Updating to JBCS httpd rpms to latest 2.4.51 and moving to jbcs-httpd24-mod_proxy_cluster and its mod_proxy_cluster.conf breaks existing working mod_cluster configurations. These were generally always in the typical /opt/rh/jbcs-httpd24/root/etc/httpd/conf.d/mod_cluster.conf. But with latest 2.4.51 updates, that is moved to /opt/rh/jbcs-httpd24/root/etc/httpd/conf.d/mod_cluster.conf.rpmsave and a default /opt/rh/jbcs-httpd24/root/etc/httpd/conf.d/mod_proxy_cluster.conf is put in its place.

So then mod_cluster no longer functions as expected since the pre-existing config in mod_cluster.conf is dropped by the update.

Quickest solution is likely then to copy the previous mod_cluster.conf.rpmsave to mod_proxy_cluster.conf to restore that config to the new file name:

sudo cp /opt/rh/jbcs-httpd24/root/etc/httpd/conf.d/mod_cluster.conf.rpmsave /opt/rh/jbcs-httpd24/root/etc/httpd/conf.d/mod_proxy_cluster.conf

But this is an undesired step for what should be a seamless rpm update.

A zip install attempt may also be impacted if a 2.4.37 or earlier user copies their configs to the new 2.4.51, carrying over their mod_cluster.conf to then be put in place alongside mod_proxy_cluster.conf for conflicts.