Puppet运维实战

Puppet基础篇7-编写第一个完整测试模块puppet

工欲善其事必先利其器

将Puppet部署到生产中第一个要编写的模块就是puppet本身，虽然puppet可以运行其它所有模块完成各自的部署，但是puppet一旦出问题，那么一切都会停止工作。当然除了puppet自身模块外，还需要保证网络的通畅以及其它你附加的环境等等。

之前编写过简单的motd模块，大致了解了一些模块的结构以及简单的pp语法，接下来我们进行详细的讲解。那么编写一个完整的puppet模块应该考虑哪些因素呢？

puppet及附属依赖包是否已经安装OK？
puppet配置文件是否正确？
puppet服务是否正常运行？
在更新puppet配置文件的情况下，是否能够主动让puppet服务重启或者reload？
puppet安装包是否能够自动升级到指定版本？

接下来以agent1和agent3为例进行讲解

1、创建puppet模块目录结构

[root@puppetmaster ~]# cd /etc/puppet/modules/
[root@puppetmaster modules]# mkdir puppet
[root@puppetmaster modules]# cd puppet/
[root@puppetmaster puppet]# mkdir files manifests templates #创建模块目录结构
[root@puppetmaster puppet]# tree ../puppet
../puppet
├── files  #存放下载的文件
├── manifests  #存放puppet配置
└── templates  #存放配置模板，方便pp文件引用

3 directories, 0 files
[root@puppetmaster puppet]#

2、创建puppet配置文件

[root@puppetmaster puppet]# cd manifests/
[root@puppetmaster manifests]# touch init.pp config.pp install.pp service.pp params.pp
[root@puppetmaster manifests]# tree ../
../
├── files
├── manifests
│   ├── config.pp  #管理puppet配置
│   ├── init.pp    #管理模块所有pp文件配置
│   ├── install.pp #管理puppet安装
│   ├── params.pp  #管理模块中变量以及一些判断
│   └── service.pp #管理puppet服务
└── templates

3 directories, 5 files

3、编写puppet模块配置文件

整个过程应该是这样，首先应该安装puppet（install.pp），然后配置puppet（config.pp），最后启动puppet服务（service.pp）

注意： 接下来的过程不是一步到位的，是一个循序渐进的过程，一步步指导直到完成一个比较完整的模块。

3.1、编写安装配置文件install.pp

通过package资源实现，更多有关package的语法及案例请访问http://kisspuppet.com/2013/11/11/package/

需要注意的是：class名称要和创建的模块名保持一致，名称为puppet，由于在整个配置文件中init.pp为起始配置文件，包含的都应该是子配置文件，所有应该写成“class主类名称::class子类名称”，而class子类名称需要和创建的pp文件名保持一致，比如puppet::install，那么创建的子类名称就应该是install.pp

3.1.1、编写不具备判断条件的配置文件

节点安装puppet主要还依赖于facter

[root@puppetmaster manifests]# vim install.pp 
class puppet::install{  #一个类包含两个子类
  include puppet::puppet_install,puppet::facter_install
}
class puppet::puppet_install{
  package { 'puppet':
    ensure => installed,  #要求处于被安装状态
  }
}
class puppet::facter_install{
  package { 'facter':
    ensure => installed,
  }
}

也可以用以下两种写法

[root@puppetmaster manifests]# vim install.pp 
class puppet::install{  #一个类包含两个资源
  package { 'puppet':
    ensure => installed,
  }
  package { 'facter':
    ensure => installed,
  }
}

[root@puppetmaster manifests]# vim install.pp 
class puppet::install{
  package { ['puppet','facter']:  #采用数组的形式
    ensure => installed,
  }
}

3.1.2、编写具备判断系统版本条件的模块

存在这样一种情况，在我的yum源中有很多puppet版本，而我只希望所有节点只安装我指定的版本，比如2.7.25，那么如何设置呢？其次，还应该考虑一种情况，节点的系统版本可能会不一样，比如有RHEL5、RHEL6等，那么如何让puppet模块自己去判断呢？

通过以下facter进行判断

[root@agent1 ~]# facter | grep operatingsystemmajrelease
operatingsystemmajrelease => 5
[root@agent3 ~]# facter | grep operatingsystemmajrelease
operatingsystemmajrelease => 6

