@Test
    void testSingleCluster() throws Exception {
        String xml = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n" +
                "<services>\n" +
                "\n" +
                "  <admin version=\"2.0\">\n" +
                "    <adminserver hostalias=\"configserver\" />\n" +
                "    <cluster-controllers>\n" +
                "      <cluster-controller hostalias=\"configserver\">" +
                "      </cluster-controller>" +
                "      <cluster-controller hostalias=\"configserver\"/>" +
                "      <cluster-controller hostalias=\"configserver\"/>" +
                "    </cluster-controllers>\n" +
                "  </admin>\n" +
                "  <content version='1.0' id='bar'>" +
                "     <redundancy>1</redundancy>\n" +
                "     <documents>" +
                "       <document type=\"type1\" mode=\"store-only\"/>\n" +
                "     </documents>\n" +
                "     <group>" +
                "       <node hostalias='node0' distribution-key='0' />" +
                "     </group>" +
                "    <tuning>" +
                "      <cluster-controller>\n" +
                "        <init-progress-time>34567s</init-progress-time>" +
                "        <transition-time>4000ms</transition-time>" +
                "        <stable-state-period>1h</stable-state-period>" +
                "      </cluster-controller>" +
                "    </tuning>" +
                "   </content>" +
                "\n" +
                "</services>";


        VespaModel model = createVespaModel(xml);
        assertTrue(model.getService("admin/cluster-controllers/0").isPresent());

        assertTrue(existsHostsWithClusterControllerConfigId(model));
        assertGroupSize(model, "admin/cluster-controllers/0/components/clustercontroller-bar-configurer", 1);
        for (int i = 0; i < 3; ++i) {
            FleetcontrollerConfig.Builder builder = new FleetcontrollerConfig.Builder();
            model.getConfig(builder, "admin/cluster-controllers/" + i + "/components/clustercontroller-bar-configurer");

            FleetcontrollerConfig cfg = new FleetcontrollerConfig(builder);
            assertEquals(i, cfg.index());
            assertEquals(3, cfg.fleet_controller_count());
            assertEquals(34567000, cfg.init_progress_time());
            assertEquals(4000, cfg.storage_transition_time());
            assertEquals(3600000, cfg.stable_state_time_period());
        }

        assertOnlyNecessaryBundles(model);
    }
Test for creating cluster controllers under the admin tag.
config-model/src/test/java/com/yahoo/vespa/model/admin/ClusterControllerTestCase.java