值的函数，不能使用表达式；各个case的值可以是字符串，变量，有返回值的函数，正则表达式或default；

　　示例

[root@node12 ~]# cat selector.pp
$pkgname = $operatingsystem ? {
        /(?i-mx:(ubuntu|debian))/       => 'apache2',
        /(?i-mx:(redhat|fedora|centos))/        => 'httpd',
        default => 'apache',
}
package{"$pkgname":
        ensure  => installed,
}
[root@node12 ~]# 

　　卸载httpd,应用资源清单

[root@node12 ~]# rpm -e httpd
[root@node12 ~]# puppet apply -v --noop selector.pp
Notice: Compiled catalog for node12.test.org in environment production in 0.18 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 '1606997882'
Notice: /Stage[main]/Main/Package[httpd]/ensure: current_value absent, should be present (noop)
Notice: Class[Main]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.08 seconds
[root@node12 ~]# puppet apply -v  selector.pp      
Notice: Compiled catalog for node12.test.org in environment production in 0.18 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 '1606997889'
Notice: /Stage[main]/Main/Package[httpd]/ensure: created
Notice: Finished catalog run in 1.96 seconds
[root@node12 ~]# rpm -q httpd
httpd-2.4.6-97.el7.centos.x86_64
[root@node12 ~]# 

　　提示：可以看到httpd通过使用selector的方式定义的资源清单一样可以正常安装；

　　puppet中的类

　　类是用于同于目标的一组资源，因此，它是命名的代码块，在某一个位置创建之后可在puppet全局使用；puppet中的类和其他编程语言中的类的功能很类似，puppet中的类可被继承，也可以有子类；

　　类的定义语法

class class_name($var1=value1,$var2=value2){
    ... puppet code ...
}

　　提示：class是关键字，class_name是类名，类名只能以小写字母开头，可以包含小写字母，数字，下划线；小括号里是定义类的形参，每个形参可以有默认值，也可以没有，多个形参用逗号隔开；大括号里写puppet的代码；

　　示例：定义一个apache的类

[root@node12 ~]# cat apache.pp
class apache {
        package{"httpd":
                ensure  => installed,
        }
        service{"httpd":
                ensure  => running,
        }
}
[root@node12 ~]# 

　　提示：以上清单中定义了一个apache的类，主要完成了安装包和启动服务；这里需要注意一点，类定义好以后，如果我们不声明类，则它不会执行，有点类似函数一样，要向让类执行，我们需要声明类；

　　在puppet中类的声明常用的方式有两种，第一种是使用include关键字+类名；第二种是类似定义资源一样来声明类，其中资源类型为class，title必须为类名，这种方式通常用于有参数的类的声明；

　　示例：使用include关键字+类名声明类

[root@node12 ~]# cat apache.pp
class apache {
        package{"httpd":
                ensure  => installed,
        }
        service{"httpd":
                ensure  => running,
        }
}

include apache

[root@node12 ~]# 

　　执行清单

[root@node12 ~]# ss -tnl
State      Recv-Q Send-Q         Local Address:Port                        Peer Address:Port              
LISTEN     0      128                        *:26379                                  *:*                  
LISTEN     0      128                        *:22                                     *:*                  
LISTEN     0      100                127.0.0.1:25                                     *:*                  
LISTEN     0      128                        *:27017                                  *:*                  
LISTEN     0      128                       :::22                                    :::*                  
LISTEN     0      100                      ::1:25                                    :::*                  
[root@node12 ~]# puppet apply -v --noop apache.pp 
Notice: Compiled catalog for node12.test.org in environment production in 0.26 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 '1607005266'
Notice: /Stage[main]/Apache/Service[httpd]/ensure: current_value stopped, should be running (noop)
Info: /Stage[main]/Apache/Service[httpd]: Unscheduling refresh on Service[httpd]
Notice: Class[Apache]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.13 seconds
[root@node12 ~]# puppet apply -v  apache.pp       
Notice: Compiled catalog for node12.test.org in environment production in 0.27 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 '1607005272'
Notice: /Stage[main]/Apache/Service[httpd]/ensure: ensure changed 'stopped' to 'running'
Info: /Stage[main]/Apache/Service[httpd]: Unscheduling refresh on Service[httpd]
Notice: Finished catalog run in 0.22 seconds
[root@node12 ~]# ss -tnl
State      Recv-Q Send-Q         Local Address:Port                        Peer Address:Port              
LISTEN     0      128                        *:26379                                  *:*                  
LISTEN     0      128                        *:22                                     *:*                  
LISTEN     0      100                127.0.0.1:25                                     *:*                  
LISTEN     0      128                        *:27017                                  *:*                  
LISTEN     0      128                       :::80                                    :::*                  
LISTEN     0      128                       :::22                                    :::*                  
LISTEN     0      100                      ::1:25                                    :::*                  
[root@node12 ~]# 

