CloudFormation

Infrastructure as Code on AWS

Essentials

• Pure definition of Infrastructure as Code:

  • You can "convert" you application's architecture into a JSON or YAML formatted template (architecture is literally code)

  • You can then use that JSON/YAML to deploy out updated or replicated copies of that architecture to multiple regions

• Can be built off JSON/YAML templates, either fed in or built in a WYSIWYG tool called the Cloudformation Designer

• Also has many templates with wizards for popular deployments like WordPress or LAMP stack

Benefits

• Saves time - You don't have to manually duplicate architectures

• Version control your infrastructure, allowing for rollbacks to previous versions.

• Backups of infrastructure

• Disaster recovery

CloudFormation Engine

• Create Stack

• Update Stack - Change Sets

  • Has a "diff-ing" tool that allows you to approve suggested changes

  • Templates stack, smaller templates can live in one big template.

• Delete Stack

• Nested Stacks

Template

• Resources

  • Services to deploy, attributes

  • EC2, VPC, Subnet, Security Groups...

  • User Data Script

  • Custom Resources

• Parameters

  • Variables in template

  • User prompted for values at run time

  • Key Pair, Instance Type, DB Password, etc.

• Mappings

  • Lookup Table

  • AMIs by Region

• Conditions

  • Define if a resource will be created

  • Environment = PROD

• Outputs

  • Information to Return about Stack

  • ELB DNS Name

Help Scripts

• cfn-init (CloudFormation Init)

  • packages

  • users, groups

  • files

  • commands, services

• cfn-signal

  • user with wait conditions and creation policies

  • Signals that will be sent back to CloudFormation

• cfn-hup

  • in place instance update of packages and software

  • changes to metadata