Terraform to Manage Infrastructure In AWS

Now that terraform is installed, let’s create a test project.

mkdir projects
cd projects

Create Terraform main configuration file.

touch main.tf

I’m doing a Test with AWS Provider but you can use other Providers for your projects. My terraform configuration provider section is as below.

$ vim main.tf
# Provider
 provider "aws" {
   access_key = ""
   secret_key = ""
   region = "us-west-1"
 }

Paste your AWS Access Key and Secret Key inside the access_key and secret_keysections respectively. You can also configure your AWS access credentials with AWS CLI tool.

When done, run terraform init to initialize a Terraform working directory.

$ terraform init
Initializing the backend...

Initializing provider plugins...
- Finding latest version of hashicorp/aws...
- Installing hashicorp/aws v4.51.0...
- Installed hashicorp/aws v4.51.0 (signed by HashiCorp)

Terraform has created a lock file .terraform.lock.hcl to record the provider
selections it made above. Include this file in your version control repository
so that Terraform can guarantee to make the same selections by default when
you run "terraform init" in the future.

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 provider configured to .terraform directory.

Let’s now add resource section to create AWS VPC and Subnet resources by editing the main.tf file.

# Provider
 provider "aws" {
   access_key = ""
   secret_key = ""
   region = ""
 }

# Retrieve the AZ where we want to create network resources
data "aws_availability_zones" "available" {}

# VPC Resource
resource "aws_vpc" "main" {
  cidr_block = "10.11.0.0/16"
  enable_dns_support = true
  enable_dns_hostnames = true
  tags {
    Name = "Test-VPC"
  }
  tags {
    Environment = "Test"
  }
}

# AWS subnet resource
resource "aws_subnet" "test" {
 vpc_id = "${aws_vpc.main.id}"
 cidr_block = "10.11.1.0/24"
 availability_zone = "${data.aws_availability_zones.available.names[0]}"
 map_public_ip_on_launch = "false"
 tags {
   Name = "Test_subnet1"
 }
}

Save the file after adding resource definitions and setting AWS variables then generate and show an execution plan.

$ terraform plan

Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.

data.aws_availability_zones.available: Refreshing state...

------------------------------------------------------------------------

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  + aws_subnet.test
      id:                               <computed>
      arn:                              <computed>
      assign_ipv6_address_on_creation:  "false"
      availability_zone:                "us-east-1a"
      availability_zone_id:             <computed>
      cidr_block:                       "10.11.1.0/24"
      ipv6_cidr_block:                  <computed>
      ipv6_cidr_block_association_id:   <computed>
      map_public_ip_on_launch:          "false"
      owner_id:                         <computed>
      tags.%:                           "1"
      tags.Name:                        "Test_subnet1"
      vpc_id:                           "${aws_vpc.main.id}"

  + aws_vpc.main
      id:                               <computed>
      arn:                              <computed>
      assign_generated_ipv6_cidr_block: "false"
      cidr_block:                       "10.11.0.0/16"
      default_network_acl_id:           <computed>
      default_route_table_id:           <computed>
      default_security_group_id:        <computed>
      dhcp_options_id:                  <computed>
      enable_classiclink:               <computed>
      enable_classiclink_dns_support:   <computed>
      enable_dns_hostnames:             "true"
      enable_dns_support:               "true"
      instance_tenancy:                 "default"
      ipv6_association_id:              <computed>
      ipv6_cidr_block:                  <computed>
      main_route_table_id:              <computed>
      owner_id:                         <computed>
      tags.%:                           "2"
      tags.Environment:                 "Test"
      tags.Name:                        "Test-VPC"


Plan: 2 to add, 0 to change, 0 to destroy.

------------------------------------------------------------------------

Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.

Finally build your Infrastructure with Terraform using terraform apply.

$ terraform apply

data.aws_availability_zones.available: Refreshing state...

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  + aws_subnet.test
      id:                               <computed>
      arn:                              <computed>
      assign_ipv6_address_on_creation:  "false"
      availability_zone:                "us-east-1a"
      availability_zone_id:             <computed>
      cidr_block:                       "10.11.1.0/24"
      ipv6_cidr_block:                  <computed>
      ipv6_cidr_block_association_id:   <computed>
      map_public_ip_on_launch:          "false"
      owner_id:                         <computed>
      tags.%:                           "1"
      tags.Name:                        "Test_subnet1"
      vpc_id:                           "${aws_vpc.main.id}"
...........................

Confirm changes to be made and type “yes” to initiate modifications.

Plan: 2 to add, 0 to change, 0 to destroy.
Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.
Enter a value: yes

A successful terraform run should print success message at the end.

Terraform state is saved to ./terraform.tfstate but the backend can be changed. You can confirm Infrastructure changes from AWS console.