AWS ECS ALB Error (Request timed out)

Question

I am trying to learn/use AWS ECS but keep getting

service has reached a steady state.

Followed by:

service (instance i-05873e2a55ecba2f6) (port 32768) is unhealthy in target-group due to (reason Request timed out)

I'm not really sure which info you need to help, but I was using this load balancer across EC2 instances before, but I am replacing those EC2 instances with ones launched through ECS and now I am running into this error.

My cluster is in my default VPC and I am including all 3 su.nets (East zone). The security group is my load balancer security group which allows all traffic on ports 40 and 443. I have tried changing security group so that it allows anyone on any port but that doesn't work.

My host port in my task definition is 0 and my container port is 3000 which is what I exposed in Dockerfile.

The healthcheck is just on the target port at path "/"

Answer 1

This answer summarize a checklist of points to verify when debugging this kind of error:

• be the case, there is no route Path /healthcheck in the backend service
• The status code from /healthcheck is not 200
• Might be the case that target port is invalid, configure it correctly, if an application running on port 8080 or 3000 it should be 3000 or 8080
• The security group is not allowing traffic on the target group
• Application is not running in the container

Answer 2

My problem was the same. Check the inbound rule of the security group of the ALB, there should be something like this. All traffic / All / All / "sg-xxxxxxxxxxxx" – .

sg-xxxxxxxxxxxx this should be the security group of your application load balancer.

Answer 3

Remember to check the outbound rule of your ALB security group. Target group health check actually issues the request from ALB. So if your ALB is not allowed to talk to your target, it will also fail.