Cloud Formation Template

• CF Template gives easier way to create aws application/infrastructure creational/update templates.

• It allows us to define parameters

• Template can be shared with others to create the application/infra in any account.

• CF Templates can be called from CI/CD Engines like jenkins

• CF Template can be written for any service to create any resource.

• CF Templates can be written in

  • JSON
  • YAML

• Example Scenario: Create the following in AWS

• Evaluate the Scenario:

  • Console: Creation is simple but repetition can be difficult
  • CLI: Scripting might require some prior knowledge, but changes will be difficult to handle in repetition
  • CF Template: Create is time consuming but repetition is effective and easy.

Cloud Formation Basics

• Template: JSON/YAML file which has resources, parameters etc
• Resource: Any thing which can be created in AWS
• Parameter: Input from user
• Output: result of execution of Template
• Stack: Stack is required for execution of Template.

Cloud Formation Syntax

• Refer Here for official docs
• Refer Here for template structure
• Refer Here for directdevops.blog reference.
• JSON Syntax

{
  "AWSTemplateFormatVersion" : "version date",

  "Description" : "JSON string",

  "Metadata" : {
    template metadata
  },

  "Parameters" : {
    set of parameters
  },

  "Mappings" : {
    set of mappings
  },

  "Conditions" : {
    set of conditions
  },

  "Transform" : {
    set of transforms
  },

  "Resources" : {
    set of resources
  },

  "Outputs" : {
    set of outputs
  }
}

• Sample Minimal Template

{
  "AWSTemplateFormatVersion" : "2010-09-09",
  "Description" : "learning cf",
  "Resources": {

  }
}

Sample AWS CF Template for Creating S3 bucket

• Manually create a S3 bucket to understand the approach.
• Create a directory and create a json file in this with following content

{
  "AWSTemplateFormatVersion" : "2010-09-09",
  "Description" : "learning cf",
  "Resources": {

  }
}

• Now since we are supposed to create a s3 resource, google aws cloudformation s3 bucket
• Now click and open the aws docs which has the resource structure/syntax defined.
• The following content will be enough to create s3 bucket

{
    "AWSTemplateFormatVersion" : "2010-09-09",
    "Description" : "learning cf",
    "Resources": {
        "mys3": {
            "Type" : "AWS::S3::Bucket",
            "Properties": {
                "BucketName": "qt-s3-learning-forcf.com"
            }
        }
    }
}

• Now navigate to CLoudformation Service and Create stack by uploading the above template.

Dev Environment Setup

• From here Refer Setting up your machine for AWS CloudFormation section