Ref: https://learn.cantrill.io/courses/1820301/lectures/41301626

YouTube: https://www.youtube.com/watch?v=ptvce7lJ6Z0

DEMO: https://learn.cantrill.io/courses/1820301/lectures/41301627

• Summary
• Contents:

IaC basics and AWS CloudFormation

• IaC = Infrastructure as Code
  • Create, update & delete infrastructure using code and/or templates
  • Code/Templates are consistent and repeatable
    • Reduces human errors
    • Much faster to provision/delete infrastructure than manually
• 🔧 AWS CloudFormation (CFN) is the AWS official IaC product
  • Templates written in YAML or JSON to interact with infrastructure inside AWS
  • 💡 Nowadays very popular to use external IaC products like Terraform or CDK, which use/translate to AWS CFN templates to interact with AWS infrastructure

CFN Templates - Example and Components

• 💡 By default CFN templates are uploaded to an S3 bucket with prefix CF

  • ‼️ Despite the prefix, do NOT confuse CFN (CloudFormation) with CF (CloudFront)!!

• Template example in YAML:

  

• Resources → AWS resources to create/update/delete

  • e.g. VPCs, S3 buckets, EC2 instances…
  • ‼️ This is the only component in a template that is mandatory!
    • without resources, a template doesn't do anything
  • ❗ Resources listed in a template/stack are logical resources

• AWSTemplateFormatVersion → Version date of the template

• Description → Free text, can be used to describe what the template does

  • ❗ If description is provided, it must appear after AWSTemplateFormatVersion

  

• Metadata → Controls how the template is shown in AWS UI

  

• Parameters → Fields that prompt the user for required information

  

• Mappings → Key-value pairs that can be used for lookups

  

• Conditions → Bind resources to specific conditions (”only do X if Y”)

  • Conditions will appear under Resources if they affect those resources
  • e.g. create an EC2 instance only if we are in PROD environment