Use HTTP/2.0 between nginx reverse-proxy and backend webserver

I use nginx as a reverse-ssl-proxy in front of a backend webserver that is capable of doing HTTP/2.0.

I noticed that nginx proxies the requests to the backend server via HTTP/1.1 rather than HTTP/2.0. Is it possible to tell nginx to use an un-encrypted HTTP/2.0 connection instead? Would this increase performance?

Solution 1:

Found this: https://trac.nginx.org/nginx/ticket/923

There are no plans to implement HTTP/2 support in the proxy module in the foreseeable future

Excerpt from a mail referenced in the ticket:

There is almost no sense to implement it, as the main HTTP/2 benefit is that it allows multiplexing many requests within a single connection, thus [almost] removing the limit on number of simalteneous requests - and there is no such limit when talking to your own backends. Moreover, things may even become worse when using HTTP/2 to backends, due to single TCP connection being used instead of multiple ones.

Solution 2:

Sadly nginx not support proxy to a http/2 backend server, referenced from https://www.nginx.com/blog/http2-module-nginx/#QandA

Q: Will you support HTTP/2 on the upstream side as well, or only support HTTP/2 on the client side?

A: At the moment, we only support HTTP/2 on the client side. You can’t configure HTTP/2 with proxy_pass. [Editor – In the original version of this post, this sentence was incorrectly transcribed as “You can configure HTTP/2 with proxy_pass.” We apologize for any confusion this may have caused.]

But what is the point of HTTP/2 on the backend side? Because as you can see from the benchmarks, there’s not much benefit in HTTP/2 for low‑latency networks such as upstream connections.

Also, in NGINX you have the keepalive module, and you can configure a keepalive cache. The main performance benefit of HTTP/2 is to eliminate additional handshakes, but if you do that already with a keepalive cache, you don’t need HTTP/2 on the upstream side.

Solution 3:

As of version 1.13.9 http2 is supported for server pushes.

One way is to define a list of assets that you would like pushed back upon a request to a specific location using the http2_push statement.

A second way is to let nginx intercept the response and push the link tags with the preload attribute using the http2_push_preload statement.

More details in the blog post that @malix referenced in the comments of the OP