AWS Blue/Green Deployment with Terraform and Elastic Beanstalk

What is Blue-Green Deployment:

Blue-Green Deployment is a modern infrastructure strategy designed to eliminate downtime during application updates, achieved by maintaining two identical production environments. The “Blue” environment serves live traffic while the “Green” environment hosts the new version for testing before a seamless traffic swap.

This approach addresses the fragility of traditional deployments where updates can lead to service interruptions and necessitates rollbacks, potentially costing businesses significant revenue and user trust. Large-scale outages due to failed deployments can total millions of dollars in lost revenue and damage reputation.

Key Insights

• DNS Propagation Time: Typical DNS propagation takes between a few minutes to 48 hours, representing the only potential downtime during a Blue/Green swap.
• Immutable Infrastructure: Blue-Green deployments align with immutable infrastructure principles, simplifying rollback procedures by reverting to the previous environment.
• Terraform for IaC: Terraform streamlines the deployment process, enabling repeatable and version-controlled infrastructure setup for both environments.

Working Example

# Application Version 1.0 (Blue Environment)
resource "aws_s3_object" "app_v1" {
  bucket = aws_s3_bucket.app_versions.id
  key    = "app-v1.zip"
  source = "${path.module}/app-v1/app-v1.zip"
  etag   = filemd5("${path.module}/app-v1/app-v1.zip")
  tags   = var.tags
}

resource "aws_elastic_beanstalk_application_version" "v1" {
  name             = "${var.app_name}-v1"
  application      = aws_elastic_beanstalk_application.app.name
  description      = "Application Version 1.0 - Initial Release"
  bucket           = aws_s3_bucket.app_versions.id
  key              = aws_s3_object.app_v1.id
  tags             = var.tags
}

resource "aws_elastic_beanstalk_environment" "blue" {
  name             = "${var.app_name}-blue"
  application      = aws_elastic_beanstalk_application.app.name
  solution_stack_name = var.solution_stack_name
  tier             = "WebServer"
  version_label    = aws_elastic_beanstalk_application_version.v1.name
}

Practical Applications

• Netflix: Uses a sophisticated Blue/Green deployment strategy for continuous delivery of new features with minimal disruption to its streaming service.
• Pitfall: Overly complex application setups can make environment synchronization challenging, increasing the risk of inconsistencies between Blue and Green environments.

References:

• https://dev.to/anil_kumar_noolu/day-17-aws-bluegreen-with-terraform-and-elastic-beanstalk-313m