[AWS Solution Architect] Follow Along - Create VPC, IGW, Route Tables and Subnets

Create VPC and Core Components(IGW, Route table, Subnets)

• IPv4 CIDR
  • 10.0.0.0 is commonly chosen one.
  • this is saying how many IP addresses you want to allocate.
• IPv6 CIDR block
  • it’s supported on AWS.
  • it’s the future of our IP protocol.
  • so it’s definitely something you might want to turn on.
  • just be prepared for the future there
• Tenancy
  • dedicated host is quite expensive
• we don’t have any DNS hostnames
  • we definitely want to turn that on.
  • if we launch EC2 instance, it’s not going to get a DNS hostname, that’s just like a URL.

• Create internet gateways
  

• internet gateways can only be attached to a very specific VPC
  • it’s a one-to-one relationship
• but that still doesn’t mean that things within our network can reach the internet
  • because we have to add a route to our route table
• see that there already is a route table associated with our VPC
  • because it did create us a default route table

  

• But let’s create a route table

You can see by default, it has the full scope of our local network here.

• Let change this one to our main.
  • main route table is whenever what is going to be used by default.
• we’re gonna add a route for the internet gateway.
  • 0.0.0.0/0 which means let’s take anything from anywhere.
  • select internet gateway
  • save
  • now we have a way for our subnets to reach the internet.
• it’s time to create some subnets.
• these are default ones created with your default VPC
  • there’s exactly one for every availability zone within each region
  • my region is seoul, which has 4 public subnets.
• check the auto assign to Yes
  • if this is set to Yes, that means any EC2 instance launch in the subnet is going to get a public IP address.
  • Hence, it’s going to be considered a public subnet.
• a lot of companies wants to run on at least three availability zones for high availability.
  • because one goes out, if you have another one, what happens if two goes out.
  • so commonly create at least two additionals.
• we’re gonna make 3 subnets and 1 private subnet

• first of all, make subnet for A.

• this CIDR range is smaller than the one up here.
  • the number is larger, but from the perspective of how many IP addresses it allocates, there’s actually a fewer here.
  • you can set this as 16, it’s always goint to be less, I mean a higher number than 16.
• the auto sign is going to be set to No.
  • modify this and set it is considered a public subnet.

• make subnets for B and C and private A too.

• public A, B, C are already automatically asscociated with main route table by default.
• but for our private one, we’re not gonna wanting to really use the main route table there.
  • so we probably would want to
    create our own route table for our private subnets</b>.
• we don’t need the subnet to reach the internet.
• so just change the association here.

Words

• on the left hand side : 왼쪽에

The copyright of all material here is on this video https://www.youtube.com/watch?v=Ia-UEYYR44s
This post is just for studying AWS SAA.