Add var to set the jgroups IP per host

This is useful if the default route does not
represent the network you want/need to use for
cluster communication.

roles/keycloak_quarkus/meta/argument_specs.yml

@@ -195,6 +195,10 @@ argument_specs:
                 default: 9000
                 description: "Port of the management interface. Relevant only when something is exposed on the management interface - see the guide for details."
                 type: "int"
+            keycloak_quarkus_jgroups_ip:
+                default: "{{ ansible_default_ipv4.address }}"
+                description: Host jgroups IP.  If changing this variable you must make sure it is always set for all hosts in your cluster.
+                type: "str"
             keycloak_quarkus_jgroups_port:
                 default: 7800
                 description: "jgroups cluster tcp port"