JSON and YAML

• They are data representational formats
• Both JSON and YAML use key value pairs to represent data
• Both JSON and YAML have 3 types of data which we can represent
  • Simple/Scalar:
    • Text
    • Number
    • Boolean
  • Plural/List
  • Object/dictionary
• JSON
• YAML

Developing Cloud formation Templates

• When developing Cloudformation template we can use json or yaml.
• The structure of the template is defined by AWS Refer Here
• JSON structure Refer Here

{
  "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 structure Refer Here

---
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

• Refer Here for template sections
• Minimal Template in JSON

{
    "Resources": {}
}

• Minimal Template in YAML

---
Resources:

• Each resource can be defined in the resource section by the following syntax Refer Here

Activity-1: Hello Cloudformation in JSON

• Ensure Visual studio code is installed.
• Create a new folder and open this with vs code
• Install cloudformation extension into visual studio code
  
• Create a new file template.json
• Now since we want to create vpc google aws vpc cloudformation and open the section as shown below
  
• Refer Here for the syntax
• Navigate to each property and verify the highlighted sections
  
• The template which we developed is

{
    "Resources": {
        "myvpc": {
            "Type": "AWS::EC2::VPC",
            "Properties": {
                "CidrBlock": "192.168.0.0/16",
                "Tags": [
                    {
                        "Key": "Name",
                        "Value": "activity1-vpc"
                    }
                ]
            }
        }
    }
}

• Now we have template, when we execute template what we create is referred as stack in cloudformation.
  
  
• Continue till create stack
  
  
  
  
• Refer Here for the changes
• To cleanup delete the stack
• The same template in YAML is as shown below

---
Resources:
  myvpc:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 192.168.0.0/16
      Tags:
        - Key: Name
          Value: activity1-vpc