puppet基础学习(一)

puppet基础学习(一)

一、 Installation(模块安装)

模块安装地址：

开源版
puppet agent --configprint modulepath
/etc/puppet/environments/production/modules:/etc/puppet/environments/common:/etc/puppet/modules:/usr/share/puppet/modules

企业版
/etc/puppetlabs/puppet/modules/

模块下载地址：

https://forge.puppetlabs.com/puppetlabs?utf-8=✓&supported=yes

安装模块命令：

puppet module install puppetlabs-apache

卸载模块命令：

puppet module uninstall puppetlabs-apache

fact 一条节点的信息，例如操作系统、主机名、ip等

facter命令：获得ip地址：

facter ipaddress

配置立即生效：节点执行命令

puppet agent --test

agent守护进程在用puppet管理的节点上的后台运行，agent守护进程默认每30分钟从puppetmaster获得一个目录，然后应用获得的目录

查看版本信息

puppet -V # That's a capital 'V'

二、Resource(资源)

描述一个资源的puppet编码块称为资源声明，用puppet的自己DSL语言编写（DSL:特定域语言DomainSpecific Language），最后的逗号严格来说不是必须的，但为了一致性最好包含。

 

查看特定资源的工具：

puppet describe
puppet resource

例如：查看user资源类型，puppet describe user
例如：查看user root的资源属性，puppet resource user root

最经常接触的资源

• user：A user
• group： A user group
• file： A specific file
• package： A software package
• service： A running service
• cron： A scheduled cron job
• exec： An external command
• host： A host entry

了解更多资源参考 http://docs.puppetlabs.com/references/latest/type.html

资源案例分析user

user { 'root': # user是资源类型，’root’是资源标题，必须是唯一的，同一个class中不能有同样的资源和标题
  ensure             => 'present',
  comment            => 'root',
  gid                => '0',
  home               => '/root',
  password           => '$1$jrm5tnjw$h8JJ9mCZLmJvIxvDLjw1M/',
  password_max_age   => '99999',
  password_min_age   => '0',
  shell              => '/bin/bash',
  uid                => '0',
}

资源案例分析file

[root@learn /etc/puppetlabs/puppet/modules]# puppet resource file /home/byte/tools
file { '/home/byte/tools':
  ensure => 'absent',#不存在
}
[root@learn /etc/puppetlabs/puppet/modules]# puppet resource file /home/byte
file { '/home/byte':#以下输出了文件信息，目录也是文件的一种
  ensure => 'directory',
  ctime  => '2014-06-30 15:38:06 +0000',
  group  => '501',
  mode   => '700',
  mtime  => '2014-06-30 15:38:06 +0000',
  owner  => '501',
  type   => 'directory',
}

创建目录后，再次执行puppet命令就有该文件信息

[root@learn /etc/puppetlabs/puppet/modules]# mkdir /home/byte/tools
[root@learn /etc/puppetlabs/puppet/modules]# puppet resource file /home/byte/tools
file { '/home/byte/tools':
  ensure => 'directory',
  ctime  => '2014-06-30 15:47:39 +0000',
  group  => '0',
  mode   => '755',
  mtime  => '2014-06-30 15:47:39 +0000',
  owner  => '0',
  type   => 'directory',
}

Resource Abstraction Layer（RAL）

资源抽象层：通过DSL编写的描述资源状态的，可以抽象出来直接定义状态，而不必考虑底层实现的命令，是什么样的操作系统，适用什么样的命令，调用哪些文件，只需把精力花在定义资源的状态即可，providers供应程序可以根据操作系统来实现相应的资源状态。

puppet语言的核心是资源声明

三、 Manifests(清单)

puppet的语法检查器

puppet parser，如果没有指定manifest文件，则默认校验site.pp文件，没有语法错误的时候不会返回信息，否则将会显示第一个语法错误，不过这个不会检查属性跟值的错误，似乎只会检查符号这类。

例如：

[root@learn ~]# more byte.pp #注意格式，写完后用puppet parser validate命令检查
user { 'byte':
ensure => 'absent',
}
[root@learn ~]# puppet parser validate byte.pp
[root@learn ~]#

