Infracost.io Configuration

‍Introduction

Infracost is an open-source fin-ops tool that helps DevOps and developers continuously reduce their cloud costs.

Infracost integrates with terraform (Infrastructure-as-a-code tool) to provide the breakdown of cost and difference in cost for any pull request that DevOps/Developers raised with shift-left approach.

Infracost empowers to discuss costs before the actual resources are created, not after the resources are created.

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Getting Started

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Installation

1. Install Infracost

Assuming Terraform is already installed, get the latest Infracost release on mac:

brew install infracost

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2. Get API key

infracost register

The key is saved in ~/.config/infracost/credentials.yml .

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3. Run it

Run Infracost using our example Terraform project to see how it works:

git clone git@github.com:org/terraform.git

cd kong-terraform

# Get breakdown of cost for one of the env

infracost breakdown –path /dev/

# Show diff of monthly costs, edit the yaml file and re-run to compare costs infracost diff –path /dev/ –usage-file /dev/infracost-usage.yml

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Advanced usage

The following advanced usage methods can be used in addition to the usage methods mentioned above.

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Using Terraform plan file

Infracost can be run against a Terraform plan file.

cd /dev/

terraform init

terraform plan -out tfplan.binary

infracost breakdown –path tfplan.binary

infracost diff –path tfplan.binary

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Using Terraform state

The infracost breakdown command has a –terraform-use-state flag that is useful if you want to see the cost breakdown of the current Terraform state. This implies that you have already run Terraform apply .

infracost breakdown –path /dev/ –terraform-use-state

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Using Terraform state JSON file

The infracost breakdown command can be run against a Terraform state JSON file. This implies that you have already run Terraform apply , thus no cloud creds or –terraform-plan-flags is needed.

cd /dev/

terraform show -json > tfstate.json

infracost breakdown –path tfstate.json

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Generate reports

The infracost breakdown command has a –format json|table|html flag that can be used to change the output format. The JSON option can be used to generate files from individual projects that can then be consumed by the infracost output command to generate a combined report. The output command has a –format json|diff|table|html flag that sets the report format.

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Usage

Run infracost output –help to see the available options. Example usage:

infracost breakdown –path /dev/ –format json > project1.json infracost breakdown –path /stage/ –format json > project2.json infracost output –path project*.json –format html > report.html

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/94b48619-c82d-4a45-a9f4-350c0f59f1a0/report.html

Config file

An Infracost config file can be created in each of your Terraform project repos to specify how Infracost should be run.

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1. Create an infracost.yml file in each of your Terraform project repos. Each project can have the parameters mentioned in the table below:

version: 0.1

projects:

– path: /dev/tfplan.json

usage_file:/dev/infracost-usage.yml

– path: /test/tfplan.json

usage_file: /test/infracost-usage.yml

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2. Pass the file to the infracost breakdown or infracost diff using the -config-file option.

infracost breakdown –config-file infracost.yml

infracost diff –config-file infracost.yml

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Usage-based resources

Infracost distinguishes the price of a resource from its cost. For example, an EC2 instance might be priced at $0.02 per hour, and if run for 100 hours (its usage), it’ll cost $2. Supported resources in Infracost will always show prices, but if a resource has a usage-based cost component, we can’t show its cost as we don’t know how much it’ll be used. For example, an AWS Lambda resource shows no monthly costs for requests and duration:

Name Quantity Unit Monthly Cost aws_lambda_function.hi

├─ Requests Cost depends on usage: $0.20 per 1M requests

└─ Duration Cost depends on usage: $0.0000166667 per GB-seconds

PROJECT TOTAL $0.00

Infracost usage file

Infracost solves the above problem by enabling you to describe usage estimates in a file called infracost-usage.yml , which can be passed to Infracost using the –usage-file option so it can calculate costs. An infracost-usage.yml file with Lambda function usage estimates:

version: 0.1

resource_usage:

aws_lambda_function.hi:

monthly_requests: 100000000 # Monthly requests to the Lambda function.

request_duration_ms: 250 # Average duration of each request in milliseconds.

Running infracost breakdown –config-file infracost.yml –usage-file=infracost-usage.yml now shows monthly cost estimates:

Name Quantity Unit Monthly Cost

aws_lambda_function.hi

├─ Requests 100 1M requests $20.00

└─ Duration 12,500,000 GB-seconds $208.33

PROJECT TOTAL $228.33

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CI/CD Integration

Use our to automatically add pull request comments showing cost estimate diffs.

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1. Developer/DevOps proposes a change to the infrastructure

A Developer/DevOps makes changes to the infrastructure as code file, and creates a pull/merge request.

Infracost.io Configuration 5

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2. Infracost calculates the cost of the change

Infracost looks at the changes made to the Terraform file and shows the pre and post-change costs as a comment in the pull request: “This change will increase your bill by 27%”