　　提示：可以看到httpd服务已经启动；

　　示例：定义带参类

[root@node12 ~]# cat class1.pp
class dbserver ($pkg='mariadb-server',$svr='mariadb'){
        package{"$pkg":
                ensure  => latest,
        }
        service{"$svr":
                ensure  => running,
                enable  => true,
        }
}

if $operatingsystem == "CentOS" or $operatingsystem == "RedHat"{
        case $operatingsystemmajrelease {
                '7': { $pkgname='mariadb-server' $svrname='mariadb' }
                default: { $pkgname='mysql-server' $svrname='mysqld' }
        }
}

class{"dbserver":
        pkg     => $pkgname,
        svr     => $svrname,
}
[root@node12 ~]# 

　　提示：以上清单主要完成对于不同版本的centos，安装和启动不同的服务；在centos7上安装mariadb-server，启动mariadb服务；其他版本的centos安装mysql-server,启动mysqld服务；这里需要注意一点，声明类中的行参不能带$，我们可以理解为行参就是类的一个属性；

　　执行清单

[root@node12 ~]# ss -tnl
State      Recv-Q Send-Q         Local Address:Port                        Peer Address:Port              
LISTEN     0      128                        *:26379                                  *:*                  
LISTEN     0      128                        *:22                                     *:*                  
LISTEN     0      100                127.0.0.1:25                                     *:*                  
LISTEN     0      128                        *:27017                                  *:*                  
LISTEN     0      128                       :::80                                    :::*                  
LISTEN     0      128                       :::22                                    :::*                  
LISTEN     0      100                      ::1:25                                    :::*                  
[root@node12 ~]# puppet apply -v --noop class1.pp 
Notice: Compiled catalog for node12.test.org in environment production in 0.27 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 '1607007562'
Notice: /Stage[main]/Dbserver/Service[mariadb]/ensure: current_value stopped, should be running (noop)
Info: /Stage[main]/Dbserver/Service[mariadb]: Unscheduling refresh on Service[mariadb]
Notice: Class[Dbserver]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.47 seconds
[root@node12 ~]# puppet apply -v  class1.pp       
Notice: Compiled catalog for node12.test.org in environment production in 0.27 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 '1607007569'
Notice: /Stage[main]/Dbserver/Service[mariadb]/ensure: ensure changed 'stopped' to 'running'
Info: /Stage[main]/Dbserver/Service[mariadb]: Unscheduling refresh on Service[mariadb]
Notice: Finished catalog run in 2.76 seconds
[root@node12 ~]# ss -tnl
State      Recv-Q Send-Q         Local Address:Port                        Peer Address:Port              
LISTEN     0      128                        *:26379                                  *:*                  
LISTEN     0      128                        *:22                                     *:*                  
LISTEN     0      100                127.0.0.1:25                                     *:*                  
LISTEN     0      128                        *:27017                                  *:*                  
LISTEN     0      50                         *:3306                                   *:*                  
LISTEN     0      128                       :::80                                    :::*                  
LISTEN     0      128                       :::22                                    :::*                  
LISTEN     0      100                      ::1:25                                    :::*                  
[root@node12 ~]# systemctl is-enabled mariadb.service 
enabled
[root@node12 ~]# 

