Hello! On Thu, Oct 16, 2014 at 10:17:15AM +0200, Jiri Horky wrote:
> Hi list, > > we are seeing sporadic nginx errors "upstream prematurely closed > connection while reading response header from upstream" with nginx/1.6.2 > which seems to be some kind of race condition. > For debugging purposes we only setup 1 upstream server on a public IP > address of the same server as nginx, there is no keepalive configured > between nginx and the upstream server. The upstream HTTP server is > written in a way that it forcibly closes the connection when the > response status code is 303. This may be part of the problem as well. [...] > Now, we tracked down, that this only happens when FIN packet from > upstream server reaches nginx sooner than it's finished with parsing the > response (headers) and thus sooner than nginx closes the connection > itself. For example this packet order will trigger the problem: > No. Time Source SrcPrt Destination Protocol > Length Info > 25571 10.297569 1.1.1.1 35481 1.1.1.1 TCP 76 > 35481 > 8888 [SYN] Seq=0 Win=3072 Len=0 MSS=16396 SACK_PERM=1 > TSval=1902164528 TSecr=0 WS=8192 > 25572 10.297580 1.1.1.1 8888 1.1.1.1 TCP 76 > 8888 > 35481 [SYN, ACK] Seq=0 Ack=1 Win=3072 Len=0 MSS=16396 SACK_PERM=1 > TSval=1902164528 TSecr=1902164528 WS=8192 > 25573 10.297589 1.1.1.1 35481 1.1.1.1 TCP 68 > 35481 > 8888 [ACK] Seq=1 Ack=1 Win=8192 Len=0 TSval=1902164528 > TSecr=1902164528 > 25574 10.297609 1.1.1.1 35481 1.1.1.1 HTTP 1533 > GET / HTTP/1.0 > 25575 10.297617 1.1.1.1 8888 1.1.1.1 TCP 68 > 8888 > 35481 [ACK] Seq=1 Ack=1466 Win=8192 Len=0 TSval=1902164528 > TSecr=1902164528 > 25596 10.323092 1.1.1.1 8888 1.1.1.1 HTTP 480 > HTTP/1.1 303 See Other > 25597 10.323106 1.1.1.1 35481 1.1.1.1 TCP 68 > 35481 > 8888 [ACK] Seq=1466 Ack=413 Win=8192 Len=0 TSval=1902164554 > TSecr=1902164554 > 25598 10.323161 1.1.1.1 8888 1.1.1.1 TCP 68 > 8888 > 35481 [FIN, ACK] Seq=413 Ack=1466 Win=8192 Len=0 TSval=1902164554 > TSecr=1902164554 > 25599 10.323167 1.1.1.1 35481 1.1.1.1 TCP 68 > 35481 > 8888 [FIN, ACK] Seq=1466 Ack=413 Win=8192 Len=0 TSval=1902164554 > TSecr=1902164554 > 25600 10.323180 1.1.1.1 8888 1.1.1.1 TCP 68 > 8888 > 35481 [ACK] Seq=414 Ack=1467 Win=8192 Len=0 TSval=1902164554 > TSecr=1902164554 > 25601 10.323189 1.1.1.1 35481 1.1.1.1 TCP 68 > 35481 > 8888 [ACK] Seq=1467 Ack=414 Win=8192 Len=0 TSval=1902164554 > TSecr=1902164554 > > Note that the upstream HTTP (port 8888) sends the FIN packet sooner than > nginx (port 35481 in this case). Looking into the packet trace I suspect this commit may be relevant to your case: http://hg.nginx.org/nginx/rev/9d3a9c45fc43 Please test with nginx 1.7.3+ to see if it helps. -- Maxim Dounin http://nginx.org/ _______________________________________________ nginx mailing list [email protected] http://mailman.nginx.org/mailman/listinfo/nginx
