setting HTTPD_MTM environment variable fails

[nmars]

In investigating a failure of the run_mpm_config_test, I noticed that no matter how I set the HTTPD_MTM environment variable, MTM is still defaulting to prefork.

i.e.:

$ docker run -d -e HTTPD_MPM=event --name httpd rhscl/httpd-24-rhel7
c1b759f93b40ac239a0a22ae246adb6a4f1a273281e84375efbfe9ceebb4234f

$ docker exec -it httpd /usr/bin/bash

bash-4.2$ httpd -V |grep MPM
Server MPM:     prefork

bash-4.2$ cat /etc/httpd/conf.modules.d/00-mpm.conf |grep -v "^#"|grep -v "^$"
LoadModule mpm_prefork_module modules/mod_mpm_prefork.so

bash-4.2$ 

Here's what I see regarding MTM in the logs:

$ docker logs httpd |grep mpm
[Wed Aug 29 14:30:07.720003 2018] [http2:warn] [pid 1] AH10034: The mpm module (prefork.c) is not supported by mod_http2. The mpm determines how things are processed in your server. HTTP/2 has more demands in this regard and the currently selected mpm will just not do. This is an advisory warning. Your server will continue to work, but the HTTP/2 protocol will be inactive.
[Wed Aug 29 14:30:07.724628 2018] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.27 (Red Hat) OpenSSL/1.0.1e-fips configured -- resuming normal operations

[notroj]

Where are you getting rhscl/httpd-24-rhel7 from? The one currently in the public registry has not yet been updated to support HTTPD_MPM AFAIK.