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Get in CloudFormation; A Timeline learning IaC for AWS


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A big shoutout to Pluralsight for their free weekend, and James Millar for a great introductory course. For the longest time, I couldn't see how people found this easy, but this helped.

(Why did we make up so many programming languages that only work based upon the correct formatting of spaces and tabs? Readability is important, but when you're just beginning, how I learn, I'm interested in 'it works' first and 'it's pretty' second).


The (paid) project:

Create an Instance that has basic security rules from a security group it's in. The most difficult part was learning the tool and the formatting. This was much easier in Terraform (Now OpenTofu) for AWS, but this time we wanted to use CloudFormation.


The Numbers:

Resources Created: At least 11

  • VPC
  • MacOSImageID*
  • MacOSInstanceKeyName*
  • InternetGateway
  • PublicInternetRoute
  • VPCGatewayAttachment
  • PublicInternetRouteTable
  • PublicSubnet01
  • PublicSubnet01RouteTableAssociation
  • SecurityGroup
  • NetworkInterfaceAttachment

The Mac Instances were placed within later.



 TLDR? Check out the code on GitHub.

You can use a nifty GUI getup to drag and drop elements to create a JSON file;



It's not as easy at it seems, as I had to ask myself important questions:


What's the difference between a host and an instance?

Minutia; One's more expensive per hour.


Why does this throw an error?

Because YAML is picky about spacing.

This required me to make a Mac Virtual Machine. Only available in the East Virginia region through EC2; I ended up using a regular EC2 instance in its place for testing, so the client could upload the file and switch in their own Mac Instance.

You use !Ref to tie things to other elements. If I have an EC2 Instance, I'd use !Ref in the space where it asks about Firewalls to reference the one I have without hardcoding it in, very much like Variables in Terraform For Azure and AWS.


Create a KeyPair (Easy)
Place in A Firewall with rules about access (Hm.)

The Firewall part had the clearest documentation in AWS' CloudFormation section.

Type: AWS::NetworkFirewall::Firewall
  DeleteProtection: Boolean
  Description: String
  FirewallName: String
  FirewallPolicyArn: String
  FirewallPolicyChangeProtection: Boolean
  SubnetChangeProtection: Boolean
    - SubnetMapping
    - Tag
  VpcId: String
I found no page for the header type for integrating Key Pairs. The Key Pair parameter doesn't go where I thought, it goes under Parameters for the EC2 Instance.



    Type: AWS::EC2::Image::Id
    Default: ami-074f143fc810219ae

    Type: AWS::EC2::KeyPair::KeyName
    Default: macos

Turns out, lots of people haven't migrated to Firewalls in CF yet. Security Groups, at a basic level, get the job done for their purposes. At least I have a good start on using AWS Firewalls.

AWS can be touchy about putting certain resources in certain regions.

API: ec2:RunInstances Not authorized for images

showed up when I tried to push a sample stack - from AWS - and it didn't work in the Ohio region. Some are region limited - something I learned from a third-party video.

💡 Consider making Amazon-given samples accessible to all regions.

A lot of things became clear the more I learned -  ex. hitting Template and Edit in Designer when a stack failed to launch.

The fact that it doesn't check the fields of things that must be specified until the end is a real pain. To its credit, it will throw all of the errors at you if they relate to other network elements - If there are errors in the EC2 instance, those are separate from those in a Firewall. It's easy to read.

I didn't have a lot of the Properties under my AWS::EC2::Route section; Remember the documentation says a lot of them aren't required. And yet;

So is there another part of my template making it necessary? Such as 'Oh, you have part A, now you need part B so it all works'?

I was eventually lead down the path of circular dependencies; Shout out to the 2nd piece of useful documentation I've come across about AWS CloudFormation.


💡 I also got to use curl and AWS CLI. 


Once again, AWS Documentation was a little too high level for a beginner, so Cloud Academy came through with how to actually set it up after installation. 

At least 3 times on Twitter, I had to ask the general population if it was intended to be this unclear, and 3 times the AWS team apologized and told me to submit feedback.

I thought it was just me, but no, their documentation confuses many people.

To their credit, AWS did come through with the actual commands; Well done! I connected via the console and bungled setting up the credentials through 'aws configuration' line - Which turned out to be a very insecure method of securing an EC2 instance.

 Here's a better way that involves policies and IAMs.

Their course on Udemy is great, and thank you again to a LI connection for the gifted course!

There are quirks in the programming; Most of the time, I've found !Ref works. But when making a firewall, it preferred Fn::GetAtt [name,name].

After lots of trial, error, and help, I managed to push an instance and some buckets - I can even log into the instance!

The second part of the task was seeing about MDM systems being compatible with EC2 instances; The general consensus was yes.


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