Day 10 — Top 10 Terraform Meta-Arguments with Examples

1. Introduction

What meta-arguments are (special arguments that modify the behavior of resources and modules).
Why they are important for clean, scalable infrastructure.

2. Top 10 Meta-Arguments with Examples

count – Create multiple instances of a resource.

 resource "aws_instance" "example" {
   count = 3
   ami           = "ami-123456"
   instance_type = "t2.micro"
 }

👉 Spins up 3 EC2 instances.

for_each – Iterate over a map or set.

 resource "aws_s3_bucket" "example" {
   for_each = toset(["app", "logs", "backup"])
   bucket   = "${each.key}-bucket-123"
 }

👉 Creates multiple buckets with unique names.

depends_on – Explicitly set dependencies.

 resource "aws_instance" "example" {
   ami           = "ami-123456"
   instance_type = "t2.micro"
   depends_on    = [aws_s3_bucket.example]
 }

👉 Ensures the EC2 is created after the bucket.

provider – Use multiple provider configurations.

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

 provider "aws" {
   alias  = "mumbai"
   region = "ap-south-1"
 }

 resource "aws_instance" "mumbai" {
   provider      = aws.mumbai
   ami           = "ami-123456"
   instance_type = "t2.micro"
 }

👉 Deploys in multiple regions.

lifecycle – Manage how Terraform handles changes.

 resource "aws_s3_bucket" "example" {
   bucket = "mybucket-123"

   lifecycle {
     prevent_destroy = true
   }
 }

👉 Prevents accidental deletion.

provisioner – Run scripts after resource creation.

 resource "aws_instance" "example" {
   ami           = "ami-123456"
   instance_type = "t2.micro"

   provisioner "local-exec" {
     command = "echo Instance created > instance.log"
   }
 }

👉 Executes a local script after instance creation.

connection – Define how Terraform connects to resources.

 resource "aws_instance" "example" {
   ami           = "ami-123456"
   instance_type = "t2.micro"

   connection {
     type     = "ssh"
     user     = "ec2-user"
     password = "example-pass"
     host     = self.public_ip
   }
 }

👉 Defines SSH connection for remote provisioning.

timeouts – Control how long Terraform waits.

 resource "aws_instance" "example" {
   ami           = "ami-123456"
   instance_type = "t2.micro"

   timeouts {
     create = "10m"
     delete = "5m"
   }
 }

👉 Useful for slow services.

tags (special for AWS) – Assign metadata.

 resource "aws_instance" "example" {
   ami           = "ami-123456"
   instance_type = "t2.micro"
   tags = {
     Name = "ExampleInstance"
     Env  = "Dev"
   }
 }

👉 Helps in cost tracking & resource identification.

source (in modules) – Define where the module comes from.

module "vpc" {
  source = "terraform-aws-modules/vpc/aws"
  name   = "my-vpc"
  cidr   = "10.0.0.0/16"
}

👉 Allows reusability with community or local modules.

3. Best Practices

Use for_each instead of count when dealing with named resources.
Always tag resources for better management.
Use depends_on sparingly (Terraform usually handles dependencies).
Avoid provisioners unless absolutely necessary.

4. Conclusion

Meta-arguments supercharge your Terraform.
They make code scalable, reusable, and predictable.

Follow my journey

GitHub (learning repo): https://github.com/abdulraheem381/terraform-learning-journey
X / Twitter: https://x.com/Abdulraheem183
Hashnode series: https://abdulraheem.hashnode.dev/series/terraform-with-aws