While progressively disabling modules I don't need for my application, I found an issue with apachectl configtest returning Syntax OK, but the restart of httpd failing. When I comment out: LoadModule slotmem_shm_module modules/mod_slotmem_shm.so And do a sudo apachectl configtest I get back "Syntax OK" but when I do a sudo apachectl restart I get back "Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details." Now, neither of those locations gave me anything useful, but when I look at /var/log/httpd/error_log, I get back: [Mon Sep 23 00:16:52.992948 2019] [core:notice] [pid 1467] SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0 [Mon Sep 23 00:16:52.994536 2019] [suexec:notice] [pid 1467] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec) [Mon Sep 23 00:16:53.008462 2019] [lbmethod_heartbeat:notice] [pid 1467] AH02281: Failed to lookup provider 'shm' for 'slotmem'. Maybe you need to load mod_slotmem_shm? [Mon Sep 23 00:16:53.008478 2019] [proxy_balancer:emerg] [pid 1467] AH01177: Failed to lookup provider 'shm' for 'slotmem': is mod_slotmem_shm loaded?? [Mon Sep 23 00:16:53.008485 2019] [:emerg] [pid 1467] AH00020: Configuration Failed, exiting Now I am running (and will need to for my application) proxy_balancer and lbmethod_heartbeat and when I look at the Apache documentation for lbmethod_heartbeat I see the HeartbeatStorage directive offers an alternate location for heartbeat data, SHOULD mod_slotmem_shm not be loaded. I believe apachectl configtest should have returned a syntax error in that mod_slotmem_shm wasn't loaded but there was no HearbeatStorage directive to make up for it.