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1suleyman
1suleyman

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💥 Terraform at Scale: What Happens When Your API Calls Hit the Limit

Hey everyone 👋

If you’ve been using Terraform to manage your cloud infrastructure — especially on AWS — there’s a challenge you’ll eventually face as your projects grow: API throttling.

When I first started with Terraform, everything felt smooth — until one day, running terraform plan on a big project slowed to a crawl and weird errors started popping up. The culprit? Too many API calls.

Let me break it down in simple terms 👇


🧸 Imagine Terraform Like a Warehouse Manager

Let’s say Terraform is managing a giant warehouse (your cloud infrastructure). Every time you run terraform plan, it walks through the entire building checking stock, condition, and layout — for every shelf.

Now imagine this warehouse grows to 10x its original size.

Same manager, same task… but way more walking, way more checks, and a limit to how many requests he can make per hour. That’s what Terraform does with API calls when refreshing your infrastructure state.


⚠️ What Is API Throttling (and Why Should You Care)?

Cloud providers like AWS place limits on how many API requests you can make in a short period. If you exceed that quota, your requests get throttled — delayed or outright blocked.

📌 Real AWS Examples:

  • EC2 DescribeInstances → Limited per second
  • IAM GetRole → Limited per minute
  • CloudWatch Logs → Throttled if overused

🧠 Think of It Like...

Customer support lines. You’re allowed 100 calls/hour. On the 101st call, you’re put on hold — or worse, your call drops.


💥 Terraform Makes A Lot of API Calls

Every time you run terraform plan, it:

  • Refreshes the state of every resource
  • Verifies what exists vs what needs to change
  • Sends multiple API requests per resource

If your project has:

  • 100+ resources
  • Multiple modules (VPC, subnets, NAT gateways, SGs)
  • High-frequency changes...

Then even a single plan or apply can hit the API limits — especially in production environments that are already busy.


🧪 Real-World Example: When Plans Became a Problem

I worked on a project that implemented CIS security hardening across multiple AWS accounts using Terraform. These policies involved hundreds of rules — all defined as code.

Running terraform plan on this setup led to:

  • 200+ resources being checked
  • Dozens of API calls per module
  • 🚨 Throttling that caused production slowdowns

We had to find solutions fast — and here's what worked 👇


🛠️ 3 Terraform Tricks to Reduce API Load

✅ 1. Split Projects into Smaller Modules

Instead of one massive Terraform project, break it down by service or purpose:

/vpc
/iam
/security-groups
/ec2
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Now each terraform plan only checks its own scope — way fewer API calls.

✅ 2. Use Resource Targeting (-target)

Apply one resource at a time:

terraform apply -target=aws_instance.web_server
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This limits the refresh and apply to just the targeted resource — much gentler on your API budget.

✅ 3. Disable State Refresh (-refresh=false)

If you know your state file is accurate, you can skip the refresh step entirely:

terraform plan -refresh=false
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⚠️ Warning: Only do this if you're sure nothing has changed manually. Otherwise, you risk applying outdated info.


🚀 Terraform Commands Recap

🛠️ Command 📉 API Load 🔍 What It Does
terraform plan High Refreshes all resources
terraform plan -refresh=false Low Skips refresh, faster but riskier
terraform apply -target=... Medium Targets specific resource(s) only

💬 Final Thoughts: Scale Smart with Terraform

Terraform is powerful — but with great power comes… API rate limits 😅

If you're managing large-scale infrastructure:

  • Expect throttling
  • Architect your Terraform workflow carefully
  • Use smaller modules, smart targeting, and refresh skipping strategically

Don’t let terraform plan be the thing that takes your prod down.


Are you dealing with large Terraform projects? Got a better strategy for managing API limits? I’d love to swap tips — connect with me on LinkedIn or drop a comment 💬☁️

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