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Posted to commits@knox.apache.org by lm...@apache.org on 2017/10/26 14:22:46 UTC

[10/37] knox git commit: KNOX-1014 - Service Discovery and Topology Generation Framework (Phil Zampino via lmccay)

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/b/gateway-discovery-ambari/src/test/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryTest.java
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diff --git a/b/gateway-discovery-ambari/src/test/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryTest.java b/b/gateway-discovery-ambari/src/test/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryTest.java
new file mode 100644
index 0000000..1e5e7b2
--- /dev/null
+++ b/b/gateway-discovery-ambari/src/test/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryTest.java
@@ -0,0 +1,856 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import net.minidev.json.JSONObject;
+import net.minidev.json.JSONValue;
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscovery;
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryConfig;
+import org.easymock.EasyMock;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.*;
+
+
+/**
+ * Test the Ambari ServiceDiscovery implementation.
+ *
+ * N.B. These tests do NOT verify Ambari API responses. They DO validate the Ambari ServiceDiscovery implementation's
+ *      treatment of the responses as they were observed at the time the tests are developed.
+ */
+public class AmbariServiceDiscoveryTest {
+
+    @Test
+    public void testSingleClusterDiscovery() throws Exception {
+        final String discoveryAddress = "http://ambarihost:8080";
+        final String clusterName = "testCluster";
+        ServiceDiscovery sd = new TestAmbariServiceDiscovery(clusterName);
+
+        ServiceDiscoveryConfig sdc = EasyMock.createNiceMock(ServiceDiscoveryConfig.class);
+        EasyMock.expect(sdc.getAddress()).andReturn(discoveryAddress).anyTimes();
+        EasyMock.expect(sdc.getUser()).andReturn(null).anyTimes();
+        EasyMock.replay(sdc);
+
+        ServiceDiscovery.Cluster cluster = sd.discover(sdc, clusterName);
+        assertNotNull(cluster);
+        assertEquals(clusterName, cluster.getName());
+        assertTrue(AmbariCluster.class.isAssignableFrom(cluster.getClass()));
+        assertEquals(6, ((AmbariCluster) cluster).getComponents().size());
+
+//        printServiceURLs(cluster);
+    }
+
+
+    @Test
+    public void testBulkClusterDiscovery() throws Exception {
+        final String discoveryAddress = "http://ambarihost:8080";
+        final String clusterName = "anotherCluster";
+        ServiceDiscovery sd = new TestAmbariServiceDiscovery(clusterName);
+
+        ServiceDiscoveryConfig sdc = EasyMock.createNiceMock(ServiceDiscoveryConfig.class);
+        EasyMock.expect(sdc.getAddress()).andReturn(discoveryAddress).anyTimes();
+        EasyMock.expect(sdc.getUser()).andReturn(null).anyTimes();
+        EasyMock.replay(sdc);
+
+        Map<String, ServiceDiscovery.Cluster> clusters = sd.discover(sdc);
+        assertNotNull(clusters);
+        assertEquals(1, clusters.size());
+        ServiceDiscovery.Cluster cluster = clusters.get(clusterName);
+        assertNotNull(cluster);
+        assertEquals(clusterName, cluster.getName());
+        assertTrue(AmbariCluster.class.isAssignableFrom(cluster.getClass()));
+        assertEquals(6, ((AmbariCluster) cluster).getComponents().size());
+
+//        printServiceURLs(cluster, "NAMENODE", "WEBHCAT", "OOZIE", "RESOURCEMANAGER");
+    }
+
+
+    private static void printServiceURLs(ServiceDiscovery.Cluster cluster) {
+        final String[] services = new String[]{"NAMENODE",
+                                               "JOBTRACKER",
+                                               "WEBHDFS",
+                                               "WEBHCAT",
+                                               "OOZIE",
+                                               "WEBHBASE",
+                                               "HIVE",
+                                               "RESOURCEMANAGER"};
+        printServiceURLs(cluster, services);
+    }
+
+
+    private static void printServiceURLs(ServiceDiscovery.Cluster cluster, String...services) {
+        for (String name : services) {
+            StringBuilder sb = new StringBuilder();
+            List<String> urls = cluster.getServiceURLs(name);
+            if (urls != null && !urls.isEmpty()) {
+                for (String url : urls) {
+                    sb.append(url);
+                    sb.append(" ");
+                }
+            }
+            System.out.println(String.format("%18s: %s", name, sb.toString()));
+        }
+    }
+
+
+    /**
+     * ServiceDiscovery implementation derived from AmbariServiceDiscovery, so the invokeREST method can be overridden
+     * to eliminate the need to perform actual HTTP interactions with a real Ambari endpoint.
