Task Count Spike in Blue-Green Deployment: Step Scaling Increases Capacity, but Green Revision Fails to Launch

Question

I am using Blue/Green deployment for ECS service using AWS CodeDeploy, traffic shifted from blue to green, but after the shift, service metrics spiked. We are using step scaling, and the desired task count increased from 1 to 5. During this time, instances scaled, and the blue revision tasks launched successfully. However, the green revision tasks did not launch, even though enough space is present in capacity provider, After about 5 minutes, the single task in the green revision was deactivated, and I received the error "Deployment d-Q9CAKPUB7 External link failed. Error code: ECS_UPDATE_ERROR; Error message: CodeDeploy detected that the replacement task set is unhealthy. Rollback message: Deployment d-Q9CAKPUB7 External link terminated. Automatic rollback is triggered with a DeploymentId d-Q9CAKPUB7"

M Zubair Bin Ramzan · Answer

Verify ECS Health Checks: Ensure that your ECS service’s health checks are configured properly.

Review Auto Scaling Configurations: Check your capacity provider and ECS service scaling settings to ensure they can handle the task count increase.

Examine CodeDeploy Settings: Check the rollback settings, minimum healthy percentage, and deployment strategies in CodeDeploy.

Ensure Sufficient Resources: Verify that EC2 instances or Fargate tasks are not resource-constrained, preventing new tasks from starting.

Log and Monitor: Use CloudWatch logs and ECS events to investigate any specific errors or failures related to launching the green revision.

regards,
M Zubair
https://zeonedge.com

Task Count Spike in Blue-Green Deployment: Step Scaling Increases Capacity, but Green Revision Fails to Launch

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