aws-caascad-roles

This repository contains the definition of AWS IAM roles to create in AWS accounts managed by Caascad.

Currently the roles must be provisioned with terraform.

Terraform

The code is located in the ./terraform directory.

You can apply this code directly or you can use it as a terraform module in your own provisioning.

Installing terraform

The code is compatible with terraform 0.12.X series. You can find pre-built binaries of terraform here or you can install it using a package manager (depending of your system).

Terraform state

terraform manage a state file which track the different resources that you have created with terraform.

By default the state file is stored locally (local backend).

Multiple users can't manage the same terraform configuration if they don't share the state between them.

If you need to share the state file between multiple users you need to configure explicitely some remote backend.

You can add a file describing the backend you want to use in the ./terraform directory (for example in a file named override.tf).

Initialize terraform

Once you have installed terraform and configured a backend, go inside the terraform directory and run:

$ cd terraform
$ terraform init

Initializing the backend...

Initializing provider plugins...
- Checking for available provider plugins...
- Downloading plugin for provider "aws" (hashicorp/aws) 3.19.0...

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.

terraform will automatically download the AWS provider.

AWS credentials

To apply or plan the terraform configuration you need to provide AWS credentials to the AWS terraform provider.

Multiple options are available to do this. See the documentation of the AWS provider for more information.

We describe below two simple methods for providing AWS credentials to terraform.

The credentials you provide must have rights to create roles, policies in AWS IAM.

Environment variables

You can simply expose AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY environment variables and the terraform AWS provider will use them automatically.

AWS credentials file

If you already have an aws credentials file you can instruct terraform to use it.

In your override.tf file you can add:

provider aws {
    region  = "eu-west-3"
    profile = "<profile_name>"
}

Where <profile_name> is the name of some profile in your aws credentials file.

By default terraform will look at $HOME/.aws/credentials or "%USERPROFILE%\.aws\credentials" to find the credentials file.

Configuring inputs

This terraform configuration needs only one input:

• caascad_operator_trusted_arn: some IAM ARN will be be provided to you by Caascad

Once you have received the ARN from the Caascad team create a file named terraform.tfvars in the ./terraform directory with the following content:

caascad_operator_trusted_arn = "<ARN>"

Where <ARN> is the AWS IAM ARN provided by the Caascad team.

Planning terraform changes

Before trying to apply the configuration you can run a plan that will show you what will be provisioned on your AWS account:

$ terraform plan
...

If all goes well you can run apply:

$ terraform apply
...

After the apply command is complete you should see some outputs.

You need to communicate back to the Caascad team the value of the caascad_operator_role_arn output.