===== Terraform =====
Terraform is an open-source infrastructure as code software tool created by HashiCorp. It enables users to define and provision a datacenter infrastructure using a high-level configuration language known as Hashicorp Configuration Language (HCL), or optionally JSON. Terraform supports a number of cloud infrastructure providers such as Amazon Web Services, IBM Cloud (formerly Bluemix), Google Cloud Platform, DigitalOcean, Linode, Microsoft Azure, Oracle Cloud Infrastructure, OVH, or VMware vSphere as well as OpenNebula and OpenStack.\\
==== Provider Configuration ====
=== Generic Provider ===
//see also:// [[https://www.terraform.io/docs/configuration/providers.html|Providers - Configuration Language - Terraform by Hashicorp]]\\
\\
=== AWS ===
The Amazon Web Services (AWS) provider is used to interact with the many resources supported by AWS. The provider needs to be configured with the proper credentials before it can be used.\\
  # Configure the AWS Provider
  provider "aws" {
    version = "~> 2.0"
    region  = "us-east-1"
  }
  
  # Create a VPC
  resource "aws_vpc" "example" {
    cidr_block = "10.0.0.0/16"
  }
\\
== Static Credentials ==
You can provide static credentials by adding an ''access_key'' and ''secret_key'' in-line in the AWS provider block:
  provider "aws" {
    region     = "us-west-2"
    access_key = "my-access-key"
    secret_key = "my-secret-key"
  }
\\
== Environment Variables ==
You can also provide your credentials via the ''AWS_ACCESS_KEY_ID'' and ''AWS_SECRET_ACCESS_KEY'' environment variables, representing your AWS Access Key and AWS Secret Key, respectively. Note that setting your AWS credentials using either these (or legacy) environment variables will override the use of ''AWS_SHARED_CREDENTIALS_FILE'' and ''AWS_PROFILE''. The ''AWS_DEFAULT_REGION'' and ''AWS_SESSION_TOKEN'' environment variables are also used, if applicable:
  provider "aws" {}
To create the environment variables, enter into shell:
  $ export AWS_ACCESS_KEY_ID="anaccesskey"
  $ export AWS_SECRET_ACCESS_KEY="asecretkey"
  $ export AWS_DEFAULT_REGION="us-west-2"
  $ terraform plan
\\
== Shared Credentials File ==
You can use an AWS credentials file to specify your credentials. The default location is ''$HOME/.aws/credentials'' on Linux and OS X, or ''"%USERPROFILE%\.aws\credentials"'' for Windows users. If we fail to detect credentials inline, or in the environment, Terraform will check this location. You can optionally specify a different location in the configuration by providing the ''shared_credentials_file'' attribute, or in the environment with the ''AWS_SHARED_CREDENTIALS_FILE'' variable. This method also supports a profile configuration and matching ''AWS_PROFILE'' environment variable:
  provider "aws" {
    region                  = "us-west-2"
    shared_credentials_file = "/Users/tf_user/.aws/creds"
    profile                 = "customprofile"
  }
If specifying the profile through the ''AWS_PROFILE'' environment variable, you may also need to set ''AWS_SDK_LOAD_CONFIG'' to a truthy value (e.g. ''AWS_SDK_LOAD_CONFIG=1'') for advanced AWS client configurations, such as profiles that use the ''source_profile'' or ''role_arn'' configurations.
==== Adding User Data in Configs ====
To add a user data file into a startup/config script, first store your script in a server-accessible location, then create a file named ''userdata.txt'' using the following template:
  <powershell>
  C:\\Path\\To\\Your\\Launch\\Scripts\\InitializeInstance.ps1 -Schedule
  </powershell>
You can then launch the instance by specifying the text file containing pointers to your script(s):
  resource "aws_instance" "my-test-instance" {
    ami             = "${data.aws_ami.ec2-worker-initial-encrypted-ami.id}"
    instance_type   = "t2.micro"
  
    tags {
      Name = "my-test-instance"
    }
  
    user_data = "${file(userdata.txt)}"
  }
==== Selected Documentation ====
  - [[https://www.terraform.io/docs/providers/aws/index.html#argument-reference|Provider: AWS - Argument Reference]] - These arguments, along with the [[terraform#generic_provider|generic provider arguments]], are supported in the AWS Provider block
===== References =====
  - [[https://www.terraform.io/docs/providers/aws/index.html|Provider: AWS - Terraform by Hashicorp]]
  - [[wp>Terraform_(software)|Terraform]]