+     */
+    private static final class TestAmbariServiceDiscovery extends AmbariServiceDiscovery {
+
+        final static String CLUSTER_PLACEHOLDER = "CLUSTER_NAME";
+
+        private Map<String, JSONObject> cannedResponses = new HashMap<>();
+
+        TestAmbariServiceDiscovery(String clusterName) {
+            cannedResponses.put(AmbariServiceDiscovery.AMBARI_CLUSTERS_URI,
+                                (JSONObject) JSONValue.parse(CLUSTERS_JSON_TEMPLATE.replaceAll(CLUSTER_PLACEHOLDER,
+                                                                                               clusterName)));
+
+            cannedResponses.put(String.format(AmbariServiceDiscovery.AMBARI_HOSTROLES_URI, clusterName),
+                                (JSONObject) JSONValue.parse(HOSTROLES_JSON_TEMPLATE.replaceAll(CLUSTER_PLACEHOLDER,
+                                                                                                clusterName)));
+
+            cannedResponses.put(String.format(AmbariServiceDiscovery.AMBARI_SERVICECONFIGS_URI, clusterName),
+                                (JSONObject) JSONValue.parse(SERVICECONFIGS_JSON_TEMPLATE.replaceAll(CLUSTER_PLACEHOLDER,
+                                                                                                     clusterName)));
+        }
+
+        @Override
+        protected JSONObject invokeREST(String url, String username, String passwordAlias) {
+            return cannedResponses.get(url.substring(url.indexOf("/api")));
+        }
+    }
+
+
+    ////////////////////////////////////////////////////////////////////////
+    //  JSON response templates, based on actual response content excerpts
+    ////////////////////////////////////////////////////////////////////////
+
+    private static final String CLUSTERS_JSON_TEMPLATE =
+    "{\n" +
+    "  \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters\",\n" +
+    "  \"items\" : [\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"Clusters\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"version\" : \"HDP-2.6\"\n" +
+    "      }\n" +
+    "    }\n" +
+    "  ]" +
+    "}";
+
+
+    private static final String HOSTROLES_JSON_TEMPLATE =
+    "{\n" +
+    "  \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services?fields=components/host_components/HostRoles\",\n" +
+    "  \"items\" : [\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/AMBARI_METRICS\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"AMBARI_METRICS\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/AMBARI_METRICS/components/METRICS_COLLECTOR\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"METRICS_COLLECTOR\",\n" +
+    "            \"service_name\" : \"AMBARI_METRICS\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6403.ambari.apache.org/host_components/METRICS_COLLECTOR\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"METRICS_COLLECTOR\",\n" +
+    "                \"host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"AMBARI_METRICS\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HBASE/components/HBASE_MASTER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"HBASE_MASTER\",\n" +
+    "            \"service_name\" : \"HBASE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6401.ambari.apache.org/host_components/HBASE_MASTER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"HBASE_MASTER\",\n" +
+    "                \"host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HBASE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HDFS\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"HDFS\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HDFS/components/NAMENODE\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"NAMENODE\",\n" +
+    "            \"service_name\" : \"HDFS\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6401.ambari.apache.org/host_components/NAMENODE\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"NAMENODE\",\n" +
+    "                \"host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HDFS\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HDFS/components/SECONDARY_NAMENODE\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"SECONDARY_NAMENODE\",\n" +
+    "            \"service_name\" : \"HDFS\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/SECONDARY_NAMENODE\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"SECONDARY_NAMENODE\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HDFS\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HIVE\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"HIVE\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HIVE/components/HCAT\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"HCAT\",\n" +