应该是以下写法比较合理

[root@puppetmaster manifests]# vim install.pp 
class puppet::install{
  include puppet::puppet_install,puppet::facter_install
}
class puppet::puppet_install{
  package { 'puppet':
    ensure => $operatingsystemmajrelease ?{ #判断系统版本
      5 => '2.7.25-1.el5',
      6 => '2.7.25-1.el6',
    }
  }
}
class puppet::facter_install{
  package { 'facter':
    ensure => $operatingsystemmajrelease ?{
      5 => '1.7.5-1.el5',
      6 => '1.7.5-1.el6',
    }
  }
}

3.1.3 添加子类到init.pp中

[root@puppetmaster manifests]# vim init.pp 
class puppet{
  include puppet::install
}

3.1.4 应用到puppet主配置文件site.pp中的节点上

[root@puppetmaster ~]# vim /etc/puppet/manifests/site.pp 

$puppetmaster = 'puppetmaster.kisspuppet.com'

node 'puppetmaster_cert.kisspuppet.com'{
  include  motd,puppet
}
node 'agent1_cert.kisspuppet.com'{
  include  motd,puppet
}

node 'agent2_cert.kisspuppet.com'{
  include  motd,puppet
}

node 'agent3_cert.kisspuppet.com'{
  include  motd,puppet
}

也可以是以下写法

[root@puppetmaster ~]# vim /etc/puppet/manifests/site.pp 
$puppetmaster = 'puppetmaster.kisspuppet.com'

class environments{
  include motd,puppet
}

node 'puppetmaster_cert.kisspuppet.com'{
  include  environments
}
node 'agent1_cert.kisspuppet.com'{
  include  environments
}

node 'agent2_cert.kisspuppet.com'{
  include  environments
}

node 'agent3_cert.kisspuppet.com'{
  include  environments
}

如何所有节点都使用相同的模块，也可以是以下写法

[root@puppetmaster ~]# vim /etc/puppet/manifests/site.pp 

$puppetmaster = 'puppetmaster.kisspuppet.com'

class environments{
  include motd,puppet
}

node default{
   include environments
}

3.1.5、进行简单的测试

降低facter版本为1.7.3

[root@agent1 ~]# rpm -e facter --nodeps
[root@agent1 ~]# rpm -ivh facter-1.7.3-1.el5.x86_64.rpm 
warning: facter-1.7.3-1.el5.x86_64.rpm: Header V3 RSA/SHA1 signature: NOKEY, key ID 4bd6ec30
Preparing...                ########################################### [100%]
   1:facter                 ########################################### [100%]
[root@agent1 ~]# facter --version
1.7.3

通过--noop进行尝试性测试，可以看到节点变化情况，但是不进行更改，这也是puppet强大的地方之一

[root@agent1 ~]# puppet agent -t --noop
info: Caching catalog for agent1_cert.kisspuppet.com
info: Applying configuration version '1394794815'
notice: /Stage[main]/Puppet::Facter_install/Package[facter]/ensure: current_value 1.7.3-1.el5, should be 1.7.5-1.el5 (noop)
notice: Class[Puppet::Facter_install]: Would have triggered 'refresh' from 1 events
notice: Stage[main]: Would have triggered 'refresh' from 1 events
notice: Finished catalog run in 0.23 seconds
[root@agent1 ~]# facter --version
1.7.3

强制执行，可以看到管理端的facter版本变成了puppet模块中指定的版本1.7.5，这其实也说明了rpm包升级的方法！

[root@agent1 ~]# puppet agent -t 
info: Caching catalog for agent1_cert.kisspuppet.com
info: Applying configuration version '1394794815'
notice: /Stage[main]/Puppet::Facter_install/Package[facter]/ensure: ensure changed '1.7.3-1.el5' to '1.7.5-1.el5'
notice: Finished catalog run in 6.27 seconds
[root@agent1 ~]# facter --version
1.7.5

整个过程是这样，节点同步puppetmaster端后发现facter版本号不对，根据系统类型马上调用底层的安装工具yum（其它系统如suse会调用zypper等）进行安装，整个过程是透明的，而这正是puppet所呈现的强大功能之二。

