Configuration Management Sysadmin

What I do

• Manage server configurations at scale
• Automate infrastructure setup
• Use configuration management tools
• Implement idempotent manifests
• Define desired state
• Ensure configuration compliance

When to use me

When managing infrastructure at scale, automating deployments, or ensuring consistent configurations.

Tools Overview

Ansible

• Agentless
• YAML playbooks
• SSH-based
• Declarative
• Best for: Ad-hoc automation, configuration

- name: Install nginx
  hosts: webservers
  become: yes
  tasks:
    - name: Install nginx
      apt:
        name: nginx
        state: present

Puppet

• Agent-based (master/agent)
• Declarative DSL
• Resource types
• Report drift
• Best for: Long-running infrastructure

package { 'nginx':
  ensure => installed,
}
service { 'nginx':
  ensure => running,
  require => Package['nginx'],
}

Chef

• Agent-based
• Ruby DSL
• Cookbooks and recipes
• Chef Infra, Chef Inspec
• Best for: Complex configurations

package 'nginx' do
  action :install
end

service 'nginx' do
  action [:start, :enable]
end

Terraform

• Infrastructure provisioning
• HCL language
• Plan and apply
• State management
• Best for: Cloud resources

resource "aws_instance" "web" {
  ami           = "ami-12345678"
  instance_type = "t2.micro"
  tags = {
    Name = "WebServer"
  }
}

Key Concepts

Idempotency

• Same result regardless of runs
• Check current state first
• Make minimal changes

Desired State

• Define what, not how
• System reconciles to desired
• Drift detection

Modules/Recipes/Cookbooks

• Reusable components
• Dependency management
• Version control

Testing

• Testinfra
• Serverspec
• Kitchen/CI integration

Best Practices

• Use version control
• Peer review changes
• Test in staging first
• Use secrets management
• Modularize configurations
• Document modules
• Monitor drift
• Backup state files