+    "            \"service_name\" : \"HIVE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6403.ambari.apache.org/host_components/HCAT\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"HCAT\",\n" +
+    "                \"host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HIVE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HIVE/components/HIVE_METASTORE\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"HIVE_METASTORE\",\n" +
+    "            \"service_name\" : \"HIVE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/HIVE_METASTORE\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"HIVE_METASTORE\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HIVE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HIVE/components/HIVE_SERVER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"HIVE_SERVER\",\n" +
+    "            \"service_name\" : \"HIVE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/HIVE_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"HIVE_SERVER\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HIVE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/HIVE/components/WEBHCAT_SERVER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"WEBHCAT_SERVER\",\n" +
+    "            \"service_name\" : \"HIVE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/WEBHCAT_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"WEBHCAT_SERVER\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"HIVE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\",\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/OOZIE\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"OOZIE\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/OOZIE/components/OOZIE_SERVER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"OOZIE_SERVER\",\n" +
+    "            \"service_name\" : \"OOZIE\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/OOZIE_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"OOZIE_SERVER\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"OOZIE\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/YARN\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"YARN\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/YARN/components/APP_TIMELINE_SERVER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"APP_TIMELINE_SERVER\",\n" +
+    "            \"service_name\" : \"YARN\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/APP_TIMELINE_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"APP_TIMELINE_SERVER\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"YARN\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/YARN/components/NODEMANAGER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"NODEMANAGER\",\n" +
+    "            \"service_name\" : \"YARN\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6403.ambari.apache.org/host_components/NODEMANAGER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"NODEMANAGER\",\n" +
+    "                \"host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"YARN\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/YARN/components/RESOURCEMANAGER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"RESOURCEMANAGER\",\n" +
+    "            \"service_name\" : \"YARN\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/RESOURCEMANAGER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"RESOURCEMANAGER\",\n" +
+    "                \"ha_state\" : \"ACTIVE\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"YARN\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/ZOOKEEPER\",\n" +
+    "      \"ServiceInfo\" : {\n" +
+    "        \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "        \"service_name\" : \"ZOOKEEPER\"\n" +
+    "      },\n" +
+    "      \"components\" : [\n" +
+    "        {\n" +
+    "          \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/services/ZOOKEEPER/components/ZOOKEEPER_SERVER\",\n" +
+    "          \"ServiceComponentInfo\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"component_name\" : \"ZOOKEEPER_SERVER\",\n" +
+    "            \"service_name\" : \"ZOOKEEPER\"\n" +
+    "          },\n" +
+    "          \"host_components\" : [\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6401.ambari.apache.org/host_components/ZOOKEEPER_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"ZOOKEEPER_SERVER\",\n" +
