I have a Go server that is currently running with Kubernetes on AWS. The website sits under a route-53 and an ELB that manages the SSL termination. Now, I want to support HTTP/2 in my web-server in order to push resources to the clients, and I saw that HTTP/2 requires that the web-server will use HTTPS. I have a few questions according to that.
HTTP/2 requires HTTPS - In my case the HTTPS logic is in the ELB and it manages for me the SSL termination. My application gets the decrypted data as a simple HTTP request. Do I need to remove the ELB in order to enable HTTP/2 in my web-server? Is there any way to leave the ELB there and enable HTTP/2 in my web-server?
In my local development I use openssl to generate certificate. If I deploy the web-server I need to get the CA certificate from AWS and store it somewhere in the Kubernetes certificate-manager and inject to my web-server in the initialization. What is the recommended way to do this?
I feel like I miss something, so I'll appreciate any help. Thanks
There is no benefit to deploying HTTP2 on an AWS load balancer if your backend is not HTTP2 also. Technically HTTP2 does not require HTTPS, but nobody implements HTTP2 for HTTP. HTTP2 is a protocol optimization (simple viewpoint) that removes round trips in the SSL negotiation, improves pipelining, etc. If the load balancer is communicating with your backend via HTTP, there will not be any improvement. The load balancer will see a small decrease in load due to reduced round trips during HTTPS setup.
I recommend that you configure your backend services to only use HTTPS (redirect clients to HTTPS) and use an SSL certificate. Then configure HTTP2, which is not easy by the way. You can use Let's Encrypt for SSL which works very well. You can also use OpenSSL self-signed certificates (which I don't recommend). You cannot use AWS services to create SSL certificates for your backend services, only for AWS managed services (CloudFront, ALB, etc.).
You can also setup the load balancer with Layer 4 (TCP) listeners. This is what I do when I setup HTTP2 on my backend servers. Now the entire path from client to backend is using HTTP2 without double SSL encryption / decryption layers.
One of the nice features of load balancers is called "SSL offloading". This means that you enable SSL on the load balancer and only enable HTTP on your backend web servers. This goes against HTTP2. Therefore think thru what you really want to accomplish and then design your services to meet those objectives.
Another point to consider. Since you are looking into HTTP2, at the same time remove support in your services for the older TLS versions and unsafe encryption and hashing algorithms. Dropping TLS 1.0 should be mandatory today and I recommend dropping TLS 1.1 also. Unless you really need to support ancient browsers or custom low-end hardware, TLS 1.2 should be the standard today. Your logfiles can tell you if clients are connecting via older protocols.