I'm deploying an apparently simple CloudFormation template from AWS samples: https://s3-ap-northeast-1.amazonaws.com/cloudformation-templates-ap-northeast-1/vpc_multiple_subnets.template
As stated, it should "...create a VPC with multiple subnets. The first subnet is public and contains the load balancer, the second subnet is private and contains an EC2 instance behind the load balancer."
However, I can't reach the instance through the balancer public DNS Name.
The balancer
- shows the instance as "OutOfService" (but it's running)
- has a health checker and listener on port 80.
- run inside a vpc and the vpc has attached an IGW
- run in the same AZ as the instance
- has a security group with inbound and outbound HTTP access rule from anywhere
the instance
- is in a private subnet of the same VPC
- has a security group that accepts inbound HTTP traffic from the balancer security group and outbound to anywhere
If I curl the balancer I get 503, like if the traffic is reaching the balancer but not the instance.
I'm at loss, I don't know how to troubleshoot more than this.
EDIT: maybe that instance has no web server in it?