Processing Multiple Resources with the Terraform Count Argument

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The Terraform Count Argument is an ingenious tool that tackles the problem of computing multiple resources. It manages to do so in a way that uses no external dependencies, but also requires no compilation or unused components-only three lines of code. This example shows how using dataflow programming can be beneficial for complex software with many moving parts in terms of execution time and memory usage. To identify the problem, you should be using a 5 whys template that can help you identify what specific parts of a process are problematic.

The “terraform count conditional” is a command-line tool that allows users to process multiple resources with the Terraform Count Argument. The syntax for using the “terraform count conditional” is as follows:

Processing Multiple Resources with the Terraform Count Argument

The AWS Management Console allows you to create several resources of the same kind in one go, but how can you automate the process? The Terraform count parameter may be really useful!

In this article, you’ll learn how to use Terraform count to construct and execute a Terraform configuration to generate numerous EC2 instances in an AWS account.

Prerequisites

This lesson includes step-by-step instructions. If you want to join in, make sure you have the following items:

  • Terraform — This lesson will utilize Terraform v1.0.8 on Ubuntu 18.04.5 LTS, however Terraform should function on any operating system.

How to Install Terraform on Windows is a related topic.

  • An editor for coding — Any text editor will do, although one that understands the HCL Terraform language is preferable. Visual Studio (VS) Code is a good place to start.

Constructing a Terraform Setup

In a DevOps environment, you’ll most likely be working on a number of projects that include creating several resources of the same kind. Multiple EC2 instances, AWS S3 buckets, or Lambda functions may be used as these resources. Isn’t this a time-consuming procedure?

To automate the process of establishing many instances, create a Terraform configuration and set a Terraform count.

1. Run the commands below in your terminal to create a folder in your home directory and change the working directory to it.

The folder is entitled terraform-count-demo in this tutorial and is located in your home directory, but it may be named whatever you choose. Your Terraform configuration files are kept in this folder.

cd /terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo/

2. Open your preferred code editor and put the settings below into it. Save the configuration as main.tf in the /terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo/terraform-count-demo

Terraform makes use of a variety of configuration files. Each file is written in plain text or JSON format, with a name convention of.tf or.tfjson.

You may use the main.tf file to create four identical AWS EC2 instances, each with the same AMI and instance type defined as variables. The values for these variables are specified in a separate file called terraform.tfvars, which you’ll create later in this section.

The Amazon EC2 console is where you’ll locate Linux AMIs.

“aws instance” “my-machine” resource ## # Count = 4 # Creates four identical aws ec2 instances ami = var.ami instance type = var.instance type # tags = # ami = var.ami instance type = var.instance type # tags = # ami = var.ami instance type = var.instance type # tags = # ami = var.ami instance type = var.in You may use count.index to launch a resource # that starts with the unique index number 0 and corresponds to this instance. id = “my-machine-$count.index” id = “my-machine-$count.index” id = “my-machine-$count.index”

3. Now, within the /terraform-count-demo directory, create a new file called vars.tf and copy/paste the text below into it. The vars.tf file is a Terraform variables file that includes all of the variables referenced in the configuration file.

It is possible to include all configuration settings in a single configuration file. Breaking the logic and variables into distinct files is far more preferred to keep things clean and for developers and administrators.

# ami variable “ami” variable “ami” variable “ami” variable “ami” variable “ami” variable “ami” variable “ami” variable “ami” var type = string var type = string var type = string var type = string # Creating a Variable for the instance type variable “instance type” # Creating a Variable for the instance type variable “instance type” var type = string var type = string var type = string var type = string

4. Inside the /terraform-count-demo directory, create a new file named provider.tf and paste the code below into it. The AWS provider is defined in the provider.tf file, which allows Terraform to connect to the appropriate cloud services.

Getting Started with the Terraform AWS Provider is a related article.

The code below generates resources in the us-east-2 region using the AWS provider aws.

region = “us-east-2” provider “aws”

5. In the /terraform-count-demo directory, make one last file. Create a new file called terraform.tfvars and put the code below into it. Terraform utilizes the values in the terraform.tfvars file to replace variable references in configuration files.

instance type = “t2.micro” ami = “ami-0742a572c2ce45ebf”

6. Finally, run the tree command to ensure that the terraform-count-demo folder has all of the essential files.

terraform-count-demo tree

Verifying the Existence of Required Files Verifying the Existence of Required Files

Terraform is being used to create many AWS EC2 instances.

It’s time to start Terraform and launch four AWS EC2 instances now that you have the Terraform configuration file and variables files ready to go!

Terraform normally employs a three-stage process to provide a Terraform configuration: terraform init, terraform plan, and terraform apply.

To build an AWS ec2 instance, use the instructions below to get to the terraform-count-demo directory.

Related: [Step-by-Step] Creating Your First EKS Cluster with Terraform

# Open the terraform-count-demo directory in your browser. terraform-count-demo on cd # Terraform init # ensures the syntax of your configuration is accurate and provides an overview of which resources will be provided in your infrastructure. # of terraform plans Terraform apply provision/build AWS EC2 instances

Take note of the IDs in the Terraform output. You’ll need these IDs in the following step to link the resources you’ve built.

Creating Amazon EC2 Instances Creating Amazon EC2 Instances

AWS EC2 Instances Verification

You should have produced all of the Terraform-launched EC2 instances by now. However, carefully check in the AWS Management Console to see whether all of the EC2 instances exist.

Log in to the AWS Management Console using your preferred web browser. Now, go to the top of the page and type in ‘EC2’, then click the EC2 menu option, as seen below.

Getting started with an EC2 console. Getting started with an EC2 console.

On the EC2 page, you’ll see all the four EC2 instances you created. Verify that all IDs are the same ones that Terraform returned earlier under the “Terraform is being used to create many AWS EC2 instances.” section.

In the AWS interface, I'm checking all of the instances. In the AWS interface, I’m checking all of the instances.

Conclusion

You learnt how to utilize Terraform count in a Terraform configuration to launch or generate numerous resources at the same time in this article. Take everything you’ve learnt and apply it to managing your whole infrastructure using Terraform!

Frequently Asked Questions

Can we use for each and count together in Terraform?

A: Yes, you can use for each and count together in Terraform.

How do I run multiple instances with Terraform?

A: Terraform can be run in multiple instances. In the terraform directory, simply create a new .env file for each additional instance using the name of that instance as part of its path to help identify it from others.

How do you create multiple resources in Terraform?

A: Terraform requires a single file to define each resource. From the command line, you can use terraform init with an appropriate template to create your projects and their associated files.

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