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 ```yaml - 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 ```puppet 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 ```ruby 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 ```hcl 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