Puppet Files Templates

by scmGalaxy.com

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DevOps@RajeshKumar.XYZ

Puppet 4: Working with Files and Templates

PUPPET FILE AND TEMPLATE TOOLS

Module Overview

Lab Environment
Pluralsight Courses
Course Contents

Lab Environment

Puppet 4 Series

This course follow on from the Puppet 4: Modules and Classes course. In this course you will learn to rationalize the use of files using templates. Making better use of variable content.

Working with Template Reduces the files Needed


	Template: ntp.conf.erb
	server <%= @server_address %>

File Tools

Working with tools such as the function file_line we do not necessarily need to manage a complete file. We can ensure a given line is present or absent from the file.

Puppet 4: Language Essentials
Puppet 4: Working with Modules and Classes
Puppet 4: Working with File and Templates
Puppet 4: Hiera the Single Source of Truth
Puppet 4: Server and Puppet Enterprise

Puppet 4: Working with Files and Templates

Installing a puppet module from an archive

Summary

Next up: Using Puppet Templates

Using Puppet Templates

Objectives

Why use templates
ERB vs EPP templates
Using inline templates

Why Use Templates

Using a template allows us to implement variable data
within a single file


	server 192.168.0.3  
	server uk.pool.ntp.org


	server <%= @ntp_local_server %> 
	server <%= @ntp_regional_server %>

Static Files vs Templates

Instead of hard coding values into files, templates make use of
variable data. The @ symbol used here for the variables tells us that the template is written in the ERB or Embedded Ruby Language.

EPP vs ERB

Using Templates

Functions: epp = read a template inline_epp = read a string	Functions: template = read a template inline_template = read a string
EPP	ERB

Working with Inline ERB Templates

Simple MOTD Manifest


	$down_time = ‘17:00’
	$motd = @(END)
	Welcome to the server: <%= @facts[‘networking’][‘fqdn’] %> 
	The server will be down today at: <%= @down_time %> 
	END

	file { ‘/etc/motd’:  
	ensure	=> ‘file’,
	content => inline_template($motd),
	}

Working with Inline EPP Templates

Simple MOTD Manifest


	$motd= @(END)
	Welcome to the server: <%= $facts[‘networking’][‘fqdn’] %>  
	The server will be down today at: <%= $down_time %>  
	END
		
	file { ‘/etc/motd’:  
	ensure	=> ‘file’,
	content => inline_epp($motd, {‘down_time’=> ’17:00’},),
	}

Embedded ruby code in ERB templates

Embedded puppet code in EPP templates which is new to puppet 4

ERB files can use template or inline_template functions

EPP files can make use of the epp function or inline_epp function.

Next up: Working with ERB Templates

Working with ERB Templates

Objectives

Creating the templates directory
Creating an ERB template using expression printing tags
Adding if statement in code tags
Adding iteration to code tags
Validating ERB templates

Templates Directory

When using templates with modules they should be
located in the /template/directory.
They can be accessed using the template or epp function


	cd /etc/puppetlabs/code/environments/production/modules
	sudo mkdir ntp/templates  
	sudo mv ntp/files/ntp.conf ntp/templates/ntp.conf.erb 
	sudo rm ntp/files/*

Copy the ntp. conf to the Templates Directory

We can now rationalize the amount of configuration files we use removing the files and using just one template

Configure the Templates Directory

Simple ntp.conf.erb with Expression Tags


	#Managed by Puppet - do not edit
	server <%= @ntp_local_server%> iburst prefer
	server <%= @ntp_regional_server%> 
	driftfile /var/lib/ntp/drift

Create the Initial ERB Template

Setting Variables


	#ntp/manifests/admin_file.pp
	$ntp_regional_server = $ntp_location ? {
	'London' => 'uk.pool.ntp.org',
	'paris'  => 'fr.pool.ntp.org',
	'nyc'    => 'us.pool.ntp.org',
	default  => 'pool.ntp.org',
	}
	
	$ntp_local_server = '192.168.0.3'

File Resource


	#ntp/manifests/admin_file.pp  
	file { $title :
	content => template('ntp/ntp.conf.erb')
	…
	}

Using the Initial ERB Template

Adding Logic with Non-printing Tags


	#Managed by Puppet - do not edit
	server <%= @ntp_local_server %> iburst prefer
	server <%= @ntp_regional_server %>
	driftfile /var/lib/ntp/drift
	
	<% if @monitor == false -%>
	disable monitor
	<% end -%>

Adding Logic to the Template

Iteration


	#ntp/manifests/admin_file.pp
	$ntp_regional_server = $ntp_location ? {
	'London' => ['uk.pool.ntp.org', 'ie.pool.ntp.org',]
	'paris'  => ['fr.pool.ntp.org', 'de.pool.ntp.org',]
	'nyc'    => ['us.pool.ntp.org', 'ca.pool.ntp.org',]
	default  => ['pool.ntp.org',    'us.pool.ntp.org',]
	}


	#Managed by Puppet - do not edit
	server <%= @ntp_local_server -%> iburst prefer
	
	<% @ntp_regional_server.each do |s| -%>
	server <%= s -%>
	<% end %>

	driftfile /var/lib/ntp/drift
	<% if @monitor == false -%>
	disable monitor
	<% end -%>

Adding Iteration to the Template

Validating ERB Templates

We need to use the erb and the ruby command.

These are in /opt/puppetlabs/puppet/bin which is not in the PATH variable by default

./erb -Pxt '-' | ./ruby -c

Templates should be located in /template/subdirectory.

An ERB template has embedded ruby tags.

