Instances are not healthy

Question

I created an Application load balancer in two different AZs and started my web server in the private subnet. I followed the AWS instruction document to create a network load balancer.

I tried to launch the network load balancer but it did not work. I checked my routing and security group. I have made it allow all protocols for all ports for both incoming and outgoing, but still, it is not working. I also suffixed the index.html to the DNS url but it still failed. I checked the health of the target group and it is healthy and i am able to ssh into all the EC2 instance and the web servers are up and running. Strangely nslookup for the DNS name of Loadbalance resolves the ip addresses linked in the Loadbalancer.

Answer 1

Reason: You might have created the load balancer in private subnet which doesn't contain internet access. But you are trying to access those pages on the internet.

Solution: You need to launch the load balancer inside the public subnet and then in the targets you need to give the instance present in private this will act as a gateway and route the traffic from the browser to private subnets and display it on the browser.

 For more details, refer to this AWS Tutorial