　　提示：可以看到在当前系统上执行清单，启动了mariadb；

　　类的继承

　　类的继承是子类继承父类中的所有功能代码，它可以对父类中的所有属性进行修改，其定义语法如下

class childer_class_name inherits parent_class_name{
    ...puppet code ...
}

　　提示：子类名称需使用完全限定名称，比如父类是apache，子类名可以写成apache::web;类似这种；inherits是关键字表示继承之意，后面加父类名称；

　　示例

[root@node12 ~]# cat redis.pp
class redis{
        package{"redis":
                ensure  => installed,
        }
        service{"redis":
                ensure  => running,
                enable  => true,
                hasrestart      => true,
                restart => 'service redis restart',
        }
}

class redis::master inherits redis {
        file{"/etc/redis.conf":
                ensure  => file,
                source  => '/root/redis-master.conf',
        }
        Service["redis"]{
                subscribe       => File["/etc/redis.conf"],
                restart => 'systemctl restart redis'
        }
}

include redis::master
[root@node12 ~]# 

　　提示：以上清单定义了两个类，一个是父类名为reids，另一个为子类名为redis::master；子类继承父类，并在其基础上新增了file资源以及增加了service资源的订阅关系；

　　本地redis-master.conf配置文件内容

[root@node12 ~]# cat /root/redis-master.conf 
bind 0.0.0.0
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize no
supervised no
pidfile /var/run/redis_6379.pid
loglevel notice
logfile /var/log/redis/redis.log
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /var/lib/redis
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes
[root@node12 ~]# 

　　执行清单，看看redis是否会监听在本机所有地址的6379端口？

[root@node12 ~]# ss -tnl
State       Recv-Q Send-Q       Local Address:Port                      Peer Address:Port              
LISTEN      0      128                      *:22                                   *:*                  
LISTEN      0      100              127.0.0.1:25                                   *:*                  
LISTEN      0      128                      *:27017                                *:*                  
LISTEN      0      50                       *:3306                                 *:*                  
LISTEN      0      128                     :::80                                  :::*                  
LISTEN      0      128                     :::22                                  :::*                  
LISTEN      0      100                    ::1:25                                  :::*                  
[root@node12 ~]# puppet apply -v --noop redis.pp 
Notice: Compiled catalog for node12.test.org in environment production in 0.32 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 '1607008817'
Notice: /Stage[main]/Redis::Master/File[/etc/redis.conf]/content: current_value {md5}cb9ab7d298a50a0de20077de143e3f73, should be {md5}12e59b058c0ef61ad52bcfa2d4de58ff (noop)
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Scheduling refresh of Service[redis]
Notice: Class[Redis::Master]: Would have triggered 'refresh' from 1 events
Notice: /Stage[main]/Redis/Service[redis]/ensure: current_value stopped, should be running (noop)
Info: /Stage[main]/Redis/Service[redis]: Unscheduling refresh on Service[redis]
Notice: Class[Redis]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 2 events
Notice: Finished catalog run in 0.18 seconds
[root@node12 ~]# puppet apply -v  redis.pp       
Notice: Compiled catalog for node12.test.org in environment production in 0.33 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 '1607008824'
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Filebucketed /etc/redis.conf to puppet with sum cb9ab7d298a50a0de20077de143e3f73
Notice: /Stage[main]/Redis::Master/File[/etc/redis.conf]/content: content changed '{md5}cb9ab7d298a50a0de20077de143e3f73' to '{md5}12e59b058c0ef61ad52bcfa2d4de58ff'
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Scheduling refresh of Service[redis]
Notice: /Stage[main]/Redis/Service[redis]/ensure: ensure changed 'stopped' to 'running'
Info: /Stage[main]/Redis/Service[redis]: Unscheduling refresh on Service[redis]
Notice: Finished catalog run in 0.13 seconds
[root@node12 ~]# ss -tnl
State       Recv-Q Send-Q       Local Address:Port                      Peer Address:Port              
LISTEN      0      128                      *:6379                                 *:*                  
LISTEN      0      128                      *:22                                   *:*                  
LISTEN      0      100              127.0.0.1:25                                   *:*                  
LISTEN      0      128                      *:27017                                *:*                  
LISTEN      0      50                       *:3306                                 *:*                  
LISTEN      0      128                     :::80                                  :::*                  
LISTEN      0      128                     :::22                                  :::*                  
LISTEN      0      100                    ::1:25                                  :::*                  
[root@node12 ~]# 

