Today, we will see how to troubleshoot a bad gateway error in AWS Elastic Beanstalk. As a part of our AWS Support Services, Bobcares provides solutions to your AWS queries.

Bad Gateway In AWS Beanstalk

A web server will issue an HTTP 502 bad gateway error if it receives an incorrect response from the backend end server with which it is communicating. While working with the AWS EB, we may see an HTTP 502 Bad Gateway Error. The service may later resume and things will start to function normally.

The cause behind this issue in the AWS EB makes us wonder. So in this article, we will look into some of the possible reasons for the AWS Beanstalk bad gateway error, along with the solution to fix the error.

Possible Causes Of AWS Beanstalk Bad Gateway

AWS EB contains 3 parts, namely Elastic Load Balancer, Nginx web server, and Tomcat Application server. The error may arise due to any of the parts. By closely looking into the error message, we may know the part causing the issue. In this article, we consider the issue is caused by an Nginx server.

According to the HTTP 502 error description, Nginx should throw this issue only if it receives an incorrect response from the Tomcat server. To find the root of the problem, run the open-source yCrash script on the EC2 instance where the Tomcat server is running. The yCrash script will collect 16 distinct artifacts from the technological stack. Then upload the captured artifacts into the yCrash server for analysis.

A kernel log file is one of the artifacts captured by the yCrash script. All events that occurred in the Linux kernel can be found in this log file. yCrash extracts and shows critical errors and warnings from the log file.

When the yCrash’s Kernel log analysis reports the following error, it shows the Tomcat server which is a Java process was terminated. The Linux kernel terminated the Tomcat server whenever the application’s memory consumption exceeded the capacity restrictions.

We might question why halting the Tomcat server on Linux does not result in a total outage, but rather in an intermittent HTTP 502 bad gateway problem. The application is hosted on AWS EBS. When the EBS service ends, it will automatically restart the Tomcat server. EBS is also restarting the Tomcat server when Linux is terminating. Customers were experiencing HTTP 502 bad gateway issues during this period.

How To Fix AWS Beanstalk Bad Gateway?

Increasing the RAM capacity of an EC2 instance: The RAM capacity of EC2 instances is only 1GB. The memory was insufficient to run all the services. As a result, the problem was solved when the program was upgraded to run on a 2GB RAM capacity EC2 instance.

[Looking for a solution to another query? We’re here to help.]

Conclusion

In this article, we briefly describe the possible cause of the AWS Beanstalk Bad Gateway error. We also recommend a simple solution from our Tech team to fix the error.