3.2、编写配置文件config.pp

通过file资源实现，更多有关file资源的配置及案例请访问http://kisspuppet.com/2013/11/14/file/

3.2.1、我们暂时只配置puppet.conf文件

[root@puppetmaster manifests]# vim config.pp 
class puppet::config{
  file { '/etc/puppet/puppet.conf':  #节点文件存放的路径
    ensure  => present,  #要求存在
    content => template('puppet/puppet.conf.erb'),  #要求根据模板生成,路径写法为相对路径（templates目录隐藏掉）
    owner   => 'root',  #要求文件属主为root
    group   => 'root',  #要求文件属组为root
    mode    => '0644',  #要求文件权限为644
    require => Class['puppet::install'],  #要求这个文件在配置之前先正确运行install.pp文件，也就是说要求puppet的包应当处于安装状态
  }
}

3.2.2、编写puppet.conf.erb模板

puppet的erb模板的存在是为了解决每个节点单独配置一个文件的问题，因为erb模板可以引用fact变量，变量的内容会根据节点系统的不同而变化。

以下为其中一个节点目前的puppet.conf配置文件，我们先找出会变化的内容

[root@agent1 ~]# vim /etc/puppet/puppet.conf
[main]
    logdir = /var/log/puppet
    rundir = /var/run/puppet
    ssldir = $vardir/ssl

[agent]
    classfile = $vardir/classes.txt
    localconfig = $vardir/localconfig
    server = puppetmaster.kisspuppet.com   #变量
    certname = agent1_cert.kisspuppet.com  #变量
    runinterval = 10

接下来解决这两个变量

之前我们说过创建params.pp就是为了解决变量问题，我们先用这个解决

找出fact值具有唯一性的fact，比如hostname

[root@agent1 ~]# facter |grep hostname
hostname => agent1

[root@agent3 ~]# facter |grep hostname
hostname => agent3

编写params.pp文件，增加certname变量

[root@puppetmaster manifests]# vim params.pp 
class puppet::params {
  $puppetserver = 'puppetmaster.kisspuppet.com'  #增加puppetserver变量指向puppetmaster名称
  case $hostname{   #增加certname变量
    agent1: {
      $certname = 'agent1_cert.kisspuppet.com'  
    }
    agent3: {
      $certname = 'agent3_cert.kisspuppet.com'
    }
    default: {  #设置默认不存在的情况下报错
      fail("certname is not supported on ${::operatingsystem}")
    }
  }
}

注意：这种创建变量的方法在大量节点的情况下显然不是最好的方法，能否通过fact变量实现呢，答案是可以的，可写成以下方式

[root@puppetmaster manifests]# vim params.pp 
class puppet::params {
  $puppetserver = 'puppetmaster.kisspuppet.com'
  $certname = "${::hostname}_cert.kisspuppet.com"  #通过fact：hostname实现
  case $operatingsystemmajrelease{
    5: {
      $puppet_release = '2.7.23-1.el5'
      $facter_release = '1.7.3-1.el5'
    }
    6: {
      $puppet_release = '2.7.23-1.el6'
      $facter_release = '1.7.3-1.el6'
    }
    default: {
      fail("Module puppet is not supported on ${::operatingsystem}")
    }
  }
}

备注：这里使用的是默认的fact，如果要通过系统没有的fact应当如何实现呢,后面《Puppet扩展篇1-自定义fact结合ENC(hirea)的应用实践》会有介绍

思考：通过变量，尤其是hostname变量确定certname只能保证在hostname不变的情况下才能保证certname不变，否则节点任意修改hostname就会造成certname变更，前期的认证失效，又需要重新认证。那么有没有什么办法解决在hostname变化的情况下certname不变呢，也就是说不需要再次申请证书呢？后面《Puppet扩展篇1-自定义fact结合ENC(hirea)的应用实践》会有介绍。

在模板中引用certname变量注意模板存放的位置要和config.pp中引用模板的位置保持一致

[root@puppetmaster manifests]# vim ../templates/puppet.conf.erb
### config by  puppet ###
[main]
    logdir = /var/log/puppet
    rundir = /var/run/puppet
    ssldir = $vardir/ssl

[agent]
    classfile = $vardir/classes.txt
    localconfig = $vardir/localconfig
    server = <%= scope.lookupvar('puppet::params::puppetserver') %>  #引用变量puppetserver
    certname = <%= scope.lookupvar('puppet::params::certname') %>  #引用变量certname
    runinterval = 10