　　提示：可以看到redis监听在本机任何地址的6379端口；

　　puppet中的模板

　　puppet中的模板和ansible中的模板功能很类似，主要用在为一些服务提供配置文件模板，不同于ansible中的模板，puppet中的模板使用的erb模板语言，ansible使用的是jinja2模板语言；在puppet中使用模板的语法如下

file{'title':
    ensure	=> file,
    content	=> template('/PATH/TO/ERB_FILE'),
}

　　提示：在复制配置文件时，指定源需使用content来指定，并且调用内建函数template来指定要复制的源文件，通常这个源文件就是一个模板配置文件；

　　在模板文件中使用内嵌的变量替换机制，其语法如下

<%= @VARIABLE_NAME %>

　　提示：我们需要把要替换的值用上述变量的方式代替即可；

　　示例：替换redis监听地址

[root@node12 ~]# grep ^bind redis-master.conf.erb
bind <%= @ipaddress %>
[root@node12 ~]# 

　　提示：以上内容表示bind 后面的值为ipaddress这个变量的值；这个变量是fact变量，主要用于存放本机ip地址；

　　定义资源清单

[root@node12 ~]# cat redis.pp
class redis{
        package{"redis":
                ensure  => installed,
        }
        service{"redis":
                ensure  => running,
                enable  => true,
                hasrestart      => true,
                restart => 'service redis restart',
        }
}

class redis::master inherits redis {
        file{"/etc/redis.conf":
                ensure  => file,
                content => template('/root/redis-master.conf.erb'),
        }
        Service["redis"]{
                subscribe       => File["/etc/redis.conf"],
                restart => 'systemctl restart redis'
        }
}

include redis::master
[root@node12 ~]# 

　　提示：以上清单在定义配置文件源文件时，指定content属性为内建函数template调用/root/redis-master.conf.erb；表示使用这个模板文件覆盖/etc/redis.conf文件内容；

　　执行清单，看看对应redis是否监听在本机192.168.0.52这个地址上呢？

[root@node12 ~]# ss -tnl
State       Recv-Q Send-Q       Local Address:Port                      Peer Address:Port              
LISTEN      0      128                      *:6379                                 *:*                  
LISTEN      0      128                      *:22                                   *:*                  
LISTEN      0      100              127.0.0.1:25                                   *:*                  
LISTEN      0      128                      *:27017                                *:*                  
LISTEN      0      50                       *:3306                                 *:*                  
LISTEN      0      128                     :::80                                  :::*                  
LISTEN      0      128                     :::22                                  :::*                  
LISTEN      0      100                    ::1:25                                  :::*                  
[root@node12 ~]# puppet apply -v --noop redis.pp 
Notice: Compiled catalog for node12.test.org in environment production in 0.33 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 '1607010053'
Notice: /Stage[main]/Redis::Master/File[/etc/redis.conf]/content: current_value {md5}12e59b058c0ef61ad52bcfa2d4de58ff, should be {md5}52397ae299aa46fe4103654abd62f5fd (noop)
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Scheduling refresh of Service[redis]
Notice: Class[Redis::Master]: Would have triggered 'refresh' from 1 events
Notice: /Stage[main]/Redis/Service[redis]: Would have triggered 'refresh' from 1 events
Notice: Class[Redis]: Would have triggered 'refresh' from 1 events
Notice: Stage[main]: Would have triggered 'refresh' from 2 events
Notice: Finished catalog run in 0.12 seconds
[root@node12 ~]# puppet apply -v  redis.pp       
Notice: Compiled catalog for node12.test.org in environment production in 0.33 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 '1607010059'
Info: FileBucket got a duplicate file {md5}12e59b058c0ef61ad52bcfa2d4de58ff
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Filebucketed /etc/redis.conf to puppet with sum 12e59b058c0ef61ad52bcfa2d4de58ff
Notice: /Stage[main]/Redis::Master/File[/etc/redis.conf]/content: content changed '{md5}12e59b058c0ef61ad52bcfa2d4de58ff' to '{md5}52397ae299aa46fe4103654abd62f5fd'
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Scheduling refresh of Service[redis]
Notice: /Stage[main]/Redis/Service[redis]: Triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.15 seconds
[root@node12 ~]# ss -tnl
State       Recv-Q Send-Q       Local Address:Port                      Peer Address:Port              
LISTEN      0      128           192.168.0.52:6379                                 *:*                  
LISTEN      0      128                      *:22                                   *:*                  
LISTEN      0      100              127.0.0.1:25                                   *:*                  
LISTEN      0      128                      *:27017                                *:*                  
LISTEN      0      50                       *:3306                                 *:*                  
LISTEN      0      128                     :::80                                  :::*                  
LISTEN      0      128                     :::22                                  :::*                  
LISTEN      0      100                    ::1:25                                  :::*                  
[root@node12 ~]# grep ^bind /etc/redis.conf 
bind 192.168.0.52
[root@node12 ~]# 

