Using a S3 Static Site with an Application Load Balancer

Question

I have an ALB that currently routes traffic to multiple urls. I'd like to be able to route traffic to a Static S3 site in the event that we need to perform maintenance. We would then display a static "Maintenance" page instead of our login page.

I have created a CloudFront Distribution that allows a S3 site to be loaded with an SSL cert but I am not sure how to connect that distribution to send all of the traffic to the S3 maintenance site.

This is the Terraform ALB listener I'm using. Can I specify my CloudFront distribution arn at the target_group and have it route all traffic to the static site?

Or could I simply link my S3 arn here with an S3 policy allowing the ALB access to get the bucket objects?

resource "aws_alb_listener" "ssl_alb_httpslistener" {
   load_balancer_arn = "${aws_alb.alb_lis.arn}"
   port = "443"
   protocol = "HTTPS"
   ssl_policy = "Sec-TLS"
   certificate_arn = "${var.ssl_cert_arn}"

    default_action {
     target_group_arn = "${data.terraform_remote_state.php.target_arn}"
     type = "forward"
   }
}

I would I expect that I could route traffic that passes through an ALB to a Static S3 site from the target_group. Curious if this is the best way to go about this.

Berm

Answer 1

The simple answer is to use a redirect option on the ALB to forward traffic to a new url. My Route53 url is connected to a CloudFront Distribution linked to the S3 bucket. Here I was able to specify a single redirect url and keep my HTTPS traffic options with minimal infrastructure modifications.

Berm

If r53 is pointing to Cfront, how is it actually going through the LB? A redirect would need to be done to another url, but then it would fail in cfront as the hostname is changed, wouldn't it? – Goutweed

Answer 2

You can now have Lambda function as target group and with Lambda, you can trigger S3 , make cloudfront(http) GET request etc.

Polygamist

the problem with lambda is, that the body of the request can only be 1MB. I Got the same issue when serving an Angular app. I could not load the main..*.js because it was 1.4 MB. Still looking for another solution, because we want to have front- and backend under the same host. If someone got a solution, please comment! – Meetly

Answer 3

I faced the same issue of 1MBytes limit with ALB and lambdas and used compression as a workaround. Set in response headers Content-Encoding= and compress your file(s) accordingly.

Woodnote