> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Meta Arguments amp Count and for each

> This guide explains provisioning multiple EC2 instances using `count` and `for_each` meta-arguments in OpenTofu, highlighting their differences in indexing and lifecycle behavior.

In this guide, you’ll learn how to provision multiple EC2 instances with the `count` and `for_each` meta-arguments in OpenTofu. Both approaches let you duplicate a single resource block, but differ in indexing and lifecycle behavior.

| Meta-Argument | Key Characteristic                     | Best Use Case                                |
| ------------- | -------------------------------------- | -------------------------------------------- |
| count         | Integer-based, zero-indexed            | Create a fixed number of identical resources |
| for\_each     | Key-based, uses a set or map of values | Stable addressing of dynamic or named items  |

***

## 1. Using `count`

The `count` meta-argument accepts an integer and creates that many instances of a resource.

```hcl theme={null}
resource "aws_instance" "web" {
  ami           = var.ami
  instance_type = var.instance_type
  count         = 3
}

variable "ami" {
  default = "ami-06178cf087598769c"
}

variable "instance_type" {
  default = "m5.large"
}
```

Run:

```bash theme={null}
tofu apply
```

Then verify:

```bash theme={null}
tofu state list
# aws_instance.web[0]
# aws_instance.web[1]
# aws_instance.web[2]
```

### Dynamic `count` with `length()`

Instead of hardcoding an integer, drive `count` from a list:

```hcl theme={null}
variable "webservers" {
  type    = list(string)
  default = ["web1", "web2", "web3"]
}

resource "aws_instance" "web" {
  ami           = var.ami
  instance_type = var.instance_type
  count         = length(var.webservers)

  tags = {
    Name = var.webservers[count.index]
  }
}

variable "ami" {
  default = "ami-06178cf087598769c"
}

variable "instance_type" {
  default = "m5.large"
}
```

Here, each instance tag is assigned by its `count.index`:

* `count.index = 0` → `Name = "web1"`
* `count.index = 1` → `Name = "web2"`
* `count.index = 2` → `Name = "web3"`

<Callout icon="triangle-alert" color="#FF6B6B">
  Removing or reordering items in the `webservers` list causes all subsequent resources to be reindexed. This can lead to unintended in-place updates instead of only removing the orphaned resource.
</Callout>

Example plan when deleting `"web1"`:

```plaintext theme={null}
# aws_instance.web[0] will be updated (web1 → web2)
# aws_instance.web[1] will be updated (web2 → web3)
# aws_instance.web[2] will be destroyed (web3)
```

***

## 2. Using `for_each`

The `for_each` meta-argument uses a set or map, giving each resource a stable key based on its value.

```hcl theme={null}
variable "webservers" {
  type    = set(string)
  default = ["web1", "web2", "web3"]
}

resource "aws_instance" "web" {
  ami           = var.ami
  instance_type = var.instance_type
  for_each      = var.webservers

  tags = {
    Name = each.value
  }
}
```

Run and list state:

```bash theme={null}
tofu apply
tofu state list
# aws_instance.web["web1"]
# aws_instance.web["web2"]
# aws_instance.web["web3"]
```

If you remove `"web1"` from the set and run `tofu plan`, only that resource is destroyed:

```plaintext theme={null}
# aws_instance.web["web1"] will be destroyed
Plan: 0 to add, 0 to change, 1 to destroy.
```

This ensures stable resource addressing and prevents unnecessary updates.

***

## Links and References

* [OpenTofu Documentation](https://docs.opentofu.org)
* [AWS EC2 Instance Resource](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance)
* [Terraform `count` Meta-Argument](https://developer.hashicorp.com/terraform/meta-arguments/count)
* [Terraform `for_each` Meta-Argument](https://developer.hashicorp.com/terraform/meta-arguments/for_each)

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