Terragrunt

Terragrunt (Terraform/OpenTofu) Integration in Dash0

Terraform is a widely-used Infrastructure as Code (IaC) tool that allows users to define, provision, and manage cloud resources across multiple platforms using a declarative language called HashiCorp Configuration Language (HCL).

OpenTofu is an open-source fork of Terraform and now part of the Linux Foundation. It maintains backward compatibility with Terraform, allowing for seamless transitions and supporting existing workflows.

Terragrunt is a thin wrapper around Terraform/OpenTofu, that provides additional features to improve infrastructure management. It promotes DRY (Don't Repeat Yourself) configurations, simplifies remote state management, and offers versioning capabilities for Terraform/OpenTofu modules.

For more information, visit the Terragrunt Project Page.

Use Cases

Common use cases for Terragrunt in Dash0 include:

• Check which versions of Terragrunt are used across your infrastructure projects.
• Monitor the execution time of Terragrunt commands.

What Terragrunt/Terraform/OpenTofu commands are running and in which folders:

• Whether each command succeeded or failed.
• How long each command took.

What steps Terragrunt did internally (e.g., file system scanning, config parsing, auto-init, hook execution, etc) to process the command:

• How long each step took.
• Whether each step succeeded or failed.

What TF modules and providers, and at which versions, were used:

• How long it took to download them.
• How big they are on disk.

Install

Currently Terragrunt only supports sending telemetry data to a locally running OpenTelemetry collector. At Dash0 we run Atlantis on an EC2 instance with a locally running OpenTelemetry collector that collects all Terragrunt metrics, logs and traces.

Step 1: Run OpenTelemetry collector

For local experiments we recommend running the OpenTelemetry collector in a Docker container.

Please download this OpenTelemetry collector YAML configuration first and save it locally as config-blog-post.yaml

Then replace <DASH0_OTLP_ENDPOINT> and DASH0_AUTH_TOKEN in config-blog-post.yaml:

• DASH0_OTLP_ENDPOINT={{endpoint_otlp_grpc}}
• DASH0_AUTH_TOKEN={{token}}

Then you can start the collector using the following docker command:

docker run -p 4317:4317 -p 4318:4318 -v $(pwd)/config-blog-post.yaml:/etc/otelcol-contrib/config.yaml ghcr.io/open-telemetry/opentelemetry-collector-releases/opentelemetry-collector-contrib:0.114.0

Step 2: Configure Terragrunt environment variables

In your Terragrunt project directory, set the following environment variables. Once you run terragrunt plan / apply commands, the telemetry data will be sent to the OpenTelemetry collector.

export TERRAGRUNT_TELEMETRY_TRACE_EXPORTER=http
export TERRAGRUNT_TELEMETRY_TRACE_EXPORTER_HTTP_ENDPOINT=localhost:4318
export TERRAGRUNT_TELEMETRY_TRACE_EXPORTER_INSECURE_ENDPOINT=true

export TERRAGRUNT_TELEMETRY_METRIC_EXPORTER=grpcHttp
export TERRAGRUNT_TELEMETRY_METRIC_EXPORTER_INSECURE_ENDPOINT=true
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317

For more information, please refer to Terragrunt's documentation on OpenTelemetry.