Terraform aws_cloudfront_distribution Deep Dive

Infrastructure as Code changes how CloudFront is provisioned. Configuring CloudFront through the console is painful with dozens of settings spread across multiple screens. Terraform turns all of that into a single, readable configuration file. The AWS CloudFront Terraform module enables you to efficiently provision and manage CloudFront distributions through Infrastructure as Code. The guide provides comprehensive instructions for using the AWS CloudFront Terraform module. It explains how to configure and implement CloudFront distributions using the Terraform AWS provider, covering basic to advanced usage patterns, key configuration options, and integration patterns with other AWS resources.

What Terraform Brings to CloudFront

CloudFront is AWS's content delivery network, and it does a lot more than just caching static files. It handles SSL termination, custom domains, request routing, edge functions, and geographic restrictions. Terraform is an open-source IaC tool that permits clients to characterize and automate the deployment of Infrastructure.

In Terraform, a provider is liable for overseeing assets in a particular cloud or service. For AWS, the provider is "aws." without a provider we cannot create an infrastructure by using Terraform. A resource is a block in Terraform setup that defines a particular infrastructure part, e.g., EC2 instance, S3 bucket, CloudFront distribution. A variable is a parameter in Terraform that allows you to enter values dynamically, giving adaptability to your infrastructure definitions. A module is an assortment of Terraform configuration files and scripts gathered to make reusable and shareable parts. State is the record of the present status of the foundation overseen by Terraform.

Managing CloudFront distributions can be a complex task, requiring constant updates to configuration files and balancing performance, security, and scalability. Terraform, an infrastructure as code tool, simplifies this process by allowing you to define infrastructure in a human-readable configuration file.

Module Architecture and Capabilities

The AWS CloudFront Terraform module enables you to efficiently provision and manage CloudFront distributions through Infrastructure as Code. The module handles the creation and configuration of CloudFront distributions and related resources, including Origin Access Identities, Origin Access Controls, VPC Origins, and monitoring subscriptions.

For module architecture details, see Module Architecture. The module requires at minimum sources for configuration. To use the module, include it in your Terraform configuration and provide the necessary parameters.

The module allows you to configure various aspects of your CloudFront distribution. Key distribution settings include:

Setting	Description	Default
aliases	CNAMEs (alternate domain names) for the distribution	null
comment	Description for the distribution	null
enabled	Whether the distribution is enabled	true
isipv6enabled	Whether IPv6 is enabled	null
price_class	Distribution price class (e.g., PriceClass_All)	null
http_version	Maximum HTTP version to support	"http2"
waitfordeployment	Whether to wait for deployment to complete	true
webaclid	ID of AWS WAF web ACL to associate with distribution	null
staging	Whether this is a staging distribution	false

The module supports multiple origin types. For S3 bucket origins, you can use either Origin Access Identity (OAI, legacy) or Origin Access Control (OAC, recommended). For custom web servers, configuration is supported. For origins inside a VPC, configuration is supported.

Core Concepts of CloudFront Distributional Model

Every Distribution has a one of a kind CloudFront domain name. Origin is the source of the files that CloudFront delivers to clients. This can be an Amazon S3 container, an HTTP server, or other web servers. Edge Area is the physical location where content is stored and served to clients. These are decisively positioned all over the planet to guarantee low-inactivity access. Viewer Certificate is an SSL/TLS certificate used to scramble the association between CloudFront and end-users. It tends to be the default CloudFront certificate or a custom uploaded transferred to AWS Identity and Access Management (IAM).

The most common pattern is serving static assets from an S3 bucket through CloudFront. Let's walk through building CloudFront distributions for the two most common use cases: serving a static website from S3, and putting CloudFront in front of an API.

Basic Usage Pattern

Basic usage starts with a minimal resource definition.

hcl resource "aws_cloudfront_distribution" "example" { origin { domain_name = "example.com" origin_id = "example.com" } enabled = true }

This configuration file creates a CloudFront distribution with a single origin server and a custom cache behavior. The origin block defines the source domain name and a logical origin_id used to reference the origin in cache behaviors.

