Select your cookie preferences

We use essential cookies and similar tools that are necessary to provide our site and services. We use performance cookies to collect anonymous statistics, so we can understand how customers use our site and make improvements. Essential cookies cannot be deactivated, but you can choose “Customize” or “Decline” to decline performance cookies.

If you agree, AWS and approved third parties will also use cookies to provide useful site features, remember your preferences, and display relevant content, including relevant advertising. To accept or decline all non-essential cookies, choose “Accept” or “Decline.” To make more detailed choices, choose “Customize.”

Preferences
Contact Us
Feedback
AWS Documentation
Create an AWS Account
Application Load Balancer (ALB) - Prebid Server Deployment on AWS
Target HTTP 4xx error rateTarget HTTP 5xx error rateALB HTTP 4xx error rateALB HTTP 5xx error rateTarget response time (Latency)Unhealthy host count

Application Load Balancer (ALB)

PDF

Target HTTP 4xx error rate

  • The alarm changes state if there are 400 type status codes originating from the target (ECS). Reported as a percentage.

  • This indicates a bad request or a possible configuration error. Check the CloudWatch logs to get further detail on the cause of the error.

  • The alarm returns to the OK state if the error rate is within the acceptable threshold for 5 minutes.

  • Metric: HTTPCode_Target_4xxErrorRate > 1%

Target HTTP 5xx error rate

  • The alarm changes state if there are 500 type status codes originating from the target (ECS). Reported as a percentage.

  • This indicates a server failure. Check the CloudWatch logs to get further detail on the cause of the error.

  • The alarm returns to the OK state if the error rate is within the acceptable threshold for 5 minutes.

  • Metric: HTTPCode_Target_5xxErrorRate > 0%

ALB HTTP 4xx error rate

  • The alarm changes state if there are 400 type status codes originating from ALB. Reported as a percentage.

  • This indicates a bad request or a possible configuration error. Check the CloudWatch logs to get further detail on the cause of the error.

  • The alarm returns to the OK state if the error rate is within the acceptable threshold for 5 minutes.

  • Metric: HTTPCode_ELB_4xxErrorRate > 1%

ALB HTTP 5xx error rate

  • The alarm changes state if there are 500 type status codes originating from the target ALB. Reported as a percentage.

  • This indicates a server failure. Check the CloudWatch logs to get further detail on the cause of the error.

  • The alarm returns to the OK state if the data is within the acceptable threshold for 5 minutes.

  • Metric: HTTPCode_ELB_5xxErrorRate > 0%

Target response time (Latency)

  • The alarm changes state if there is a large amount of latency (greater than 100ms) reported within a 1-minute period.

  • This could indicate a performance issue or scaling failure from ECS. Check the CloudWatch logs to get further detail on the cause of the error.

  • The alarm returns to the OK state if the data is within the acceptable threshold for 5 minutes.

  • Metric: TargetResponseTime average > 100 ms

Unhealthy host count

  • The alarm changes state if there is a target that is considered unhealthy within a 1-minute period.

  • The alarm returns to the OK state if the data is within the acceptable threshold for 5 minutes.

  • Check the CloudWatch logs to get further detail on the cause of the error.

  • Metric: UnhealthyHotCount > 0

Next topic:

NAT gateway

Previous topic:

CloudFront

Need help?

PrivacySite termsCookie preferences
© 2025, Amazon Web Services, Inc. or its affiliates. All rights reserved.