+    "                \"host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6401.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"ZOOKEEPER\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            },\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6402.ambari.apache.org/host_components/ZOOKEEPER_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"ZOOKEEPER_SERVER\",\n" +
+    "                \"host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6402.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"ZOOKEEPER\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            },\n" +
+    "            {\n" +
+    "              \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/hosts/c6403.ambari.apache.org/host_components/ZOOKEEPER_SERVER\",\n" +
+    "              \"HostRoles\" : {\n" +
+    "                \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "                \"component_name\" : \"ZOOKEEPER_SERVER\",\n" +
+    "                \"host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"public_host_name\" : \"c6403.ambari.apache.org\",\n" +
+    "                \"service_name\" : \"ZOOKEEPER\",\n" +
+    "                \"stack_id\" : \"HDP-2.6\"\n" +
+    "              }\n" +
+    "            }\n" +
+    "          ]\n" +
+    "        }\n" +
+    "      ]\n" +
+    "    }\n" +
+    "  ]\n" +
+    "}\n";
+
+
+    private static final String SERVICECONFIGS_JSON_TEMPLATE =
+    "{\n" +
+    "  \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?is_current=true\",\n" +
+    "  \"items\" : [\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=HBASE&service_config_version=1\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hbase-site\",\n" +
+    "          \"tag\" : \"version1503410563715\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hbase.master.info.bindAddress\" : \"0.0.0.0\",\n" +
+    "            \"hbase.master.info.port\" : \"16010\",\n" +
+    "            \"hbase.master.port\" : \"16000\",\n" +
+    "            \"hbase.regionserver.info.port\" : \"16030\",\n" +
+    "            \"hbase.regionserver.port\" : \"16020\",\n" +
+    "            \"hbase.zookeeper.property.clientPort\" : \"2181\",\n" +
+    "            \"hbase.zookeeper.quorum\" : \"c6403.ambari.apache.org,c6402.ambari.apache.org,c6401.ambari.apache.org\",\n" +
+    "            \"hbase.zookeeper.useMulti\" : \"true\",\n" +
+    "            \"zookeeper.znode.parent\" : \"/hbase-unsecure\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        },\n" +
+    "      ],\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 1,\n" +
+    "      \"service_config_version_note\" : \"Initial configurations for HBase\",\n" +
+    "      \"service_name\" : \"HBASE\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=HDFS&service_config_version=2\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hdfs-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"dfs.cluster.administrators\" : \" hdfs\",\n" +
+    "            \"dfs.datanode.address\" : \"0.0.0.0:50010\",\n" +
+    "            \"dfs.datanode.http.address\" : \"0.0.0.0:50075\",\n" +
+    "            \"dfs.datanode.https.address\" : \"0.0.0.0:50475\",\n" +
+    "            \"dfs.datanode.ipc.address\" : \"0.0.0.0:8010\",\n" +
+    "            \"dfs.http.policy\" : \"HTTP_ONLY\",\n" +
+    "            \"dfs.https.port\" : \"50470\",\n" +
+    "            \"dfs.journalnode.http-address\" : \"0.0.0.0:8480\",\n" +
+    "            \"dfs.journalnode.https-address\" : \"0.0.0.0:8481\",\n" +
+    "            \"dfs.namenode.http-address\" : \"c6401.ambari.apache.org:50070\",\n" +
+    "            \"dfs.namenode.https-address\" : \"c6401.ambari.apache.org:50470\",\n" +
+    "            \"dfs.namenode.rpc-address\" : \"c6401.ambari.apache.org:8020\",\n" +
+    "            \"dfs.namenode.secondary.http-address\" : \"c6402.ambari.apache.org:50090\",\n" +
+    "            \"dfs.webhdfs.enabled\" : \"true\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : {\n" +
+    "            \"final\" : {\n" +
+    "              \"dfs.webhdfs.enabled\" : \"true\",\n" +
+    "              \"dfs.namenode.http-address\" : \"true\",\n" +
+    "              \"dfs.support.append\" : \"true\",\n" +
+    "              \"dfs.namenode.name.dir\" : \"true\",\n" +
+    "              \"dfs.datanode.failed.volumes.tolerated\" : \"true\",\n" +
+    "              \"dfs.datanode.data.dir\" : \"true\"\n" +
+    "            }\n" +
+    "          }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"core-site\",\n" +
+    "          \"tag\" : \"version1502131215159\",\n" +
+    "          \"version\" : 2,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hadoop.http.authentication.simple.anonymous.allowed\" : \"true\",\n" +