[root@learn ~]# more byte.pp 
user { 'byte'':
ensure => 'absent',
}
[root@learn ~]# puppet parser validate byte.pp
Error: Could not parse for environment production: Syntax error at ':
ensure => '; expected '}' at /root/byte.pp:2

puppet的执行生效工具
puppet apply：应用并执行自己当前的manifest文件，并在清单文件夹下生成包含所有资源列表和对应状态的目录(catalog)。
puppet apply --noop xxx.pp模拟执行xxx.pp文件，并返回本该会被改变的信息，实际并没有改变。
puppet apply xxx.pp执行xxx.pp文件，并按xxx.pp中的内容，对应将指定的resource发生改变。
例如：

[root@learn ~]# puppet apply --noop byte.pp
Notice: Compiled catalog for learn.localdomain in environment production in 1.35 seconds
Notice: /Stage[main]/Main/User[byte]/ensure: current_value present, should be absent (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 3.22 seconds

[root@learn ~]# puppet apply byte.pp
Notice: Compiled catalog for learn.localdomain in environment production in 1.25 seconds
Notice: /Stage[main]/Main/User[byte]/ensure: removed
Notice: Finished catalog run in 1.60 seconds
#上面已经移除了用户byte，当然，通过将ensure => 'absent',改成ensure => ' present',可以新建用户。

使用自定义pp文件步骤：
1. 打开或创建pp文件
2. 添加或修改puppet代码
3. 使用 puppet parser工具检查语法错误（建议）
4. 使用 puppet apply --noop模拟应用pp文件（建议）
5. 使用 puppet apply工具应用pp文件
6. 检查是否正确执行pp文件

四、 Variables(变量)

变量都带有前缀$，可以将变量作为资源属性的值或者资源标题，变量除了直接赋值外，也可以将表达式或者函数赋给变量。

例如：

$myvariable ="look,data!\n"

再例如：此例子可确保目录pangrams、文件fox.txt存在，内容为变量$pangram的值，即使文件及目录不存在

$pangram = 'The quick brown fox jumps over the lazy dog.'
file {'/root/pangrams':
ensure => directory,
}
file {'/root/pangrams/fox.txt':
ensure => file,
content => $pangram,
}

变量嵌入，嵌入的格式为${var_name}，语法解析器（puppet parser）根据花括号来区分变量和字符串。

注意点：一串字符串用单引号括起来，但是含有变量嵌入的字符串需要用双引号括起来

例如：$pangram = 'Thequick brown fox jumps over the lazy dog.'
例如："Variable interpolation is ${adjective}."

总结变量作用：变量替换和变量插入

例如：两种用法相结合 

创建并维护文件/root/pangrams/perfect_pangrams/bortz.txt及内容
$perfect_pangram = 'Bortz waqf glyphs vex muck djin.'
$pgdir = '/root/pangrams'
file { $pgdir:
ensure => directory,
}
file { "${pgdir}/perfect_pangrams":
ensure => directory,
}
file { "${pgdir}/perfect_pangrams/bortz.txt":
ensure => file,
content => "A perfect pangram: \n${perfect_pangram}", ######其中，\n表示换行
}
执行结果参考如下：（用上述代码创建文件perfect_pangrams.pp）
[root@learn ~]# puppet parser validate perfect_pangrams.pp 
[root@learn ~]# puppet apply --noop perfect_pangrams.pp 
Notice: Compiled catalog for learn.localdomain in environment production in 0.49 seconds
Notice: /Stage[main]/Main/File[/root/pangrams/perfect_pangrams]/ensure: current_value absent, should be directory (noop)
Notice: /Stage[main]/Main/File[/root/pangrams/perfect_pangrams/bortz.txt]/ensure: current_value absent, should be file (noop)
Notice: Class[Main]: Would have triggered 'refresh' from 2 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 0.77 seconds
[root@learn ~]# puppet apply perfect_pangrams.pp                                                                                                                       
Notice: Compiled catalog for learn.localdomain in environment production in 0.17 seconds
Notice: /Stage[main]/Main/File[/root/pangrams/perfect_pangrams]/ensure: created
Notice: /Stage[main]/Main/File[/root/pangrams/perfect_pangrams/bortz.txt]/ensure: defined content as '{md5}4a263fbd94944ab2c67cb291cd1ea089'
Notice: Finished catalog run in 0.93 seconds
[root@learn ~]# more pangrams/perfect_pangrams/bortz.txt 
A perfect pangram: 
Bortz waqf glyphs vex muck djin.
[root@learn ~]#

