SSL for subdomains using different AWS ELB (EC2)

Question

I have:

ELB 1 with few ec2 instances attached: - example.com - subdomain1.example.com - subdomain2.example.com

ELB 2 with few ec2 instances attached: - subdomain3.example.com subdomain4.example.com

All domains\subdomains should have https. It is okay for me to keep non-secure connection between instances and load balancer.

Is this possible to have more than one subdomains on one loadbalancer or I have to keep one loadbalancer for one subdomain?

Answer 1

If all domains and subdomains should have HTTPS, your best move is to deploy a SSL certificate for those domains/subdomains in the ELB and configure SSL termination at it. That being said, you are able to add multiple SANs (Subject Alternative Names) to your SSL certificates, making your ELB respond to multiple domains/subdomains over HTTPS.

This way, the traffic between your ELBs and your instances won't be over HTTPS, but you said that is not a problem. Actually, this is pretty much the default configuration on ELBs when HTTPS is needed.