DevOps Classroom Series – 21/May/2020

Terraform Template to Create AWS VPC

1. Create a folder ‘vpcinaws’
2. In this folder create a file called as main.tf (<anyname>.tf). This file main.tf will be our template in this example
3. Since we want to create vpc on AWS, lets see how to configure AWS Provider Refer Here
   • Provider syntax

   provider '<name>' {
       <arg1> = <value1>
       ..
       ..
       <argn> = <valuen>
   }
   

   • Navigate to Argument Reference
   • Connecting Terraform to your AWS Account (Authentication)
   • In this example we will be using static credentials and to create IAM user Refer Here
   • Make a note of access key id and secret
4. Since we need to create a vpc in mumbai note the region code ‘ap-south-1’
5. Add the following block to main.tf

provider "aws" {
    region      = "ap-south-1"
    access_key  = "<your access key>"
    secret_key  = "<your secret key>"
  
}

6. Resource Syntax

resource "<type of resource>" "<name of resource>" {
    <arg1> = <value1>
    ..
    ..
    <argn> = <valuen>
}

7. Now google for terraform <provider> <resource name> resource now in this case i would google with terraform aws vpc resource and open resource documentation and navigate to argument reference
8. After navigating to here and adding resource section to main.tf

provider "aws" {
    region      = "ap-south-1"
    access_key  = "<your access key>"
    secret_key  = "<your secret key>"
}
resource "aws_vpc" "myvpc" {
    cidr_block      = "10.10.0.0/16"

    tags            = {
        Name        = "from terraform"
    }
  
}

9. Basic Terraform Workflow
10. Now open terminal and cd in to the folder and execute the following

cd ./vpcinaws/
terraform --help

11. Initialize the terraform to download providers

terraform init

12. Lets validate our terraform template

terraform validate --help
terraform validate .

13. Lets apply to create the resources

terraform apply --help
terraform apply .

• Now navigate to AWS VPC to manually verify

• Now lets try to reexecute apply

• Now change the tag Name in UI and re execute apply, Terraform tries to set the state to what ever is written in template.

• Now we can delete this by executing

terraform destroy --help
terraform destroy .

• Experiment count with VPC

provider "aws" {
    region      = "ap-south-1"
    access_key  = "<your access key>"
    secret_key  = "<your secret key>"
}
resource "aws_vpc" "myvpc" {
    count           = 3
    cidr_block      = "10.10.0.0/16"

    tags            = {
        Name        = "My VPC ${count.index}"
    }

}

Terms in Terraform which we used in this Series

• Provider
• Resource
• Argument => input to the Providers/Resources
• init
• apply
• validate
• destroy
• count in resource => number of resources to be created.