nginx protocol_error ai_generated partial

upstream sent HTTP/2.0 response while reading response header from upstream

ID: nginx/upstream-sent-http-2-0-response-while-reading-response-header-from-upstream

Also available as: JSON · Markdown · 中文

80%Fix Rate

85%Confidence

1Evidence

2024-06-25First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
nginx 1.18.0	active	—	—	—
nginx 1.20.0	active	—	—	—
nginx 1.22.0	active	—	—	—
nginx 1.24.0	active	—	—	—

Root Cause

Upstream server responded with HTTP/2 (HTTP/2.0) but nginx is configured to use HTTP/1.x for proxying, causing a protocol mismatch.

generic

中文

上游服务器以HTTP/2（HTTP/2.0）响应，但nginx配置为使用HTTP/1.x进行代理，导致协议不匹配。

Official Documentation

https://nginx.org/en/docs/http/ngx_http_v2_module.html

Workarounds

80% success Configure nginx to proxy using HTTP/2 by setting proxy_http_version 2.0; (requires nginx compiled with HTTP/2 support and ngx_http_v2_module): location / { proxy_http_version 2.0; proxy_pass https://upstream; # Note: HTTPS required for HTTP/2 }
```
Configure nginx to proxy using HTTP/2 by setting proxy_http_version 2.0; (requires nginx compiled with HTTP/2 support and ngx_http_v2_module):

location / {
    proxy_http_version 2.0;
    proxy_pass https://upstream;  # Note: HTTPS required for HTTP/2
}
```
75% success If the upstream is an HTTP/2 server, configure it to also support HTTP/1.1. For example, in a Node.js server using http2 module: const http2 = require('http2'); const http = require('http'); const server = http2.createServer(); server.on('stream', (stream, headers) => { stream.respond({ ':status': 200 }); stream.end('OK'); }); server.listen(8080); Add an HTTP/1.1 listener on a different port if needed.
```
If the upstream is an HTTP/2 server, configure it to also support HTTP/1.1. For example, in a Node.js server using http2 module:

const http2 = require('http2');
const http = require('http');

const server = http2.createServer();
server.on('stream', (stream, headers) => {
    stream.respond({ ':status': 200 });
    stream.end('OK');
});
server.listen(8080);

Add an HTTP/1.1 listener on a different port if needed.
```
70% success Use a load balancer like HAProxy that can convert HTTP/2 to HTTP/1.1: frontend http-in bind *:80 default_backend servers backend servers server upstream1 10.0.0.1:8080 proto h2 HAProxy can terminate HTTP/2 and forward as HTTP/1.1 to nginx.
```
Use a load balancer like HAProxy that can convert HTTP/2 to HTTP/1.1:

frontend http-in
    bind *:80
    default_backend servers

backend servers
    server upstream1 10.0.0.1:8080 proto h2

HAProxy can terminate HTTP/2 and forward as HTTP/1.1 to nginx.
```

中文步骤

Configure nginx to proxy using HTTP/2 by setting proxy_http_version 2.0; (requires nginx compiled with HTTP/2 support and ngx_http_v2_module):

location / {
    proxy_http_version 2.0;
    proxy_pass https://upstream;  # Note: HTTPS required for HTTP/2
}

If the upstream is an HTTP/2 server, configure it to also support HTTP/1.1. For example, in a Node.js server using http2 module:

const http2 = require('http2');
const http = require('http');

const server = http2.createServer();
server.on('stream', (stream, headers) => {
    stream.respond({ ':status': 200 });
    stream.end('OK');
});
server.listen(8080);

Add an HTTP/1.1 listener on a different port if needed.

Use a load balancer like HAProxy that can convert HTTP/2 to HTTP/1.1:

frontend http-in
    bind *:80
    default_backend servers

backend servers
    server upstream1 10.0.0.1:8080 proto h2

HAProxy can terminate HTTP/2 and forward as HTTP/1.1 to nginx.

Dead Ends

Common approaches that don't work:

90% fail
If the upstream only supports HTTP/2, forcing HTTP/1.1 will not change the upstream's response; the upstream will still send HTTP/2 responses.
95% fail
Buffer size does not affect protocol version negotiation.
85% fail
These headers are for WebSocket upgrades, not HTTP version negotiation.