由于config.pp依赖于params.pp中的变量，所以config.pp中应当应用class puppet::params

3.3.3 确定依赖关系

[root@puppetmaster manifests]# vim config.pp 
class puppet::config{
  include puppet::params   #添加引用关系
  file { '/etc/puppet/puppet.conf':
    ensure  => present,
    content => template('puppet/puppet.conf.erb'),
    owner   => 'root',
    group   => 'root',
    mode    => '0644',
    require => Class['puppet::install'],
  }
}

init.pp中应当包含class puppet::config

[root@puppetmaster manifests]# vim init.pp 
class puppet{
  include puppet::install,puppet::config
}

3.3.4 更新测试

先进行noop测试

[root@agent1 ~]# puppet agent -t --noop
info: Caching catalog for agent1_cert.kisspuppet.com
info: Applying configuration version '1394797763'
notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: 
--- /etc/puppet/puppet.conf    2014-03-10 08:22:33.000000000 +0800
+++ /tmp/puppet-file20140314-7231-f50ehp-0    2014-03-14 19:49:24.000000000 +0800
@@ -1,3 +1,4 @@
+### config by  puppet ###  #添加部分
 [main]
     logdir = /var/log/puppet
     rundir = /var/run/puppet

notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: current_value {md5}fb17740fd53d8d4dfd6d291788a9bda3, should be {md5}134bae34adddbf30a3fe02ff0eb3c6a6 (noop)
notice: Class[Puppet::Config]: Would have triggered 'refresh' from 1 events
notice: Stage[main]: Would have triggered 'refresh' from 1 events
notice: Finished catalog run in 0.43 seconds

强制执行更新

[root@agent1 ~]# puppet agent -t 
info: Caching catalog for agent1_cert.kisspuppet.com
info: Applying configuration version '1394797763'
notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: 
--- /etc/puppet/puppet.conf    2014-03-10 08:22:33.000000000 +0800
+++ /tmp/puppet-file20140314-7475-mlybgg-0    2014-03-14 19:50:16.000000000 +0800
@@ -1,3 +1,4 @@
+### config by  puppet ###
 [main]
     logdir = /var/log/puppet
     rundir = /var/run/puppet

info: FileBucket adding {md5}fb17740fd53d8d4dfd6d291788a9bda3
info: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]: Filebucketed /etc/puppet/puppet.conf to puppet with sum fb17740fd53d8d4dfd6d291788a9bda3
notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: content changed '{md5}fb17740fd53d8d4dfd6d291788a9bda3' to '{md5}134bae34adddbf30a3fe02ff0eb3c6a6'
notice: Finished catalog run in 0.34 seconds
[root@agent1 ~]# cat /etc/puppet/puppet.conf
### config by  puppet ###
[main]
    logdir = /var/log/puppet
    rundir = /var/run/puppet
    ssldir = $vardir/ssl

[agent]
    classfile = $vardir/classes.txt
    localconfig = $vardir/localconfig
    server = puppetmaster.kisspuppet.com   #根据预先定的puppetserver变量生成
    certname = agent1_cert.kisspuppet.com  #根据预先定义的certname变量生成
    runinterval = 10

[root@agent3 ~]# puppet agent -t
info: Caching certificate for agent3_cert.kisspuppet.com
info: Caching certificate_revocation_list for ca
info: Caching catalog for agent3_cert.kisspuppet.com
info: Applying configuration version '1394797763'
notice: /Stage[main]/Motd/File[/etc/motd]/content: 
--- /etc/motd    2010-01-12 21:28:22.000000000 +0800
+++ /tmp/puppet-file20140314-2786-1wb4mas-0    2014-03-14 19:51:27.589533699 +0800
@@ -0,0 +1,3 @@
+--                       --
+--------puppet test---------
+--                       --

info: FileBucket adding {md5}d41d8cd98f00b204e9800998ecf8427e
info: /Stage[main]/Motd/File[/etc/motd]: Filebucketed /etc/motd to puppet with sum d41d8cd98f00b204e9800998ecf8427e
notice: /Stage[main]/Motd/File[/etc/motd]/content: content changed '{md5}d41d8cd98f00b204e9800998ecf8427e' to '{md5}87ea3a1af8650395038472457cc7f2b1'
notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: 
--- /etc/puppet/puppet.conf    2014-03-09 01:50:46.112175841 +0800
+++ /tmp/puppet-file20140314-2786-z4e844-0    2014-03-14 19:51:27.719533700 +0800
@@ -1,3 +1,4 @@
+### config by  puppet ###
 [main]
     logdir = /var/log/puppet
     rundir = /var/run/puppet
@@ -8,3 +9,5 @@
     localconfig = $vardir/localconfig
     server = puppetmaster.kisspuppet.com
     certname = agent3_cert.kisspuppet.com
+    runinterval = 10
+    
+    
+    
+    
+     = true

