RHEL8 brings HAProxy 1.8 which contains some incompatible changes from the RHEL7 version.
Verified: - Undercloud: [stack@undercloud-0 ~]$ rhos-release -L Installed repositories (rhel-8.0): 15 ceph-4 ceph-osd-4 rhel-8.0 [stack@undercloud-0 ~]$ rpm -qa | grep openstack-tripleo-heat-templates-10.5.1-0.20190701110422.889d4d4.el8ost openstack-tripleo-heat-templates-10.5.1-0.20190701110422.889d4d4.el8ost.noarch - Overcloud: ()[root@controller-0 /]# haproxy -v HA-Proxy version 1.8.15 2018/12/13 Copyright 2000-2018 Willy Tarreau <willy> ()[root@controller-1 /]# haproxy -v HA-Proxy version 1.8.15 2018/12/13 Copyright 2000-2018 Willy Tarreau <willy> ()[root@controller-2 /]# haproxy -v HA-Proxy version 1.8.15 2018/12/13 Copyright 2000-2018 Willy Tarreau <willy>
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2019:2811