My first CloudFormation

 

Chris Birchall

CloudFormation

  • Codify your AWS resources
  • Make stack creation reproducible
  • Track and review changes

CloudFormation

  • Describe your resources declaratively in a YAML template
  • Support for parameters, rudimentary logic, string manipulation

Template structure

---
AWSTemplateFormatVersion: 2010-09-09
Description: My lovely template

Parameters:
  ... template parameters ...

Resources:
  ... resources ...

Simple example

---
AWSTemplateFormatVersion: 2010-09-09
Description: My lovely template

Parameters:

  EmailAddress:
    Type: String
    Description: Chris email address

Resources:

  MyLovelyTopic:
    Type: "AWS::SNS::Topic"
    Properties:
      TopicName: send-email-to-chris
      Subscription:
        -
          Protocol: email
          Endpoint: !Ref EmailAddress

Proper example

Cloudforming a Beanstalk app

Disclaimer:

I've never used Beanstalk!

my-amazing-app

  • Dockerized Python app
  • Beanstalk
    • Single environment
    • Single t2.nano instance, immutable deployments
    • EC2 instance profile
    • SSH access only from 10.0.0.0/8
    • HTTP access only via load balancer
    • No public IP on EC2 instance

Recommendations

  • Read the docs, they're surprisingly good
  • You can pass secrets as parameters
    • But don't go crazy with it
  • Use logic sparingly
    • e.g. using an "IsProd" condition to run fewer instances in pre-prod env to save money

Recommendations (2)

  • Don't be tempted to use CloudFormer
    • Cloudforming from scratch is a good opportunity to gain understanding about your resources
  • Do everything manually once before writing template
  • Treat templates as code
    • Pull requests, code reviews
  • Share the love!
    • Copying another team's template is a good way to get started

Recommendations (3)

  • Don't try to make templates too generic
    • Separate template file per service is fine
  • Avoid giving resources custom names
    • Restriction of CloudFormation: some types of resource cannot be updated if they have custom name
  • Run stack updates automatically via CI tool?
    • In my team we don't do this

Go forth and cloudform!

 

Questions?

My first CloudFormation

By Chris Birchall

My first CloudFormation

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