AWS06: CloudFormation (Provision VPC and Internet gateway)

Description: 

CloudFormation is aws feature that helps you create, setup and manage infrastructure resources on aws more efficiently.
You compose template, and CloudFormation handles it for provisioning resources as described in the template.
Construct infrastructure with CloudFormation can be done either by design console on aws or uploading prepared JSON/YAML template.

Tutorial:

Let's check how it works step by step.
We will setup webserver infrastructure which consists of 1 vpc, 2 subnets and webservers within it.
And templates would be following:

1. cf-vpc -------------------- Template defines VPC and Internet gateway.
2. cf-subnets --------------- Template defines subnets and route table.
3. cf-securitygroups ------- Template defines security groups.
4. cf-webserver ------------ Template defines EC2 instances, including bastion host.
5. cf-loadbalancer --------- Template defines application load balancer.

In below template, VPC and Internet gateway are defined with "Resources" section.
At the same time, Internet gateway is associated with VPC.
"Outputs" defines the resources which will be referred by another template.

{
    "AWSTemplateFormatVersion": "2010-09-09",
    "Resources" : {
      "VPC" : {
        "Type" : "AWS::EC2::VPC",
        "Properties" : {
          "EnableDnsSupport" : "true",
          "EnableDnsHostnames" : "true",
          "CidrBlock" : "10.0.0.0/24",
          "Tags" : [ { "Key" : "Name", "Value" : "VPC01"} ]
        }
      },
      "InternetGateway" : {
        "Type" : "AWS::EC2::InternetGateway",
        "Properties" : {
          "Tags" : [ { "Key" : "Name", "Value" : "IntGW01" } ]
        }
      },
      "VPCGatewayAttachment" : {
         "Type" : "AWS::EC2::VPCGatewayAttachment",
         "Properties" : {
           "VpcId" : { "Ref" : "VPC" },
           "InternetGatewayId" : { "Ref" : "InternetGateway" }
         }
      }
    },
    "Outputs" : {
      "VPCId" : {
        "Description" : "VPC ID",
        "Value" :  { "Ref" : "VPC" },
        "Export" : { "Name" : {"Fn::Sub": "${AWS::StackName}-VPCID" }}
      },
      "InternetGateway" : {
        "Description" : "InternetGateway",
        "Value" :  { "Ref" : "InternetGateway" },
        "Export" : { "Name" : {"Fn::Sub": "${AWS::StackName}-InternetGateway" }}
      }
    }
}

See more detailed information of each element on here.

Here's a video tutorial for this.