codecentric / aws-example

AWS-Example

This repository is an introductory example to Infrastructure as Code (IAC) with AWS, Terraform and Ansible.

The example is the provisioning of an EC2 instance, hosting a simple html through an nginx.

Prerequisites

AWS Setup

AWS account

In order to get started, you need an AWS account. You can set a budget (Services > Billing > Budget > Create Budget) to make sure you won't have any unpleasant surprises. For this tutorial you will need at most a few dollars, so you could set up a budgt for around 10$.

IAM User

To be able to build up infrastructure in AWS from your own machine, you need an IAM user. Go to Services > IAM > Groups and create a new group that has the following access rights:

• AmazonEC2FullAccess
• IAMFullAccess
• AmazonS3FullAccess

Now create a new user within this group. Be cautious with your credentials!

On your own machine, create the file ~/.aws/credentials with that users access key and this structure:

[default]
aws_access_key_id=xxxxx
aws_secret_access_key=xxxxx

Keypair

To connect to a machine that you create in AWS, you need a keypair, with the private key on your machine and the public key in AWS. You can create a new keypair on your own machine by running ssh-keygen -t rsa in a shell.

Note the path to the private key and replace the terraform variable privateKeyPath in modules/Infrastructure/main.tf with your own.

Click on Key Pairs in your EC2 Dashboard and import your public key.

Local Machine Setup

Install the following on your machine (versions I used are indicated in brackets):

terraform     (0.10.5)
ansible       (2.3.2.0)
python2       (2.7.13)
pip2          (9.0.1)
pip2 install -U boto six ansible

Running the Example Code

Setup AWS Bucket for Terraform State

Navigate to modules/TerraformState and run terraform init, then terraform apply. This will create an AWS S3 bucket where you can remotely store your terraform state. This makes it easiest to work in a team. You will also see a new .terraform folder in this directory which holds amongst other things the terraform state for your newly created S3 bucket. Navigate to your S3 bucket to have a look.

Provision your Infrastructure

Navigate to modules/Infrastructure and run terraform init. This will create the terraform state in the above mentioned S3 bucket.

Now you can run terraform apply which will create a new security group and an EC2 instance.

Security Group

The security group is configured to allow ssh and http traffic to the instance and anything away from the instance.

EC2 Instance

The EC2 instance is setup with an ubuntu 16.04 as amazon machine image (ami).

The remote provisioner ensures that an ssh connection is established and python is installed; both are prerequisites for ansible.

The local provisioner runs the ansible playbook that you can find in modules/Provision, which installs and starts an nginx webserver and hosts a simple html.

Checking the Result

In the EC2 Dashboard you should now see 1 Running Instance and 2 Security Groups (yours in addition to the default VPC).

Clicking on Running Instances will list all EC2 instances. Copy the public IP from the rightmost column into a new browser tab and look at your new website!

Playground

There is a couple of things you could change now to get more comfortable with your infrastructure.

• Change the instance type to a smaller one e.g. t2.micro, or bigger one e.g. t2.large.
• Add more instances by increasing the count variable.
• Create a load balancer to handle all these instances.
• Create a custom network to your infrastructure and add your instance to a subnet in that new network.
• Add additional tasks to the ansible playbook to fit your needs.

Clean Up

Run terraform destroy in modules/Infrastructure to clean up your infrastructure and to avoid unneccessary cost.

To get rid of S3 bucket as well, set the lifecycle parameter prevent_destroy = false and run terraform destroy in modules/TerraformState.