Expression tags print a value: <%=....%>

Code tags embed ruby code: <%=....%>

If the closing tag includes the - symbol then we supress the line feedas as long as no further characters follow the closing tags.

Next up: Working with EPP Templates

Working with EPP Templates

Objectives

Creating an EPP template using expression printing tags
Adding if statement in code tags
Adding iteration to code tags
Validating and rendering EPP templates

Simple ntp.conf.epp with Expression Tags


	#Managed by Puppet - do not edit
	server <%= $ntp_local_server%> iburst prefer
	server <%= $ntp_regional_server%> 
	driftfile /var/lib/ntp/drift

File Resource


	#ntp/manifests/admin_file.pp  
	file { $title :
	content => template('ntp/ntp.conf.epp')
	…
	}

Adding Logic with Non-printing Tags


	#Managed by Puppet - do not edit
	server <%= @ntp_local_server %> iburst prefer
	server <%= @ntp_regional_server %>
	driftfile /var/lib/ntp/drift
	
	<% unless $monitor == true -%>
	disable monitor
	<% }-%>

Iteration


	#Managed by Puppet - do not edit
	server <%= @ntp_local_server -%> iburst prefer
	
	<% $ntp_regional_server.each  |$server| { -%>
	server <%= s %>
	<% } -%>

	driftfile /var/lib/ntp/drift
	<% unless $monitor == true { -%>
	disable monitor
	<% } -%>

Refactoring to EPP Template

Validating EPP Templates

This is much more simple than ERB templates.

sudo puppet epp validate

Render EPP Templates

We can even test the output of EPP files.

sudo puppet epp render

If you need to pass value through:

...epp render -- values '{m=>3}'

Validating and Rendering EPP Files

Templates should be located in /templates/subdirectory.

EPP templates work with the puppet 4 client and later.

Variables within the EPP file are local to the template, these can be populated by passing parameters when accessing the template.

We can use the Puppet client to both validate and render the template.

Next up: Delivering Files with Puppet

Delivering Files with Puppet

Objectives

Introduction to purging resources
Managing the local host file
Delivering directories and content

ensure => 'present',

purge => true,

Resource: resources


	resources { 'host':
	purge => true,
	noop  => true,
	}

Host Resource Type


	host { $facts['networking']['fqdn']:  
	ip => $facts ['networking']['ip'],
	}
	
	unless $facts['networking']['fqdn'] == 'centos7' {
	host { 'centos7':
	ip => '192.168.56.15',
		}
	}

Encapsulate Repetitive Code Using Defined Type


	host { $facts['networking']['fqdn']:  
	ip => $facts ['networking']['ip'],
	}
	
	host_entries::host_entry { 'centos7':
	ip => '192.168.56.15',
	}

Defined Type


	define host_entries::host_entry (
	$ip,
	){
		
	unless $facts['networking']['fqdn'] ==  $title {
	host { $title :
	ip => $ip,
			}
		}
	}

Managing the Host File on CentoOs and Ubuntu

Copy a directory

and content

Copy Directory


	file { ‘/etc/yum.repos.d/’:
	ensure => 'directory',
	source => 'puppet:///modules/centos_repo/repos/',
	recurse => true,
	purge => true,
	}

Managing CentoOs Repository Files

Meta-resource

The meta-resources resources can manage meta-parameters for the given resource type.


	resource {'host':
	purge => true,
	}

Encapsulate Repetitive Logic in Defined Types

Repetitive logic can be encapsulated within defines types.


	define host_entries:: host_entry(
		$ip,
	){
	unless $fact ['fqdn'] == $title{
		host { $title:
		ip => $ip,
	}}}

Using source within a file resource we can copy a file or directory.

Using resource will copy a directories content.

Using purge we can ensure only the delivered content will exist.

Next up: Ensure Content Using File_Line

Ensure Content Using File_Line

Objectives

Investigate Puppetlabs Stdlib
Utilize file_line to ensure file content
Build MOTD module

Without Fail Install

puppetlabs/stdlib

validation & Encryption

and now file_line

Stdlib Documentation on Puppet Forge


	file_line { '/etc/ssh/sshd_config':
	line => 'PermitRootLogin yes',
	}

Undesirable Complete File Management

Where we do not wish to manage the complete file we can allow a level of autonomy whilst controlling the setting needed. The example used here matches the complete line and ensures it is present in the file.


	File_line { path => 'etc/ssh/sshd_config', }  
	file_line { 'PermitRootYes':
	line => 'PermitRootLogin yes',
	}
	file_line { 'PermitRootNo':
		line => 'PermitRootLogin no',
		ensure = 'absent',
	}

Independent Title

Setting a title to be independent of the path allows for more than one line in the same file to be managed.


	File_line { path => 'etc/ssh/sshd_config', }
	file_line { 'PermitRootYes':
	line	=> 'PermitRootLogin yes',
	match   => '^\s*PermitRootLogin\s+yes'
	}

Using Regular Expressions

Matching the whole line as we have used sa far will be problematic where extra white spaces are used. Using match we can implement regular expression.

Regular Expression Fundamentals - Juliette Reinders Folmer

Managing the SSH Server Configuration

Challenge

The MOTD file should be managed independently on all servers.

Planned downtime for a server will occur at 17:00 on the selected day.The message for the downtime must be consistant across all servers.

Produce a Puppet solution for this using the file_line type from the stdlib.

Using the file_line type from the stdlib.

Using line we will match the complete line.

Using match we can use regular expression.

Use match_for_absence => true when using match for deletions.

Possible Challenge Solution

Next up: Delivery of File Parts with Concat

Questions

Thank you!