Learn to work with the most fundamental services AWS offers such as DynamoDB, S3, and EC2 to create reliable and scalable systems.

Scalability & System Design for Developers

In this module, we’ll learn to work with the most fundamental services AWS offers, such as DynamoDB, S3, and EC2 to create reliable and scalable systems. Walk through getting a basic web application running in the cloud on AWS. You won’t find most of the knowledge that's shared here in the AWS docs.

The Good Parts of AWS: Cutting Through the Clutter

## Objective
Make our instances inaccessible from the internet.
 

## Steps
- Add private subnets with a NAT gateway.
- Switch our ASGs to use the private subnets.

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## Add private subnets and NAT gateway

Now, we’re going to add new security groups for our private subnets that allows ports 22 and 8443 only.

# Objective
Make our instances inaccessible from the internet.
 

# Steps
- Add private subnets with a NAT gateway.
- Switch our ASGs to use the private subnets.

---

# Add private subnets and NAT gateway

Now, we’re going to add new security groups for our private subnets that allows ports 22 and 8443 only.

PrivateSecurityGroup:
  Type: AWS::EC2::SecurityGroup
  Properties:
    VpcId: !Ref VPC
    GroupDescription:
      !Sub 'Internal Security group for ${AWS::StackName}'
    SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 8443
        ToPort: 8443
        CidrIp: 0.0.0.0/0
      - IpProtocol: tcp
        FromPort: 22
        ToPort: 22
        CidrIp: 0.0.0.0/0
    Tags:
      - Key: Name
        Value: !Ref AWS::StackName

Next, we have to change the `SecurityGroupIds` property inside the `InstanceLaunchTemplate` resource, so that it refers to `PrivateSecurityGroup.GroupId` instead of `SecurityGroup.GroupId`. In this way, new instances automatically become part of our new private security group.

Part 1: The Good Parts

Part 2: The Bootstrap Guide

Network Security: Add Private Subnets with NAT Gateway

Objective

Steps

Add private subnets and NAT gateway #