What the reason for AWS Health status becoming RED?

Question

I've deployed an application to AWS elastic beanstalk.

after start the application, it runs well. But after 5 minutes(I set health check every 5 min), it runs failed. I access the url but HTTP 503 error back.

From the event info, I only get the info that the health status from YELLOW TO GREEN.

But how can I get detailed info and what can I do about this error?

BTW: I don't understand that is this health status RED leads to application can't start up OR something else failed leads to application failed, then the health status becomes to RED?

Answer 1

Elastic Load Balancing has a health check daemon that checks the path you've provided for a 200-range HTTP status.

If there is a problem with the application, or its not returning a 2xx status code, or if you've misconfigured the health check URL, the status will go RED.

Two things you can do to see what's going on:

1. Hit the hostname of an individual instance in your web browser — particularly the health check path. Are you seeing what you expected?

2. SSH into the instance and check the logs in /var/log and /opt/elasticbeanstalk/var/log. Are there any errors that you can find?

Without knowing more about your application, stack or container type, that's the best I can do.

I hope this helps! :)