Activity 2: Creating an Ntier Architecture using CF Template

• Lets start the template, to create the following
  
• For manual steps refer classroom video
• inputs =>
• vpc cidr range => 192.168.0.0/16
• Refer Here for cloud formation template anatomy
• Refer Here for cloud formation vpc
• Refer Here for the changeset for vpc
• Lets create the stack
  
  
• Generally we write templates so that we can reuse.
• To make reusability more effecient, we should paramterize.
• In Cloudformation, we can add parameters Refer Here
• The syntax of paramer is as follows

"Parameters" : {
  "ParameterLogicalID" : {
    "Type" : "DataType",
    "ParameterProperty" : "value"
  }
}

• To use the parameter value syntax is { "ref": "<parameter-name>" }
• In the documentation when we see the Parameter with Update Requires
• Replacement: When we change this value the resource will be recreated
• No interruption: When we change this value the existing resource will be updated withour recreation
• Refer Here for the changes done, Now lets update the cf stack
  
  
  
• There are naming conventions for giving parameter names
• Now lets update the template with fix Refer Here
  
• Now lets Enable DNS Hostnames for VPC. Refer Here
  
• For YAML Lovers refer below

---
AWSTemplateFormatVersion: '2010-09-09'
Description: This is template for activity 2
Parameters:
  vpccidr:
    Description: This is cidr for vpc
    Type: String
    Default: 192.168.0.0/16
Resources:
  ntiervpc:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock:
        Ref: vpccidr
      EnableDnsHostnames: true
      Tags:
      - Key: Name
        Value: Ntier