Configuration Management is the process of maintaining systems, such as computer systems and servers, in a desired state. It's a way to make sure that a system performs as it's supposed to as changes are made over time.

Key aspects include:
- System configuration
- Application configuration
- Dependencies management
- Version control
- Compliance and security

Puppet is a configuration management tool that helps you automate the provisioning and management of your infrastructure. It uses a declarative language to describe system configurations.

Example of a Puppet manifest:
<div class="code-block" data-lang="puppet"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="na">apache</span><span class="w"> </span><span class="p">{</span>

package { 'apache2':
ensure => installed,
}

service { 'apache2':
ensure => running,
enable => true,
require => Package['apache2'],
}

file { '/var/www/html/index.html':
ensure => file,
content => 'Hello, World!',
require => Package['apache2'],
}
}