Why Puppet?

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The Basics

By scmGalaxy.com

About Me

DevOps@RajeshKumar.XYZ

Problem

A tale of growth...

Add a database

Make database redundant

Application server redundancy

Add a load balancer

Webscale!

Now we need a caching layer

Infrastructure has a Topology

Your Infrastructure is a Snowflake

Complexity Increases Quickly

Puppet Solves this problem

4 Major Challenges for SysAdmin

Why not use script?

• Write
• Test
• Debug

Scripts Take Time

Scripts Are Procedural

Scripts Are Idiosyncratic

• Multiple ways of doing the same thing
• A script written by one person may be indecipherable to another

Script must be written for each Operating
System version or Distribution

• We will talk about Windows Later, lets check it in Linux

Package Managers and Names Differ Across Distributions

Service Managers Differ Across Versions of the Same Distribution

CentOS/RHEL 6

• Upstart
  • restart httpd

CentOS/RHEL7

• systemd
  • systemctl restart httpd

What about Windows?

Windows is not Immune

MP owerShell Script written in version 2
may not natively work in versions 3+

What about Group Policies?

Solution - Puppet

Puppet overcome the shortcomings of other
configuration management approaches

Puppet Programs are Declarative Vs Procedural

Puppet Abstracts Resources

• A single Puppet program can work on different operating systems and distributions

One Puppet Master to Rule Them All

Other Tools…

• What about other configuration management systems?

InfoWorld ScoreCard(2013)

CFEngine and Chef

CFEngine

• Complex
• Behaves differently across operating systems

Chef

• Requiresknowledgeof Ruby

Puppet is used by

End of this session

What is Puppet?

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Puppet manages your infrastructure. You describe configurations in an easy-to-read declarative language, and Puppet will bring your systems into the desired state and keep them there.

You have a problem.

But there is a solution.

End of this session

So what's really gonig on?

So what's really gonig on?

DESIRED STATE

What is Puppet Enterprise?

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At the end of this course you will be able to:

• Explain what Puppet Enterprise is.
• List the benefits of using Puppet Enterprise.

• Puppet Enterprise is IT automation software that gives system administrators the power to easily automate repetitive tasks, quickly deploy critical applications, and proactively manage infrastructure, on-premises or in the cloud.
• Puppet Enterprise automates tasks at any stage of the IT infrastructure lifecycle, including: discovery, provisioning, OS & app configuration management, orchestration, and reporting.

Puppet Concept

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Prerequisite Knowledge

• Basic Linux Administration from the shell

  • Text editing
  • SSH

Puppet Architecture

Puppet Master

Nodes

Master and Nodes

Individual configuration items are called resource declarations

Resource Declaration Answer following….

Resource Declaration

Types

Type - Title

Type – Title - Attributes

						    

	node 'apserver'{
	Package {'ntp':
	ensure => installed,

	}
	...
	                       
					   

Package Resource Type

Ensures the ntp package is installed on appserverOl

Resource Title

File resource type

Service resource type

						    
 ...
	service { 'ntpd':
	ensure => 'running',
	enable => true,
	}
   }
	                       
					    

Service Resource Type

Ensures the ntpd service is enabled and running

Resource Attributes

Resource Providers

Providers for the Package resource Type

Creating Manifest

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Elements of a Puppet Manifest

The node.pp Manifest

Stored in /etc/pu ppet/environ ments/prod uction/manifests

Puppet automatically loads all .pp files in the manifests directory

Creating a nodes.pp Manifest

						    
	$ sudo nano
	/etc/puppet/environments/production/manifests/nodes . pp
	
	node 'wiki'{
	}
	
	node 'wikitest'{
	}
	                       
					   

What Is the Goal?

Create a simple text file on each

Puppet node that says/’Created by

Puppet”followed bya timestamp

Resource Type – File
Managing Files
Goal

Create a simple text file on each

Puppet node that says/’Created by

Puppet”followed bya timestamp

Run from Agent

What about the puppet override the file and for
some reason we need to recover the version>

The Client Filebucket

• Stored on the node in
  /var/lib/puppet/clientbucket by default

Run from Agent

Managing Packages

	package{ 'ntp':
	
	  ensure =>  'installed',
	  
	}

					       

        node 'wiki'{
		
	 file { '/info.txt':
		ensure  => 'present',
		content => inline_template(created by puppet at <%= Time.now %>\n"),
	  }
		package{ 'ntp':
	
	     ensure =>  'installed',
	  }
	}
	node 'wikitest'{
	
		package{ 'ntp':
			ensure =>  'installed',
	  }
	}
					       

Managing Services

	service { 'ntpd':
		ensure => 'running',
		enable => true,
	}
	
	service { 'ntp':
		ensure => 'running',
		enable => true,
	}
			       

Selectors

	 $ntpservice = $osfamily ? {
	 
		'redhat' => 'ntpd',
		
		'debian' => 'ntp',
		
		default =>  'ntp',
	}
			           

Constructing a Selector

• A selector assigns one of a set of possible values to a variable based on a condition

	Replace:
	
	service { 'ntpd':
		ensure => 'running',
		enable => true,
	}
	With:
	
	service { $ntpservice:
		ensure => 'running',
		enable => true,
	}
			             

Classes

DRY = Don’t Repeat Yourself!

Puppet class # object-oriented class

Puppet ciass

A named collection of resource declarations,
variables, selectors, or any other Puppet code

Class Definition and Usage

	class linux {
	
	   package {'ntp':
	   
		ensure => 'installed',
	   }
	}

	node 'wiki' {
	
	   { class 'linux': }
	}
			           

Variables

	class linux {
	
	   $admintoo1s = ['git' 'nano', 'screen']
	   
	    package { $admintoo1s:
		ensure => 'installed',
	   }
	}

			           

Questions?

Thanks for You

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