> ## 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.
# Using the for each Meta Argument
> Explains Terraform's for_each meta-argument for creating uniquely configured resources, how it differs from count, usage of each.key and each.value, and addressing instances by key.
In this lesson you'll learn how to use Terraform's `for_each` meta-argument to create multiple, uniquely configured resources from a single resource block. `for_each` is a more flexible alternative to `count` when you need per-resource uniqueness rather than many identical instances.
Why use `for_each` (versus `count`)
* `for_each` iterates over a map or set, allowing unique configuration per instance.
* Each instance receives a stable key (the map key or set element) instead of an index. This stability reduces accidental recreation of unrelated resources when items are added or removed.
* Use `for_each` when resources need different names, sizes, tags, networks, or other unique attributes.
* Inside the resource block you can reference `each.key` and `each.value` to access the current item.
Example: map of VM names to sizes
```hcl theme={null}
variable "vms" {
type = map(string)
default = {
"vm1" = "Standard_D2s_v3"
"vm2" = "Standard_D4s_v3"
"vm3" = "Standard_B2ms"
}
}
resource "azurerm_virtual_machine" "example" {
for_each = var.vms
name = each.key
location = "East US"
resource_group_name = "my-resource-group"
vm_size = each.value
os_profile {
computer_name = each.key
admin_username = "adminuser"
}
# Additional required blocks (networking, storage, etc.) omitted for brevity.
}
```
Because `var.vms` contains three key/value pairs, Terraform creates three VMs: `vm1`, `vm2`, and `vm3`, each with its configured size.
Referencing resources created with `for_each`
* Address an individual instance by its key in square brackets:
* `azurerm_virtual_machine.example["vm1"]`
* `azurerm_virtual_machine.example["vm2"]`
* `azurerm_virtual_machine.example["vm3"]`
* Use these keyed references when wiring resources together (for example, passing an instance ID or IP to another resource).
Using `each.key` and `each.value` inside the block
* `each.key` is the map key (here, the VM name).
* `each.value` is the map value (here, the VM size).
* You can reference `each.key`/`each.value` multiple times to configure name, tags, hostnames, and more.
* Combine them in interpolations. For example, to add a suffix to the computer name:
```hcl theme={null}
os_profile {
computer_name = "${each.key}-web"
admin_username = "adminuser"
}
```
Use cases and recommendations
* Prefer `for_each` when instances require distinct attributes or when you want stable addressing that won’t shift as you add or remove items.
* `count` is still useful when creating many identical resources where uniqueness is not needed.
* Map values can be primitive (strings, numbers) or nested objects to carry richer per-resource configuration (regions, tags, disk sizes, network IDs, etc.).
Comparison: `for_each` vs `count`
| Feature | `for_each` | `count` |
| ----------------- | ------------------------------------------- | ----------------------------------- |
| Iterates over | `map` or `set` | integer range |
| Stable addressing | Yes — keyed by map/set element (`each.key`) | No — indexed by position (`0..n-1`) |
| Best for | Resources with unique attributes | Repeated identical resources |
| Example | `for_each = var.vms` | `count = var.instance_count` |
Prefer `for_each` when your instances have unique attributes or when you want stable instance addressing that won't shift as items are added or removed.
When converting existing resources from `count` to `for_each` (or vice versa), resource addresses change. This can cause Terraform to plan to recreate resources unless you import or manipulate state appropriately. Always review the plan and consider state migration steps.
Links and references
* [Terraform: for\_each Meta-Argument](https://www.terraform.io/docs/language/meta-arguments/for_each.html)
* [Terraform: count Meta-Argument](https://www.terraform.io/docs/language/meta-arguments/count.html)
That covers the `for_each` meta-argument and how it compares to `count`. Use `for_each` to keep your configuration DRY while enabling per-resource uniqueness and stable addressing.