info: FileBucket adding {md5}03cbe6d4def560996eeacedfaef229b4
info: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]: Filebucketed /etc/puppet/puppet.conf to puppet with sum 03cbe6d4def560996eeacedfaef229b4
notice: /Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content: content changed '{md5}03cbe6d4def560996eeacedfaef229b4' to '{md5}4f57479998961563e3306b5d0e02a678'
info: Creating state file /var/lib/puppet/state/state.yaml
notice: Finished catalog run in 2.86 seconds
[root@agent3 ~]# cat /etc/puppet/puppet.conf 
### config by  puppet ###
[main]
    logdir = /var/log/puppet
    rundir = /var/run/puppet
    ssldir = $vardir/ssl

[agent]
    classfile = $vardir/classes.txt
    localconfig = $vardir/localconfig
    server = puppetmaster.kisspuppet.com
    certname = agent3_cert.kisspuppet.com
    runinterval = 10

3.3、编写配置文件service.pp

通过service资源实现，更多有关service资源及案例请访问http://kisspuppet.com/2013/11/12/service/

3.3.1、编写service.pp文件

[root@puppetmaster manifests]# vim service.pp 
class puppet::service{
  service { 'puppet':
    ensure     => running,  #设置puppet服务一直处于运行状态
    hasstatus  => true,  #通过标准的命令“service server_name status"进行检查状态
    hasrestart => true,  #设置puppet服务具有标准的restart命令
    enable     => true,  #要求开机自动启动，其实通过chkconfig设置puppet状态为on
  }
}

3.3.2、更新config.pp文件，增加通知服务重启功能

这个设置完成后，我们再想想我们预先确定的要求是配置在更新后要求puppet服务自动重启，应当做如下设置

[root@puppetmaster manifests]# vim config.pp 
class puppet::config{
  include puppet::params
  file { '/etc/puppet/puppet.conf':
    ensure  => present,
    content => template('puppet/puppet.conf.erb'),
    owner   => 'root',
    group   => 'root',
    mode    => '0644',
    require => Class['puppet::install'],
    notify  => Class['puppet::service'],  #配置更新后主动通过puppet服务重启
  }
}

3.3.3、添加class puppet::service到init.pp中

[root@puppetmaster manifests]# vim init.pp 
class puppet{
  include puppet::install,puppet::config,puppet::service
}

3.3.4、测试

测试一：查看是否设置了开机启动，查看puppet服务状态

[root@agent1 ~]# chkconfig puppet off
[root@agent1 ~]# /etc/init.d/puppet status
puppetd is stopped

[root@agent1 ~]# puppet agent -t
info: Caching catalog for agent1_cert.kisspuppet.com
info: Applying configuration version '1394798692'
notice: /Stage[main]/Puppet::Service/Service[puppet]/ensure: ensure changed 'stopped' to 'running'
notice: Finished catalog run in 1.42 seconds

[root@agent1 ~]# chkconfig --list | grep puppet
puppet             0:off    1:off    2:on    3:on    4:on    5:on    6:off
[root@agent1 ~]# /etc/init.d/puppet status
puppetd (pid  8537) is running...

测试二、查看配置被更改还原后，服务是否会自动重启

[root@agent1 ~]# echo "#add a line" >>/etc/puppet/puppet.conf
[root@agent1 ~]# tailf  /var/log/messages
Mar 14 21:18:52 agent1 puppet-agent[10803]: Reopening log files
Mar 14 21:18:52 agent1 puppet-agent[10803]: Starting Puppet client version 2.7.25
Mar 14 21:18:53 agent1 puppet-agent[10803]: Finished catalog run in 0.27 seconds
Mar 14 21:19:05 agent1 puppet-agent[10803]: Finished catalog run in 0.35 seconds
Mar 14 21:19:16 agent1 puppet-agent[10803]: Finished catalog run in 0.71 seconds
Mar 14 21:19:27 agent1 puppet-agent[10803]: Finished catalog run in 0.30 seconds
Mar 14 21:19:38 agent1 puppet-agent[10803]: Finished catalog run in 0.37 seconds
Mar 14 21:19:50 agent1 puppet-agent[10803]: Finished catalog run in 0.42 seconds
Mar 14 21:20:01 agent1 puppet-agent[10803]: Finished catalog run in 0.28 seconds
Mar 14 21:20:12 agent1 puppet-agent[10803]: Finished catalog run in 0.36 seconds
Mar 14 21:20:23 agent1 puppet-agent[10803]: Finished catalog run in 0.27 seconds
Mar 14 21:20:34 agent1 puppet-agent[10803]: (/Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content) content changed '{md5}898865b650b9af4cae1886a894ce656e' to '{md5}8c67cb8c039bb6436556b91f0c6678c4'
Mar 14 21:20:34 agent1 puppet-agent[10803]: Caught TERM; calling stop
Mar 14 21:20:36 agent1 puppet-agent[13068]: Reopening log files
Mar 14 21:20:36 agent1 puppet-agent[13068]: Starting Puppet client version 2.7.25  #重启服务

