From your descriptions of the problem it sounds like your server-one which binds to port 8080 doesn't have keycloak-server configured at all - it's using a server group, that uses a different profile than the one you configured.

There are four profiles in the default domain.xml - default, ha, full, and full-ha

If you want your multiple Keycloak instances to run in high availability mode, using a shared Infinispan cache, and a shared database, then that's the most complex of all configurations - you have to setup a standalone database, use "full-ha" profile to configure the datasource with proper database connection url, and configure the distributed Infinispan cache. Also add <subsystem xmlns="urn:jboss:domain:keycloak-server:1.1"> declaration. 

In server-groups section define a new group or reuse existing one, and set its profile to "full-ha", and use "full-ha-sockets" binding group.
In host.xml make sure that server definitions have the proper group set.

Then you also have to copy some configurations.

Assuming you have two servers defined in host.xml - called server-one, and server-two, create a directory:

$WILDFLY_HOME/domain/servers/server-one/configuration
$WILDFLY_HOME/domain/servers/server-two/configuration

Then copy the following configurations from standalone/configuration:

cp $WILDFLY_HOME/standalone/configuration/keycloak-server.json $WILDFLY_HOME/domain/servers/server-one/configuration/
cp -r $WILDFLY_HOME/standalone/configuration/themes $WILDFLY_HOME/domain/servers/server-one/configuration/
cp -r $WILDFLY_HOME/standalone/configuration/providers $WILDFLY_HOME/domain/servers/server-one/configuration/

cp $WILDFLY_HOME/standalone/configuration/keycloak-server.json $WILDFLY_HOME/domain/servers/server-two/configuration/
cp -r $WILDFLY_HOME/standalone/configuration/themes $WILDFLY_HOME/domain/servers/server-two/configuration/
cp -r $WILDFLY_HOME/standalone/configuration/providers $WILDFLY_HOME/domain/servers/server-two/configuration/