Implementing Terraform CI/CD with AWS CodeBuild and Amazon S3 State Storage

Overview

Setting up a continuous integration pipeline for Terraform deployments doesn’t always require complex state locking mechanisms. This comprehensive guide demonstrates how to implement Terraform automation using AWS CodeBuild while storing state files in Amazon S3, bypassing the need for Amazon DynamoDB-based locking.

When to Consider Simplified State Management

Traditional Terraform deployments often incorporate Amazon DynamoDB for state locking to prevent concurrent modifications. However, certain scenarios make this approach unnecessary:

• Solo development environments where only one person manages the infrastructure
• Sequential deployment patterns with controlled execution timing
• Cost-sensitive projects seeking to minimize AWS service usage
• Prototype and testing environments with relaxed consistency requirements

This simplified approach prioritizes operational efficiency over concurrent access protection.

Architecture Components

Our implementation leverages these core AWS services:

• AWS CodeBuild: Provides the execution environment for Terraform operations
• Amazon S3: Serves dual purposes as a source code repository and state file storage
• AWS IAM: Manages access permissions and security boundaries
• Terraform: Handles infrastructure provisioning and management

Implementation Steps

Setting Up Amazon S3 Storage

Begin by creating an S3 bucket that will serve both as your Terraform code repository and state file storage location. This dual-purpose approach simplifies the architecture while maintaining separation of concerns through proper key prefixes.

aws s3 mb s3://your-terraform-deployment-bucket

AWS CodeBuild Project Configuration

Navigate to the AWS CodeBuild console and create a new build project with these specifications:

Project Settings:

• Choose a descriptive name reflecting your infrastructure’s purpose
• Configure appropriate tags for resource organization

Source Configuration:

• Select Amazon S3 as your source provider
• Specify the bucket containing your Terraform files
• Set the appropriate object key path

Environment Setup:

• Choose “Managed image” for standard environments or “Custom image” for specific Terraform versions.
• Select Ubuntu as the operating system
• Use the standard runtime with the appropriate compute size
• Consider using a public Terraform Docker image for consistency

Build Specification:

CreaSet up the build process using a buildspec.yml file structured as shown below:

Artifact Configuration:

• Configure Amazon S3 as the artifact destination
• Specify the path for storing generated state files
• Enable artifact encryption for security

Logging Setup:

• Enable Amazon CloudWatch Logs for build monitoring
• Configure appropriate log retention policies
• Set up log streaming for real-time debugging

Service Role Assignment:

When you create an AWS CodeBuild project, AWS automatically generates a service role for it. CodeBuild uses this role to perform actions on other AWS services as part of your build.

To ensure your Terraform deployments run smoothly, you need to attach the appropriate permissions to this role. The role should have access to:

• AWS services used by Terraform: For example, if your Terraform code creates Amazon EC2 instances, Amazon VPCs, AWS IAM roles, or other resources, you must explicitly allow those actions (like ec2:*, iam:*, vpc:*, etc.) in the role’s permissions.

Additionally, if you’re integrating with AWS CodePipeline or using reporting features, the role should also have permissions to access relevant Amazon S3 buckets and create test or coverage reports.

Always follow the principle of least privilege, only grant access to the resources your build needs.

Alternative Approaches and Considerations

Terraform Backend Configuration:

Configure your Terraform backend to use Amazon S3 storage for state file by adding this block to your main configuration:

Conclusion

This streamlined approach to Terraform automation provides an excellent foundation for infrastructure management without the complexity of state locking mechanisms. The combination of AWS CodeBuild’s managed environment and Amazon S3’s reliable storage creates a cost-effective solution suitable for many organizational needs.

While this setup doesn’t include concurrent access protection, it offers simplicity and reliability for controlled deployment scenarios. As your infrastructure requirements evolve, you can easily extend this foundation with additional features, such as state locking, approval workflows, and advanced monitoring.

Drop a query if you have any questions regarding Terraform and we will get back to you quickly.

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