3.3.5、服务设置reload动作

在有些场合，我们仅仅需要在修改配置后，让服务重新reload而不是restart，这又当如何设置呢

[root@puppetmaster manifests]# vim config.pp 
    class puppet::service{
      service { 'puppet':
        ensure     => running, 
        hasstatus  => true, 
        hasrestart => true, 
        enable     => true, 
        provider   => init,  
        path       => "/etc/init.d",  #设置启动脚本的搜索路径
        restart    => "/etc/init.d/sshd reload",  #将restart改成reload
        start      => "/etc/init.d/sshd start",
        stop       => "/etc/init.d/sshd stop",
      }
    }

测试可以看出服务并没有停止，而是refresh了

[root@agent1 ~]# echo "#add a line" >>/etc/puppet/puppet.conf 
[root@agent1 ~]# tailf  /var/log/messages
Mar 14 21:32:03 agent1 puppet-agent[13068]: Finished catalog run in 0.33 seconds
Mar 14 21:32:13 agent1 puppet-agent[13068]: Reparsing /etc/puppet/puppet.conf
Mar 14 21:32:14 agent1 puppet-agent[13068]: (/Stage[main]/Puppet::Config/File[/etc/puppet/puppet.conf]/content) content changed '{md5}898865b650b9af4cae1886a894ce656e' to '{md5}8c67cb8c039bb6436556b91f0c6678c4'
Mar 14 21:32:14 agent1 puppet-agent[13068]: (/Service[puppet]) Triggered 'refresh' from 1 events
Mar 14 21:32:14 agent1 puppet-agent[13068]: Finished catalog run in 0.32 seconds
Mar 14 21:32:25 agent1 puppet-agent[13068]: Finished catalog run in 0.25 seconds
Mar 14 21:32:35 agent1 puppet-agent[13068]: Reparsing /etc/puppet/puppet.conf
Mar 14 21:32:36 agent1 puppet-agent[13068]: Finished catalog run in 0.25 seconds

4、优化代码

4.1、将install.pp中的判断语句添加到params.pp中

[root@puppetmaster manifests]# vim params.pp 

class puppet::params {
  $puppetserver = 'puppetmaster.kisspuppet.com'
  case $hostname{
    agent1: {
      $certname = 'agent1_cert.kisspuppet.com'
    }
    agent3: {
      $certname = 'agent3_cert.kisspuppet.com'
    }
    default: {
      fail("certname is not supported on ${::operatingsystem}")
    }
  }

  case $operatingsystemmajrelease{   #添加系统版本变量
    5: {
      $puppet_release = '2.7.23-1.el5'
      $facter_release = '1.7.3-1.el5'
    }
    6: {
      $puppet_release = '2.7.23-1.el6'
      $facter_release = '1.7.3-1.el6'
    }
    default: {
      fail("Module puppet is not supported on ${::operatingsystem}")
    }
  }
}


[root@puppetmaster manifests]# vim install.pp  #通过变量引用
class puppet::install{
  include puppet::puppet_install,puppet::facter_install
}
class puppet::puppet_install{
  package { 'puppet':
    ensure => $puppet::params::puppet_release,  #puppet里引用变量的方法为“$class::子class::变量”
  }
}
class puppet::facter_install{
  package { 'facter':
    ensure => $puppet::params::facter_release,
  }
}

4.2、测试（略）

技术源于分享.....

ssh模块案例详解：http://dreamfire.blog.51cto.com/418026/1257719