My problem is similar to AWS: None of the Instances are sending data but has a slightly different error message.
I have a Rails application running on ElasticBeanstalk, and it appears to be running correctly. Periodically, Enhanced Health Monitoring sends me error messages such as:
Environment health has transitioned from Ok to Degraded. 20.0 % of the requests are failing with HTTP 5xx.
where the percentage varies up to 100%. Even though I've made no changes, a minute later I get a followup message telling me that everything is back to normal:
Environment health has transitioned from Degraded to Ok.
I've downloaded the full logs from ElasticBeanstalk but I don't know exactly where to look (there are around 20 different log files in various directories).
I'm currently using the free AWS tier with the smallest instances of database, server, etc. Could this be the cause? Which of the log files should I be looking in, and what should I be looking for?
I run rails apps on Elastic Beanstalk and have found it helpful to think about Beanstalk as a computer (in this case an Amazon EC2 instance) running your rails app and a web server (either Passenger or Puma). When you get a 500 error, it could be because your rails app didn't properly deploy–in which case Passenger or Puma will return an error—or your app is deployed properly but encountered an error just like it might on your local machine.
In either case, to diagnose an error, download the full logs from your AWS console (open the correct app environment and then choose Logs > Request Logs > Full logs > Download). Deployment errors are harder to diagnose, but I recommend starting by looking in var-XX/logs/log/eb-activity.log. I suspect your error is coming from your rails app itself, in which case I recommend looking in var-XX/app/support/logs/passenger.log and production.log. To find a 500 error, search for "500 Internal" and then treat the error like you would any other rails error.