+    "            \"net.topology.script.file.name\" : \"/etc/hadoop/conf/topology_script.py\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : {\n" +
+    "            \"final\" : {\n" +
+    "              \"fs.defaultFS\" : \"true\"\n" +
+    "            }\n" +
+    "          }\n" +
+    "        }\n" +
+    "      ],\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 2,\n" +
+    "      \"service_config_version_note\" : \"knox trusted proxy support\",\n" +
+    "      \"service_name\" : \"HDFS\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=HIVE&service_config_version=3\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hive-env\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hive_security_authorization\" : \"None\",\n" +
+    "            \"webhcat_user\" : \"hcat\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hiveserver2-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hive.metastore.metrics.enabled\" : \"true\",\n" +
+    "            \"hive.security.authorization.enabled\" : \"false\",\n" +
+    "            \"hive.service.metrics.hadoop2.component\" : \"hiveserver2\",\n" +
+    "            \"hive.service.metrics.reporter\" : \"HADOOP2\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hive-interactive-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hive.server2.enable.doAs\" : \"false\",\n" +
+    "            \"hive.server2.tez.default.queues\" : \"default\",\n" +
+    "            \"hive.server2.tez.initialize.default.sessions\" : \"true\",\n" +
+    "            \"hive.server2.tez.sessions.custom.queue.allowed\" : \"ignore\",\n" +
+    "            \"hive.server2.tez.sessions.per.default.queue\" : \"1\",\n" +
+    "            \"hive.server2.tez.sessions.restricted.configs\" : \"hive.execution.mode,hive.execution.engine\",\n" +
+    "            \"hive.server2.thrift.http.port\" : \"10501\",\n" +
+    "            \"hive.server2.thrift.port\" : \"10500\",\n" +
+    "            \"hive.server2.webui.port\" : \"10502\",\n" +
+    "            \"hive.server2.webui.use.ssl\" : \"false\",\n" +
+    "            \"hive.server2.zookeeper.namespace\" : \"hiveserver2-hive2\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"tez-interactive-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"tez.am.am-rm.heartbeat.interval-ms.max\" : \"10000\",\n" +
+    "            \"tez.am.client.heartbeat.poll.interval.millis\" : \"6000\",\n" +
+    "            \"tez.am.client.heartbeat.timeout.secs\" : \"90\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"hive-site\",\n" +
+    "          \"tag\" : \"version1502130841736\",\n" +
+    "          \"version\" : 2,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hive.metastore.sasl.enabled\" : \"false\",\n" +
+    "            \"hive.metastore.server.max.threads\" : \"100000\",\n" +
+    "            \"hive.metastore.uris\" : \"thrift://c6402.ambari.apache.org:9083\",\n" +
+    "            \"hive.server2.allow.user.substitution\" : \"true\",\n" +
+    "            \"hive.server2.authentication\" : \"NONE\",\n" +
+    "            \"hive.server2.authentication.spnego.keytab\" : \"HTTP/_HOST@EXAMPLE.COM\",\n" +
+    "            \"hive.server2.authentication.spnego.principal\" : \"/etc/security/keytabs/spnego.service.keytab\",\n" +
+    "            \"hive.server2.enable.doAs\" : \"true\",\n" +
+    "            \"hive.server2.support.dynamic.service.discovery\" : \"true\",\n" +
+    "            \"hive.server2.thrift.http.path\" : \"cliservice\",\n" +
+    "            \"hive.server2.thrift.http.port\" : \"10001\",\n" +
+    "            \"hive.server2.thrift.max.worker.threads\" : \"500\",\n" +
+    "            \"hive.server2.thrift.port\" : \"10000\",\n" +
+    "            \"hive.server2.thrift.sasl.qop\" : \"auth\",\n" +
+    "            \"hive.server2.transport.mode\" : \"http\",\n" +
+    "            \"hive.server2.use.SSL\" : \"false\",\n" +
+    "            \"hive.server2.zookeeper.namespace\" : \"hiveserver2\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : {\n" +
+    "            \"hidden\" : {\n" +
+    "              \"javax.jdo.option.ConnectionPassword\" : \"HIVE_CLIENT,WEBHCAT_SERVER,HCAT,CONFIG_DOWNLOAD\"\n" +
+    "            }\n" +
+    "          }\n" +
+    "        },\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"webhcat-site\",\n" +
+    "          \"tag\" : \"version1502131111746\",\n" +
+    "          \"version\" : 2,\n" +
+    "          \"properties\" : {\n" +
+    "            \"templeton.port\" : \"50111\",\n" +
+    "            \"templeton.zookeeper.hosts\" : \"c6403.ambari.apache.org:2181,c6401.ambari.apache.org:2181,c6402.ambari.apache.org:2181\",\n" +
