My first touch to Terraform and AWS

I decided to turn a new leaf on my professional development and try to learn AWS (Amazon Web Services). To this day, I have been quite anti-cloud but now I have to admit that cloud services like AWS may have their use. At least the potential employers require some kind of prior knowledge on at least one of the well-known cloud providers.

I have tried AWS before, but, to be honest, I had a hard time grasping the concepts and the confusing web console at the same time. Now I am going to utilize Terraform and AWS-cli to use AWS only from command line and code. No more web consoles!!! Feels so good already!

Installing Terraform

For whatever reason, Terraform is not available from the Fedora's repositories. I would prefer installing it from the repos. Then I would be (relatively) sure that it is build from the source.

However, installing Terraform is possible only by downloading a zip and unzipping the binary from there.

Setting up aws-cli

When spinning servers up with Terraform, it obviously needs a permission to access your AWS account. This is easiest done with aws-cli.

Install aws-cli with pip3:

pip3 install awscli --user # Assuming user-installation just to be sure :)

Then, follow this guide to set up aws-cli.

Terraforming

I then proceeded to follow the quick-start guide from Terraform. I did not want to use the us-east-1 region, which made the ami change. Ami stands for Amazon Machine Image. The ami changes based on the image (of course) and region and stuff like that. I didn't find a way to get the ami from the Amazon AMI marketplace. I then resorted to search-engines to find a way to programmically find out the right AMI. I wanted to use CentOS 7(link!), just because I am using Fedora on my laptop and my server experience is very Ubuntu-based. CentOS has a wiki article on how to get started with CentOS on AWS. I picked the product-code for later use.

The code

I ended up combining the Getting Started from Terraform and Mark Burke's wonderful article Get the latest AWS AMI IDs with terraform. Here's what the result looked like:

provider "aws" {
  profile = "default"
  region  = "eu-central-1"
}

data "aws_ami" "centos7" {
  most_recent = true
  owners = ["aws-marketplace"]

  filter {
    name = "product-code"
    values = ["aw0evgkw8e5c1q413zgy5pjce"]
  }
}

resource "aws_instance" "example" {
  ami     = "${data.aws_ami.centos7.id}"
  instance_type = "t2.nano"
}

I find the terraform DSL (domain specific language) syntax very nice. I think that in the above example, the code explains itself quite well. "Use provider aws with this profile and region. Then find the aws_ami of the product-code, which is CentOS 7. Then spin up an instance with the ami." Remember, that Terraform does not quite behave like code, since the data part is computed with terraform plan and only after that terraform apply works to find the ami for the resource.

I checked the AWS web console (https://eu-central-1.console.aws.amazon.com/ec2/v2/) and the instance was there! WOW!!!! This is quite cool. Remember to destory it if you don't need it. It is easily done using terraform destroy.

Conclusion

I didn't really test the AWS in any way. However, I can say with confidence, that using Terraform is quite easy to grasp and the aws-cli is a handy tool. I will probably try to do more of stuff like this in the future.