内置变量（facter facts）

puppet有一堆内置，预设的变量可供使用（使用facter工具可查看）

用法1：$::ipaddress，作为独立变量时

用法2：${::ipaddress}，用于嵌入字符串时

其中，::在上述表示区域，上述都表示全局下的ipaddress变量。

 

例如：使用资源notify，全局变量 ${::osfamily} 、${::uptime} 

创建维护message.txt文件及内容
$string = "Hi, I'm a ${::osfamily} system and I have been up for ${::uptime}
seconds."
notify { 'info':
message => $string,
}
file { '/root/message.txt':
ensure => file,
content => $string,
}
执行结果参考如下：
[root@learn ~]# puppet describe notify
notify
======
Sends an arbitrary message to the agent run-time log.
Parameters
----------
- **message**
    The message to be sent to the log.
- **name**
    An arbitrary tag for your own reference; the name of the message.
- **withpath**
    Whether to show the full object path. Defaults to false.
Valid values are `true`, `false`.
[root@learn ~]# puppet resource notify info #这个info是apply后的notice里面的提示，所以此命令报错。
Error: Could not run: notify has no providers and has not overridden 'instances'
[root@learn ~]# puppet parser validate facts.pp                                                                                                                        
[root@learn ~]# puppet apply --noop facts.pp                                                                                                                           
Notice: Compiled catalog for learn.localdomain in environment production in 0.40 seconds
Notice: /Stage[main]/Main/File[/root/message.txt]/ensure: current_value absent, should be file (noop)
Notice: /Stage[main]/Main/Notify[info]/message: current_value absent, should be Hi, I'm a RedHat system and I have been up for 1:47 hours
seconds. (noop)
Notice: Class[Main]: Would have triggered 'refresh' from 2 events
Notice: Stage[main]: Would have triggered 'refresh' from 1 events
Notice: Finished catalog run in 1.52 seconds
[root@learn ~]# 
[root@learn ~]# puppet apply facts.pp                                                                                                                                  
Notice: Compiled catalog for learn.localdomain in environment production in 0.17 seconds
Notice: /Stage[main]/Main/File[/root/message.txt]/ensure: defined content as '{md5}f44ac52be6f6b4d23f6df3bd41380072'
Notice: Hi, I'm a RedHat system and I have been up for 1:47 hours
seconds.
Notice: /Stage[main]/Main/Notify[info]/message: defined 'message' as 'Hi, I'm a RedHat system and I have been up for 1:47 hours
seconds.'
Notice: Finished catalog run in 1.61 seconds
[root@learn ~]# more message.txt 
Hi, I'm a RedHat system and I have been up for 1:47 hours
seconds.
[root@learn ~]#

五、ConditionalStatements(条件语句)

if , unless , case ,selector

额外知识：代码中的warn()函数不会影响代码执行，但会在服务器上以warn级别产生一条信息，fail()类似。

其中，if与unless作用相反，unless只有一个条件并只有是false的时候才执行代码块，条件为真时，不执行当前代码块并离开和往下个代码块执行，if、unless在puppet中与在其他程序中用的方式一样。

