Download pdf fails Backend proto h2


I’m experiencing an issue with my current configuration, which involves High Availability (HA) setup connecting to Apache, which communicates with Tomcat. The problem arises when attempting to download a PDF file, as it appears to be getting truncated.

We have observed the following regarding our issue:
When obtaining the PDF file directly from either Apache or Tomcat without involving the HA component, it functions correctly.
Removing the ‘proto h2’ option from the configuration resolves the issue.
The problem appears to be limited to URLs with parameters, where it doesn’t work as expected.

Any help will be welcome. Thank you.

backend xxxxx
balance roundrobin
option forwardfor
cookie SERVERID insert indirect nocache
server servername ip:port check cookie h40 proto h2

HAProxy version 2.6.12-f588462 2023/03/28 -
Status: long-term supported branch - will stop receiving fixes around Q2 2027.
Known bugs:
Running on: Linux 4.18.0-477.21.1.el8_8.x86_64 #1 SMP Tue Aug 8 21:30:09 UTC 2023 x86_64
Build options :
TARGET = linux-glibc
CPU = generic
CC = cc
CFLAGS = -O2 -g -Wall -Wextra -Wundef -Wdeclaration-after-statement -Wfatal-errors -Wtype-limits -Wshift-negative-value -Wshift-overflow=2 -Wduplicated-cond -Wnull-dereference -fwrapv -Wno-address-of-packed-member -Wno-unused-label -Wno-sign-compare -Wno-unused-parameter -Wno-clobbered -Wno-missing-field-initializers -Wno-cast-function-type -Wno-string-plus-int -Wno-atomic-alignment


Default settings :
bufsize = 16384, maxrewrite = 1024, maxpollevents = 200

Built with multi-threading support (MAX_THREADS=64, default=4).
Built with OpenSSL version : OpenSSL 1.1.1k FIPS 25 Mar 2021
Running on OpenSSL version : OpenSSL 1.1.1k FIPS 25 Mar 2021
OpenSSL library supports TLS extensions : yes
OpenSSL library supports SNI : yes
OpenSSL library supports : TLSv1.0 TLSv1.1 TLSv1.2 TLSv1.3
Built with Lua version : Lua 5.4.4
Built with network namespace support.
Built with the Prometheus exporter as a service
Support for malloc_trim() is enabled.
Built with zlib version : 1.2.11
Running on zlib version : 1.2.11
Compression algorithms supported : identity(“identity”), deflate(“deflate”), raw-deflate(“deflate”), gzip(“gzip”)
Built with transparent proxy support using: IP_TRANSPARENT IPV6_TRANSPARENT IP_FREEBIND
Built with PCRE version : 8.42 2018-03-20
Running on PCRE version : 8.42 2018-03-20
PCRE library supports JIT : yes
Encrypted password support via crypt(3): yes
Built with gcc compiler version 8.5.0 20210514 (Red Hat 8.5.0-16)

Available polling systems :
epoll : pref=300, test result OK
poll : pref=200, test result OK
select : pref=150, test result OK
Total: 3 (3 usable), will use epoll.

Available multiplexer protocols :
(protocols marked as cannot be specified using ‘proto’ keyword)
h2 : mode=HTTP side=FE|BE mux=H2 flags=HTX|HOL_RISK|NO_UPG
fcgi : mode=HTTP side=BE mux=FCGI flags=HTX|HOL_RISK|NO_UPG
: mode=HTTP side=FE|BE mux=H1 flags=HTX
h1 : mode=HTTP side=FE|BE mux=H1 flags=HTX|NO_UPG
: mode=TCP side=FE|BE mux=PASS flags=
none : mode=TCP side=FE|BE mux=PASS flags=NO_UPG

Available services : prometheus-exporter
Available filters :
[CACHE] cache
[COMP] compression
[FCGI] fcgi-app
[SPOE] spoe
[TRACE] trace