Advanced Configuration with Cache Behavior and Restrictions

Advanced usage adds cache behavior controls, viewer protocol policy, and geo restrictions.

hcl resource "aws_cloudfront_distribution" "example" { origin { domain_name = "example.com" origin_id = "example.com" } enabled = true default_cache_behavior { allowed_methods = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"] cached_methods = ["GET", "HEAD"] target_origin_id = "example.com" forwarded_values { query_string = false cookies { forward = "none" } } viewer_protocol_policy = "redirect-to-https" min_ttl = 0 default_ttl = 3600 max_ttl = 86400 } restrictions { geo_restriction { restriction_type = "whitelist" locations = ["US", "CA", "GB"] } } viewer_certificate { cloudfront_default_certificate = true } }

The configuration shows allowedmethods covering the full HTTP method set, cachedmethods limited to safe methods, forwardedvalues with querystring false and cookies forward set to none, viewerprotocolpolicy set to redirect-to-https, and TTL values for cache control. Geo restriction is configured with restriction_type whitelist and locations US, CA, GB.

Outputs and State Management

Outputs expose distribution identifiers after apply.

hcl output "cloudfront_distribution_id" { value = aws_cloudfront_distribution.example.id } output "cloudfront_distribution_domain_name" { value = aws_cloudfront_distribution.example.domain_name }

This file outputs the CloudFront distribution ID and domain name. Output the CloudFront Distribution ID and Domain Name. The state file records the present status of the foundation overseen by Terraform, allowing subsequent plans to detect drift.

Origin Access Patterns

Origin Access Identity and Origin Access Control are central to secure S3 origins. The module handles the creation and configuration of CloudFront distributions and related resources, including Origin Access Identities, Origin Access Controls, VPC Origins, and monitoring subscriptions.

For S3 bucket origins, you can use either Origin Access Identity (OAI, legacy) or Origin Access Control (OAC, recommended). The choice affects how CloudFront authenticates to the S3 bucket and what IAM policies are generated.

For custom web servers, the origin block can point to an HTTP or HTTPS endpoint. For origins inside a VPC, VPC origins are supported through the module.

Integration Patterns with Other AWS Resources

The guide provides comprehensive instructions for using the AWS CloudFront Terraform module. It explains how to configure and implement CloudFront distributions using the Terraform AWS provider, covering basic to advanced usage patterns, key configuration options, and integration patterns with other AWS resources.

Integration typically involves referencing the distribution domain name in DNS records, associating a Web ACL via webaclid, and configuring viewer certificates for custom domains. The module allows you to configure various aspects of your CloudFront distribution and related resources.

Operational Workflow

Infrastructure as Code (IaC) is a technique for overseeing and provisioning framework utilizing code instead of manual cycles. Terraform is an open-source IaC tool that permits clients to characterize and automate the deployment of Infrastructure.

A typical workflow is:
- Define provider and region
- Declare variables for domain names, origin details, and restrictions
- Use the awscloudfrontdistribution resource or the module to declare distribution
- Configure origin blocks and cache behaviors
- Define outputs for distribution ID and domain name
- Run terraform init, terraform plan, terraform apply

Managing CloudFront distributions can be a complex task, requiring constant updates to configuration files and balancing performance, security, and scalability. Terraform simplifies this process by allowing you to define infrastructure in a human-readable configuration file.

Common Configuration Options

The module allows you to configure various aspects of your CloudFront distribution. Key distribution settings include aliases for CNAMEs, comment for description, enabled flag, isipv6enabled, priceclass, httpversion, waitfordeployment, webaclid, and staging flag.

The module supports multiple origin types. For S3 bucket origins, you can use either Origin Access Identity (OAI, legacy) or Origin Access Control (OAC, recommended). For custom web servers, configuration is available. For origins inside a VPC, configuration is supported.

Conclusion

Terraform awscloudfrontdistribution provides a declarative, versioned approach to CloudFront. The AWS CloudFront Terraform module enables you to efficiently provision and manage CloudFront distributions through Infrastructure as Code. The module handles the creation and configuration of CloudFront distributions and related resources, including Origin Access Identities, Origin Access Controls, VPC Origins, and monitoring subscriptions.

Basic usage demonstrates a minimal origin and enabled flag. Advanced usage shows custom cache behavior with allowed methods, cached methods, forwarded values, viewer protocol policy, TTLs, geo restrictions, and viewer certificate configuration. Outputs expose distribution ID and domain name for downstream consumption.

The module requires at minimum sources for configuration and allows configuration of aliases, comment, enabled, isipv6enabled, priceclass, httpversion, waitfordeployment, webaclid, and staging. CloudFront is AWS's content delivery network, and it does a lot more than just caching static files. It handles SSL termination, custom domains, request routing, edge functions, and geographic restrictions. Terraform turns all of that into a single, readable configuration file.