AWS Fargate task fails ELB health checks

Solution 1:

You did not include the actual Load Balancer in your template. Please include that, for a full answer.

Your problem is most likely that your Load Balancer - which most likely has a private IP in your subnets and communicates with that - is not allowed to communicate with your ECS instances, since they allow only traffic from 138.106.0.0/16.

Solution 2:

For others, who might be facing the same issue:

It might be an issue with the route that you configured for health-check.

Your configured route should return a success response(status : 200) on GET call.

If "/" is the route you configured for health-check, please make sure you GET call to yourwebsitename.com/ returns a 200 status code.

Similarly, If "/health-check" you configured for health-check, please make sure you GET call to yourwebsitename.com/health-check returns a 200 status code.