+    "            \"webhcat.proxyuser.knox.groups\" : \"users\",\n" +
+    "            \"webhcat.proxyuser.knox.hosts\" : \"*\",\n" +
+    "            \"webhcat.proxyuser.root.groups\" : \"*\",\n" +
+    "            \"webhcat.proxyuser.root.hosts\" : \"c6401.ambari.apache.org\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        }\n" +
+    "      ],\n" +
+    "      \"createtime\" : 1502131110745,\n" +
+    "      \"group_id\" : -1,\n" +
+    "      \"group_name\" : \"Default\",\n" +
+    "      \"hosts\" : [ ],\n" +
+    "      \"is_cluster_compatible\" : true,\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 3,\n" +
+    "      \"service_config_version_note\" : \"knox trusted proxy support\",\n" +
+    "      \"service_name\" : \"HIVE\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=OOZIE&service_config_version=3\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"oozie-site\",\n" +
+    "          \"tag\" : \"version1502131137103\",\n" +
+    "          \"version\" : 3,\n" +
+    "          \"properties\" : {\n" +
+    "            \"oozie.base.url\" : \"http://c6402.ambari.apache.org:11000/oozie\",\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        }\n" +
+    "      ],\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 3,\n" +
+    "      \"service_name\" : \"OOZIE\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=TEZ&service_config_version=1\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"tez-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"tez.use.cluster.hadoop-libs\" : \"false\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        }\n" +
+    "      ],\n" +
+    "      \"createtime\" : 1502122253525,\n" +
+    "      \"group_id\" : -1,\n" +
+    "      \"group_name\" : \"Default\",\n" +
+    "      \"hosts\" : [ ],\n" +
+    "      \"is_cluster_compatible\" : true,\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 1,\n" +
+    "      \"service_config_version_note\" : \"Initial configurations for Tez\",\n" +
+    "      \"service_name\" : \"TEZ\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    },\n" +
+    "    {\n" +
+    "      \"href\" : \"http://c6401.ambari.apache.org:8080/api/v1/clusters/"+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"/configurations/service_config_versions?service_name=YARN&service_config_version=1\",\n" +
+    "      \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "      \"configurations\" : [\n" +
+    "        {\n" +
+    "          \"Config\" : {\n" +
+    "            \"cluster_name\" : \""+TestAmbariServiceDiscovery.CLUSTER_PLACEHOLDER+"\",\n" +
+    "            \"stack_id\" : \"HDP-2.6\"\n" +
+    "          },\n" +
+    "          \"type\" : \"yarn-site\",\n" +
+    "          \"tag\" : \"version1\",\n" +
+    "          \"version\" : 1,\n" +
+    "          \"properties\" : {\n" +
+    "            \"hadoop.registry.rm.enabled\" : \"true\",\n" +
+    "            \"hadoop.registry.zk.quorum\" : \"c6403.ambari.apache.org:2181,c6401.ambari.apache.org:2181,c6402.ambari.apache.org:2181\",\n" +
+    "            \"yarn.acl.enable\" : \"false\",\n" +
+    "            \"yarn.http.policy\" : \"HTTP_ONLY\",\n" +
+    "            \"yarn.nodemanager.address\" : \"0.0.0.0:45454\",\n" +
+    "            \"yarn.nodemanager.bind-host\" : \"0.0.0.0\",\n" +
+    "            \"yarn.resourcemanager.address\" : \"c6402.ambari.apache.org:8050\",\n" +
+    "            \"yarn.resourcemanager.admin.address\" : \"c6402.ambari.apache.org:8141\",\n" +
+    "            \"yarn.resourcemanager.ha.enabled\" : \"false\",\n" +
+    "            \"yarn.resourcemanager.hostname\" : \"c6402.ambari.apache.org\",\n" +
+    "            \"yarn.resourcemanager.resource-tracker.address\" : \"c6402.ambari.apache.org:8025\",\n" +
+    "            \"yarn.resourcemanager.scheduler.address\" : \"c6402.ambari.apache.org:8030\",\n" +
+    "            \"yarn.resourcemanager.webapp.address\" : \"c6402.ambari.apache.org:8088\",\n" +
+    "            \"yarn.resourcemanager.webapp.delegation-token-auth-filter.enabled\" : \"false\",\n" +
+    "            \"yarn.resourcemanager.webapp.https.address\" : \"c6402.ambari.apache.org:8090\",\n" +
+    "            \"yarn.resourcemanager.zk-address\" : \"c6403.ambari.apache.org:2181,c6401.ambari.apache.org:2181,c6402.ambari.apache.org:2181\"\n" +
+    "          },\n" +
+    "          \"properties_attributes\" : { }\n" +
+    "        }\n" +
+    "      ],\n" +
+    "      \"is_current\" : true,\n" +
+    "      \"service_config_version\" : 1,\n" +
+    "      \"service_name\" : \"YARN\",\n" +
