AWS Classroomnotes 25/Mar/2023

Infrastructure as Code (IaC)

This represents expressing infra as a Desired state and let the IaC tool do the rest.
Popular IaC tools
- Terraform
- Cloud Formation
- ARM Templates
- Azure Bicep

AWS Cloudformation

AWS Cloudformation, allows us to express the desired state in json or yaml format and when executed (Created stack) will create infra
Workflow
- Author a template
- upload to s3 directly or indirectly
- Creates changeset (what has to be created/updated)
- Executes to realize infra.
Refer Here for CF concepts
Template: Desired state expressed in json or yaml
Stack: Represents the execution of Template
Changeset: This represents the infra to be updated/created/deleted.
To author an Cloud formation template
- JSON/YAML Knowledge
- Manual steps of how to create infra
- Productivity:
  - Visual Studio Code with Cloudformation extension

Cloudformation Template Grammar/Syntax

Refer Here for AWS CF Template syntax
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
  }
}

YAML

---
AWSTemplateFormatVersion: "version date"

Description:
  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

Template sections Refer Here
For now lets look at three template secions
- Format Version: Refer Here
- Description Refer Here
- Resources Refer Here
Skeleton(json):

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

    }
}

Skeleton (YAML):

---
AWSTemplateFormatVersion: '2010-09-09'
Description: ''
Resources: {}

Activity 1: Create an S3 bucket using Cloud formation

Way of Working (WoW):
- Manual steps for creation
- Lets make a note of inputs which we provide while creating s3 bucket
Manual Steps:
Search for resource type and syntax
s3 resource in cloud formation Refer Here
Refer Here for the template created
Create stack: