Day 63 - Terraform Variables 🔧

Hello, DevOps enthusiasts! Welcome to Day 63 of the #90DaysOfDevOpsChallenge. Today, we'll explore variables in Terraform. We'll see how they help manage configurations effectively. Let's dive in and get hands-on with some practical examples on AWS! 🌟

Understanding Terraform Variables 🧩

Variables in Terraform are essential for storing values such as instance names, configurations, and more. They help make your code modular and reusable.

Install Terraform:

sudo apt-get update
sudo apt-get install -y gnupg software-properties-common curl
curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -
sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main"
sudo apt-get update
sudo apt-get install terraform
terraform -version

Step 1: Creating Variables in Terraform 📜

1. Create a new file named variables.tf:

    touch variables.tf
   

   📁 File created!

2. Add the following variable definitions in variables.tf:

    variable "filename" {
      default = "/home/ubuntu/terraform-tutorials/terraform-variables/demo-var.txt"
    }
   
    variable "content" {
      default = "This is coming from a variable which was updated"
    }
   

   ✏️ Variables defined!

   

Step 2: Using Variables in main.tf 🌐

3. Create a new main.tf file if you don't have one already:

    touch main.tf
   

   📄 File created!

4. Add the following code in main.tf to use the variables:

    resource "local_file" "devops" {
      filename = var.filename
      content  = var.content
    }
   

   📜 Variables used in resource!

   

Data Types in Terraform 📚

Terraform supports various data types like Map, List, Set, and Object. Let's see some examples.

Step 3: Using Map Data Type 🗺️

5. Add a map variable to variables.tf:

    variable "file_contents" {
      type = map(string)
      default = {
        "statement1" = "this is cool"
        "statement2" = "this is cooler"
      }
    }
   

   🗺️ Map variable added!

Step 4: Using List, Set, and Object Data Types 📋

6. Add list, set, and object variables to variables.tf:

    variable "my_list" {
      type    = list(string)
      default = ["one", "two", "three"]
    }
   
    variable "my_set" {
      type    = set(string)
      default = ["apple", "banana", "cherry"]
    }
   
    variable "my_object" {
      type = object({
        name   = string
        age    = number
        active = bool
      })
      default = {
        name   = "John Doe"
        age    = 30
        active = true
      }
    }
   

   📋 Variables for list, set, and object added!

   

   

Step 5: Using these Variables in main.tf 📑

7. Access and print these variables in main.tf:

    output "list_output" {
      value = var.my_list
    }
   
    output "set_output" {
      value = var.my_set
    }
   
    output "object_output" {
      value = var.my_object
    }
   

   🔄 Variables accessed and outputs defined!

   

Step 6: Initialize and Apply the Configuration 💻

8. Initialize your Terraform configuration:

    terraform init
   

   🏁 Initialization complete!

   

9. Apply the Terraform configuration to see the outputs:

    terraform apply
   

   Review the execution plan and confirm by typing yes. ✔️

   

   

   

Step 7: Refreshing the State 🔄

10. Refresh the Terraform state:

    terraform refresh
    

    This reloads the variables and updates the state file. 🔄 State refreshed!

    

Summary 📚

Today, we've covered how to:

• Define and use variables in Terraform.

• Utilize different data types like map, list, set, and object.

• Initialize and apply Terraform configurations.

• Refresh Terraform state.

Keep practicing and happy learning! 🚀

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Feel free to reach out if you have any questions or run into any issues. See you tomorrow for another exciting day of the #90DaysOfDevOpsChallenge! 🌟