+    "      \"stack_id\" : \"HDP-2.6\",\n" +
+    "      \"user\" : \"admin\"\n" +
+    "    }\n" +
+    "  ]\n" +
+    "}";
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/b/gateway-release/home/conf/descriptors/README
----------------------------------------------------------------------
diff --git a/b/gateway-release/home/conf/descriptors/README b/b/gateway-release/home/conf/descriptors/README
new file mode 100644
index 0000000..a2e5226
--- /dev/null
+++ b/b/gateway-release/home/conf/descriptors/README
@@ -0,0 +1 @@
+THIS DIRECTORY IS WHERE SIMPLE TOPOLOGY DESCRIPTORS CAN BE PLACED
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/b/gateway-release/home/conf/shared-providers/README
----------------------------------------------------------------------
diff --git a/b/gateway-release/home/conf/shared-providers/README b/b/gateway-release/home/conf/shared-providers/README
new file mode 100644
index 0000000..44d12a3
--- /dev/null
+++ b/b/gateway-release/home/conf/shared-providers/README
@@ -0,0 +1 @@
+THIS DIRECTORY IS WHERE SHARED PROVIDER CONFIGURATIONS CAN BE PLACED
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/pom.xml
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/pom.xml b/gateway-discovery-ambari/pom.xml
new file mode 100644
index 0000000..924e89c
--- /dev/null
+++ b/gateway-discovery-ambari/pom.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.apache.knox</groupId>
+        <artifactId>gateway</artifactId>
+        <version>0.14.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>gateway-discovery-ambari</artifactId>
+
+    <name>gateway-discovery-ambari</name>
+    <description>The extension to the gateway for service discovery using Apache Ambari.</description>
+
+    <licenses>
+        <license>
+            <name>The Apache Software License, Version 2.0</name>
+            <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
+            <distribution>repo</distribution>
+        </license>
+    </licenses>
+
+    <dependencies>
+        <dependency>
+            <groupId>${gateway-group}</groupId>
+            <artifactId>gateway-spi</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>${gateway-group}</groupId>
+            <artifactId>gateway-test-utils</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.easymock</groupId>
+            <artifactId>easymock</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+
+</project>

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariCluster.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariCluster.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariCluster.java
new file mode 100644
index 0000000..6eaabd3
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariCluster.java
@@ -0,0 +1,114 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscovery;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+class AmbariCluster implements ServiceDiscovery.Cluster {
+
+    private String name = null;
+
+    private AmbariServiceURLCreator urlCreator = new AmbariServiceURLCreator();
+
+    private Map<String, Map<String, ServiceConfiguration>> serviceConfigurations = new HashMap<>();
+
+    private Map<String, AmbariComponent> components = null;
+
+
+    AmbariCluster(String name) {
+        this.name = name;
+        components = new HashMap<String, AmbariComponent>();
+    }
+
+    void addServiceConfiguration(String serviceName, String configurationType, ServiceConfiguration serviceConfig) {
+        if (!serviceConfigurations.keySet().contains(serviceName)) {
+            serviceConfigurations.put(serviceName, new HashMap<String, ServiceConfiguration>());
+        }
+        serviceConfigurations.get(serviceName).put(configurationType, serviceConfig);
+    }
+
+
+    void addComponent(AmbariComponent component) {
+        components.put(component.getName(), component);
+    }
+
+
+    ServiceConfiguration getServiceConfiguration(String serviceName, String configurationType) {
+        ServiceConfiguration sc = null;
+        Map<String, ServiceConfiguration> configs = serviceConfigurations.get(serviceName);
+        if (configs != null) {
+            sc = configs.get(configurationType);
+        }
+        return sc;
+    }
+
+
+    Map<String, AmbariComponent> getComponents() {
+        return components;
+    }
+
+
+    AmbariComponent getComponent(String name) {
+        return components.get(name);
+    }
+
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+
+    @Override
+    public List<String> getServiceURLs(String serviceName) {
+        List<String> urls = new ArrayList<>();
+        urls.addAll(urlCreator.create(this, serviceName));
