private ClusterControllerContainerCluster getDedicatedSharedControllers(ModelElement contentElement,
                                                                                Admin admin,
                                                                                ConfigModelContext context,
                                                                                DeployState deployState,
                                                                                String clusterName) {
            if (admin.getClusterControllers() == null) {
                NodesSpecification spec = NodesSpecification.requiredFromSharedParents(deployState.zone().environment().isProduction() ? 3 : 1,
                                                                                       NodeResources.unspecified(),
                                                                                       contentElement,
                                                                                       context);
                Collection<HostResource> hosts = spec.provision(admin.hostSystem(),
                                                                ClusterSpec.Type.admin,
                                                                ClusterSpec.Id.from(clusterName),
                                                                context.getDeployLogger(),
                                                                true,
                                                                context.clusterInfo().build())
                                                     .keySet();
                admin.setClusterControllers(createClusterControllers(new ClusterControllerCluster(admin, "standalone", deployState),
                                                                     hosts,
                                                                     clusterName,
                                                                     true,
                                                                     context.getDeployState()),
                                            deployState);
            }
            return admin.getClusterControllers();
        }
Returns of memory reserved on a host. Memory is reserved for the jvm if the cluster is combined
config-model/src/main/java/com/yahoo/vespa/model/content/cluster/ContentCluster.java