OKD4 installation requires a load balancer and here is an HAProxy config

OKD4 installation LB HAProxy config

global
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    stats socket /var/lib/haproxy/stats

    ssl-default-bind-ciphers PROFILE=SYSTEM
    ssl-default-server-ciphers PROFILE=SYSTEM

defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    timeout connect         10s
    timeout client          1m
    timeout server          1m

listen  stats
    bind *:9000
    mode            http
    log             global
    stats enable
    stats refresh 30s
    stats show-node

frontend openshift-api-server
    bind *:6443
    bind *:443
    default_backend openshift-api-server
    mode tcp
    option tcplog

backend openshift-api-server
    balance source
    mode tcp
    server btstrap 10.0.2.20:6443 check
    server master0 10.0.2.15:6443 check
    server master1 10.0.2.16:6443 check
    server master2 10.0.2.17:6443 check

frontend machine-config-server
    bind *:22623
    default_backend machine-config-server
    mode tcp
    option tcplog

backend machine-config-server
    balance source
    mode tcp
    server btstrap 10.0.2.20:22623 check
    server master0 10.0.2.15:22623 check
    server master1 10.0.2.16:22623 check
    server master2 10.0.2.17:22623 check