Target group health checks fail AWS

Question

I am pretty new to AWS

I have a Golang app deployed on Elasticbeanstalk. All worked fine when it was a single instance app, without using load balancing.

However, when I introduce a load balancer, I cannot access a website at all.

The app is running on port 8080.

Here is my elastic beanstalk listeners configuration

Also, here is ALB configuration:

Target group health check fails with Request timeout. It's configured to route / which should work.

Security groups should be fine, I've create inbound rules for ports 5432 (need it for postgres), 8080 etc. All worked fine on single instance environment

Now, I am not able to access my app via port 8080 (nor via 80 nor via 443 - ssl), of course not via custom domain

I did not include details of certificate and custom domain on purpose, wanted to isolate this problem

What can be an issue and how can I debug this?

Answer 1

Issue is resolved

There were wrong subnets specified on Elasticbeanstalk

When I created min 1, max 2 instances and specified 2 subnets in 2 availability zones, all started working fine

There was no issue in Security groups nor Targets

Thanks for help!