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, and 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 Stacks

• A CFN template is a list of logical resources plus all other template components
• 🔧 CFN Stack = living & active representation of all logical resources of a CFN template
  • Generated from a template (contains all its logical resources)
  • Can be executed in an AWS account to create/update/delete infrastructure
    • For every logical resource in the stack, AWS creates/updates/deletes the corresponding physical resource in the AWS account where the stack is executed

CFN Templates - Format 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 format in JSON:

  {
    "AWSTemplateFormatVersion" : "version date",
  
    "Description" : "JSON string",
  
    "Metadata" : {
      template metadata
    },
  
    "Parameters" : {
      set of parameters
    },
    
    "Rules" : {
      set of rules
    },
  
    "Mappings" : {
      set of mappings
    },
  
    "Conditions" : {
      set of conditions
    },
  
    "Transform" : {
      set of transforms
    },
  
    "Resources" : {
      set of resources
    },
    
    "Outputs" : {
      set of outputs
    }
  }
  

• 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
  • Example: a simple template to spin up a small EC2 instance with an IO1 EBS volume

• AWSTemplateFormatVersion → Version date of the template