# Day 69 - Meta-Arguments in Terraform

Meta-arguments in Terraform are special configuration settings that can be applied to resources and modules. They provide additional functionality and control over how resources are created and managed. Meta-arguments enable you to customize resource behavior, handle resource dependencies, and iterate over sets or maps to create multiple instances.

Here are some commonly used meta-arguments in Terraform:

1. `count`: The `count` meta-argument allows you to create multiple instances of a resource based on a numeric value. It takes an integer value and generates a specified number of resource instances. It is useful when you need to create multiple similar resources, such as multiple EC2 instances or multiple subnets.
    

For example :  
  
create a terraform file using below code :

```bash
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.16"
    }
  }
  required_version = ">= 1.2.0"
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "server" {
  count         = 4
  ami           = "ami-053b0d53c279acc90"
  instance_type = "t2.micro"

  tags = {
    Name = "Server ${count.index}"
  }
}
```

In this code , the `count` meta-argument is used to create four instances of an AWS EC2 server. The `count.index` interpolation function is used within the `tags` block to assign a unique name to each instance based on the index.

Then run terraform init , terraform plan , terraform apply .

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1688418900685/00c0740b-5ab0-4601-95ed-3aea985635f9.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1688418935002/a5f609eb-ac8e-44d7-94c0-ebb779d88474.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1688418965385/d2b4a488-223d-414d-b3ec-24cf2271e5fe.png align="center")

it will create 4 instances.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1688419209383/f952690b-bc0c-490b-9ec3-d48b2458f1d7.png align="center")

1. `for_each`: The `for_each` meta-argument allows you to create multiple instances of a resource based on a set or map of values. It iterates over each element in the set or map and creates a separate resource instance for each element. It is handy when you want to dynamically create resources based on a set of configurations or when you need to manage resources individually.
    
    ```bash
    terraform {
      required_providers {
        aws = {
          source  = "hashicorp/aws"
          version = "~> 4.16"
        }
      }
      required_version = ">= 1.2.0"
    }
    
    provider "aws" {
      region = "us-east-1"
    }
    
    locals {
      ami_ids = toset([
        "ami-053b0d53c279acc90",
        "ami-06b09bfacae1453cb",
      ])
    }
    
    resource "aws_instance" "server" {
      for_each = local.ami_ids
    
      ami           = each.key
      instance_type = "t2.micro"
    
      tags = {
        Name = "Server ${each.key}"
      }
    }
    ```
    
    In this code snippet, the `for_each` meta-argument is used along with a local variable `ami_ids`. The `ami_ids` local variable is defined as a set of AMI IDs. The `for_each` block iterates over each AMI ID in the set and creates an AWS EC2 server instance for each AMI ID. The `each.key` represents the current AMI ID being iterated.
    

Then run terraform init , terraform plan , terraform apply . It will create 2 instances.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1688419511370/d689d8f0-8521-4df8-8f4e-d640ccea5fef.png align="center")

That was all for today. if you have any queries/suggestions please write in comment. See you another day with another challenge.