if语句

vi conditionals.pp  #创建pp文件，填入下面代码
if $::uptime_hours < 2 {
$myuptime = "Uptime is less than two hours.\n"
}
elsif $::uptime_hours < 5 {
$myuptime = "Uptime is less than five hours.\n"
}
else {
$myuptime = "Uptime is greater than four hours.\n"
}
file {'/root/conditionals.txt':
ensure => present,
content => $myuptime,
}
执行结果
[root@learn ~]# facter uptime_hours
2
[root@learn ~]# puppet parser validate conditionals.pp
[root@learn ~]# puppet apply --noop conditionals.pp
Notice: Compiled catalog for learn.localdomain in environment production in 0.16 seconds
Notice: /Stage[main]/Main/File[/root/conditionals.txt]/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 0.39 seconds
[root@learn ~]# puppet apply conditionals.pp                                                                                                                           
Notice: Compiled catalog for learn.localdomain in environment production in 0.16 seconds
Notice: /Stage[main]/Main/File[/root/conditionals.txt]/ensure: created
Notice: Finished catalog run in 0.52 seconds
[root@learn ~]# more conditionals.txt 
Uptime is less than five hours.
[root@learn ~]#

case 基本的比较用==符号（大小写不敏感时使用），在正则表达式中使用=~（大小写敏感时使用）

defaultcase放在case语句的最后，用于匹配前面case没有匹配到的，相当于if语句中的else，case的用法在puppet中也是与在其他程序中的用法一样。

case语句

vi case.pp  #创建pp文件，填入下面代码
case $::operatingsystem {
'CentOS': { $apache_pkg = 'httpd' }
'Redhat': { $apache_pkg = 'httpd' }
'Debian': { $apache_pkg = 'apache2' }
'Ubuntu': { $apache_pkg = 'apache2' }
default: { fail("Unrecognized operating system for webserver") }
}
file {'/root/case.txt':
ensure => present,
content => "Apache package name: ${apache_pkg}\n"
}
执行结果
[root@learn ~]# puppet parser validate case.pp
[root@learn ~]# puppet apply --noop case.pp
Notice: Compiled catalog for learn.localdomain in environment production in 0.53 seconds
Notice: /Stage[main]/Main/File[/root/case.txt]/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 0.95 seconds
[root@learn ~]# puppet apply case.pp                                                                                                                                   
Notice: Compiled catalog for learn.localdomain in environment production in 0.19 seconds
Notice: /Stage[main]/Main/File[/root/case.txt]/ensure: created
Notice: Finished catalog run in 0.61 seconds
[root@learn ~]# more case.txt 
Apache package name: httpd

上述的pp文件中，根据case得到的变量值$apache_pkg，也可以按下面这么用，这样可以根据不同的系统安装相应的包

package { $apache_pkg :
ensure => present,
}

selector语句

selector 与case有点类似，但与case直接执行一串代码得到值不同，selector是直接指定一个准确的值，不能执行函数，如fail()和warn()等，注意关键符号”?”。（selector有点类似decode()函数的用法）。

例如：根据$::osfamily得到的结果指定值。

$rootgroup = $::osfamily ? {
'Solaris' => 'wheel',
'Darwin' => 'wheel',
'FreeBSD' => 'wheel',
'default' => 'root',
}

vi architecture.pp  #创建pp文件，填入下面代码
file { '/root/architecture.txt' :
ensure => file,
content => $::architecture ? {
'i386' => "This machine has a 32-bit architecture.\n",
'x86_64' => "This machine has a 64-bit architecture.\n",
}
}
执行结果
[root@learn ~]# puppet parser validate architecture.pp 
[root@learn ~]# puppet apply --noop architecture.pp 
Notice: Compiled catalog for learn.localdomain in environment production in 0.16 seconds
Notice: /Stage[main]/Main/File[/root/architecture.txt]/ensure: current_value absent, should be file (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 0.89 seconds
[root@learn ~]# puppet apply architecture.pp                                                                                                                           
Notice: Compiled catalog for learn.localdomain in environment production in 0.51 seconds
Notice: /Stage[main]/Main/File[/root/architecture.txt]/ensure: defined content as '{md5}980bc3112371901629aa46a1501da814'
Notice: Finished catalog run in 1.05 seconds
[root@learn ~]# more architecture.txt 
This machine has a 32-bit architecture.
[root@learn ~]#