　　提示：可以看到对应redis已经监听在192.168.0.52这个地址，并且配置文件中的bing的值也是192.168.0.52；

　　在模板中使用自定义变量

[root@node12 ~]# grep -Ei "^bind|port" redis-master.conf.erb
bind <%= @redis_bindip%>
port <%= @redis_port %>
[root@node12 ~]# 

　　在资源中定义变量

[root@node12 ~]# cat redis.pp
class redis{
        package{"redis":
                ensure  => installed,
        }
        service{"redis":
                ensure  => running,
                enable  => true,
                hasrestart      => true,
                restart => 'service redis restart',
        }
}

class redis::master($redis_bindip='0.0.0.0',$redis_port='6379') inherits redis {
        file{"/etc/redis.conf":
                ensure  => file,
                content => template('/root/redis-master.conf.erb'),
        }
        Service["redis"]{
                subscribe       => File["/etc/redis.conf"],
                restart => 'systemctl restart redis'
        }
}

class{"redis::master":
        redis_port      => '16379',
}
[root@node12 ~]# 

　　提示；在该资源中声明类时，传递了redis_port这个形参的值为16379，默认的redis_bindip为0.0.0.0；

　　执行清单，看看redis是否监听在本机所有地址的16379端口？

[root@node12 ~]# puppet apply -v  redis.pp 
Warning: Config file /etc/puppet/hiera.yaml not found, using Hiera defaults
Notice: Compiled catalog for node12.test.org in environment production in 0.38 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 '1607010599'
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Filebucketed /etc/redis.conf to puppet with sum 52397ae299aa46fe4103654abd62f5fd
Notice: /Stage[main]/Redis::Master/File[/etc/redis.conf]/content: content changed '{md5}52397ae299aa46fe4103654abd62f5fd' to '{md5}13a04cb20de2d787e0e18c1c13560cab'
Info: /Stage[main]/Redis::Master/File[/etc/redis.conf]: Scheduling refresh of Service[redis]
Notice: /Stage[main]/Redis/Service[redis]: Triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.15 seconds
[root@node12 ~]# ss -tnl
State       Recv-Q Send-Q       Local Address:Port                      Peer Address:Port              
LISTEN      0      128                      *:22                                   *:*                  
LISTEN      0      100              127.0.0.1:25                                   *:*                  
LISTEN      0      128                      *:16379                                *:*                  
LISTEN      0      128                      *:27017                                *:*                  
LISTEN      0      50                       *:3306                                 *:*                  
LISTEN      0      128                     :::80                                  :::*                  
LISTEN      0      128                     :::22                                  :::*                  
LISTEN      0      100                    ::1:25                                  :::*                  
[root@node12 ~]# grep -Ei "^bind|port" /etc/redis.conf 
bind 0.0.0.0
port 16379
[root@node12 ~]# 

　　提示：可以看到对应redis监听在本机所有地址的16379端口，并且对应配置文件也发生了相应的变量替换；

　　以上就是puppet的模板中使用变量替换的使用方式，更多erb模板语言的使用，请参考官方文档https://puppet.com/docs/puppet/7.0/lang_template_erb.html#lang_template_erb；

　　到此puppet中的变量、正则表达式、流程控制、类和模板的使用和演示就完了；有了这些基本编程元素的存在，使得puppet的资源清单变得灵活和通用，我们可以写一个资源清单适用几乎所有的不同的系统；