Estimate infra costs when using Terraform

October 31, 2023

Infracost for Terraform code

Many companies use Terraform as a IaC standard. Though, every other company finds themselves in situation when their infrastructure grows really quick and they end up with huge bills. In this situation, there are many different approaches you can take One of them, is proactively understand and track the cloud spent

One of the best tools for this is an Infracost. It is becoming more of a standard for this kind of job. There are lots of integrations, super easy to get started, and provides good visualisation capabilities (for some extra fees)

Highlights & Features of Infracost

  • infracost CLI that allows to give you cost estimate in single command
  • Define your FinOps tagging policies here to communicate and enforce required tag keys/values in pull requests. This enables you to shift-left on your tagging practices and provide engineers with fast feedback loops vs asking them to clean up tagging issues post-deployment.
  • Post cost estimates in pull requests
  • infracost diff shows diff of monthly costs between current and planned state
  • Infracost Cloud with dashboard & integration with CI/CDs
  • Infracost supports over 1,000 Terraform resources
  • works with Terraform, Terragrunt , Cloudformation
  • Guardrails help you control costs by monitoring pull requests and triggering actions when thresholds are exceeded. You can define cost or percentage based thresholds, and setup email approvals or Slack notifications.
  • Integration with GIT (Github & Enterprise Cloud, Gitlab, Azure Repos, Bitbucket)
  • Infracost VS Code integration

Infracost Licence

Apache-2.0 license, SOC2 Type II certified , 9.7k stars on Gitbhub

Infracost Pricing

Infracost is open source , but also has a Cloud SaaS offering

"Infra Cost CI/CD" has free 1,000 runs per month, upgrade packs can be purchased (purchase now) Price per upgrade pack of 10K per month runs in Oct 2023 is $150.00 (excluding tax.)

"Infracost Cloud" costs $50 per seat . Seats are equal to authors of PRs. Atthe end of the month Infracost Cloud counts how many unique PR authors you have, and add any seats needed for Infracost Cloud users. If you have a monorepo with code different that TF, it only takes into account PRs related to Terraform code only

"Infracost Enterprise" Price not listed, but we would put a ballmark of 1-8% based on your Cloud bill and other similar Cloud pricing tools for Enterprise.

Enterprise discounts:

  • AWS Enterprise Discount Program (EDP)
  • Google Commitment Agreement
  • Azure Prepayment / Azure Monetary Commitment which are part of Azure Enterprise Agreements

Infracost Pricing documentation

Infracost Github

Infracost Documentation

Infracost Blog & Use cases

Install the Infracost

Install Infracost on macOS with brew
brew install infracost

infracost --version
Install Infracost on Linux/ Bash script via Curl
curl -fsSL | sh
Install Infracost on Windows
choco install infracost

infracost --version
Run Infracost in Docker (For CI or AMD images)

docker pull infracost/infracost:ci-latest

docker run --rm \
  -e INFRACOST_API_KEY=see_following_step_on_how_to_get_this \
  -v $PWD/:/code/ infracost/infracost:ci-latest breakdown --path /code/

Dockerised CLI is targetting CI systems, as well there is no ARM Docker Image yet On Mac M1 you will get following errors "no matching manifest for linux/arm64/v8". Check Infracost Gihub Issue: Build arm64 Docker image #2492

Using infracost CLI with Terraform code

When using free Cloud Pricing API, you need to get an API key via "infracost auth login" command

The API key after succesful auth is saved under <Home_DIR_OS_USER>.config/infracost/credentials.yml

infracost auth login

Provide a breakdown of cloud costs based on Terraform code

infracost breakdown --path=.

Example output :

Evaluating Terraform directory at .
  ✔ Downloading Terraform modules 
  ✔ Evaluating Terraform directory 
  ✔ Retrieving cloud prices to calculate costs 

Project: cloudtipss/Private-EKS-With-Bastion-Host

 Name                                                                                          Monthly Qty  Unit                    Monthly Cost 
 ├─ Instance usage (Linux/UNIX, on-demand, t3.small)                                                   730  hours                         $15.18 
 └─ root_block_device                                                                                                                            
    └─ Storage (general purpose SSD, gp2)                                                                8  GB                             $0.80 
 ├─ Data ingested                                                                        Monthly cost depends on usage: $0.50 per GB             
 ├─ Archival Storage                                                                     Monthly cost depends on usage: $0.03 per GB             
 └─ Insights queries data scanned                                                        Monthly cost depends on usage: $0.005 per GB            
 └─ EKS cluster                                                                                        730  hours                         $73.00 
 └─ module.eks.module.eks_managed_node_group["on_demand_1"].aws_launch_template.this[0]                                                          
    ├─ Instance usage (Linux/UNIX, on-demand, t3.small)                                                730  hours                         $15.18 
    └─ EC2 detailed monitoring                                                                           7  metrics                        $2.10 
 ├─ Customer master key                                                                                  1  months                         $1.00 
 ├─ Requests                                                                             Monthly cost depends on usage: $0.03 per 10k requests   
 ├─ ECC GenerateDataKeyPair requests                                                     Monthly cost depends on usage: $0.10 per 10k requests   
 └─ RSA GenerateDataKeyPair requests                                                     Monthly cost depends on usage: $0.10 per 10k requests   
 ├─ NAT gateway                                                                                        730  hours                         $32.85 
 └─ Data processed                                                                       Monthly cost depends on usage: $0.045 per GB            
 OVERALL TOTAL                                                                                                                           $140.12 
61 cloud resources were detected:6 were estimated, 4 of which include usage-based costs, see
∙ 55 were free, rerun with --show-skipped to see details

┃ Project                                            ┃ Monthly cost ┃
┃ cloudtipss/Private-EKS-With-Bastion-Host           ┃ $140         ┃