[scl.org] httpd24 and http/2

Joe Orton jorton at redhat.com
Tue Oct 17 15:34:21 UTC 2017

Hi Joni,

On Fri, Oct 13, 2017 at 12:33:08PM +0000, Joni Herttuainen wrote:
> The apache of httpd24 provided by SCL is recent enough to support
> HTTP/2. But when I installed the package and configured it, I could not
> get the communication in h2 protocol to work.
> First of all, there was an error message when loading the mod_http2:
> > httpd: Syntax error on line 56 of
> > /opt/rh/httpd24/root/etc/httpd/conf/httpd.conf: Syntax error on line
> > 40 of /opt/rh/httpd24/root/etc/httpd/conf.modules.d/00-base.conf:
> > Cannot load modules/mod_http2.so into server: libnghttp2-
> > httpd24.so.14: cannot open shared object file: No such file or
> > directory

You will typically get this error if you try to run the httpd executable 
from outside the SCL environment (i.e. not either under "scl enable 
httpd24" nor from the systemd unit).  Otherwise you should not see this; 
LoadFile tricks to get the libary loaded are definitely not recommended, 
"scl enable" will adjust LD_LIBRARY_PATH so the library can be find.

> However, this was not the cause for the http2 not to work. The actual
> cause was that the SSL module provided by SCL (httpd24-mod_ssl) seems
> to be built against OpenSSL version 1.0.1e which is older than the
> version required (1.0.2) to support ALPN (i.e. to have http/2
> communication with the all the major browsers).

Yes, unfortunately we can't support HTTP/2 with ALPN on the older 

The updated httpd24 collection in testing for RHSCL 3.0 Beta has httpd 
2.4.27 packages which do support ALPN if running on OpenSSL 1.0.2 (i.e. 
RHEL 7.4).  We'd very much welcome testing feedback there if you're able 
to test that out.  Note that recent versions of mod_http2 also require 
switching to the "event" MPM.

Regards, Joe

Joe Orton // Red Hat Core Services

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