+        return urls;
+    }
+
+
+    static class ServiceConfiguration {
+
+        private String type;
+        private String version;
+        private Map<String, String> props;
+
+        ServiceConfiguration(String type, String version, Map<String, String> properties) {
+            this.type = type;
+            this.version = version;
+            this.props = properties;
+        }
+
+        public String getVersion() {
+            return version;
+        }
+
+        public String getType() {
+            return type;
+        }
+
+        public Map<String, String> getProperties() {
+            return props;
+        }
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariComponent.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariComponent.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariComponent.java
new file mode 100644
index 0000000..55257fb
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariComponent.java
@@ -0,0 +1,76 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import java.util.List;
+import java.util.Map;
+
+class AmbariComponent {
+
+    private String clusterName = null;
+    private String serviceName = null;
+    private String name        = null;
+    private String version     = null;
+
+    private List<String> hostNames = null;
+
+    private Map<String, String> properties = null;
+
+    AmbariComponent(String              name,
+                    String              version,
+                    String              cluster,
+                    String              service,
+                    List<String>        hostNames,
+                    Map<String, String> properties) {
+        this.name = name;
+        this.serviceName = service;
+        this.clusterName = cluster;
+        this.version = version;
+        this.hostNames = hostNames;
+        this.properties = properties;
+    }
+
+    public String getVersion() {
+        return version;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getServiceName() {
+        return serviceName;
+    }
+
+    public String getClusterName() {
+        return clusterName;
+    }
+
+    public List<String> getHostNames() {
+        return hostNames;
+    }
+
+    public Map<String, String> getConfigProperties() {
+        return properties;
+    }
+
+    public String getConfigProperty(String propertyName) {
+        return properties.get(propertyName);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscovery.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscovery.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscovery.java
new file mode 100644
index 0000000..34f20a7
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscovery.java
@@ -0,0 +1,291 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import net.minidev.json.JSONArray;
+import net.minidev.json.JSONObject;
+import net.minidev.json.JSONValue;
+import org.apache.hadoop.gateway.config.ConfigurationException;
+import org.apache.hadoop.gateway.i18n.messages.MessagesFactory;
+import org.apache.hadoop.gateway.services.security.AliasService;
+import org.apache.hadoop.gateway.services.security.AliasServiceException;
+import org.apache.hadoop.gateway.topology.discovery.GatewayService;
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscovery;
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryConfig;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpStatus;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.message.BasicHeader;
+import org.apache.http.util.EntityUtils;
+
+import java.io.IOException;
+import java.util.*;
+
+
+class AmbariServiceDiscovery implements ServiceDiscovery {
+
+    static final String TYPE = "AMBARI";
+
+    static final String AMBARI_CLUSTERS_URI = "/api/v1/clusters";
+
+    static final String AMBARI_HOSTROLES_URI =
+                                       AMBARI_CLUSTERS_URI + "/%s/services?fields=components/host_components/HostRoles";
+
+    static final String AMBARI_SERVICECONFIGS_URI =
+            AMBARI_CLUSTERS_URI + "/%s/configurations/service_config_versions?is_current=true";
+
+    // Map of component names to service configuration types
+    private static Map<String, String> componentServiceConfigs = new HashMap<>();
+    static {
+        componentServiceConfigs.put("NAMENODE", "hdfs-site");
+        componentServiceConfigs.put("RESOURCEMANAGER", "yarn-site");
+        componentServiceConfigs.put("OOZIE_SERVER", "oozie-site");
+        componentServiceConfigs.put("HIVE_SERVER", "hive-site");
+        componentServiceConfigs.put("WEBHCAT_SERVER", "webhcat-site");
+        componentServiceConfigs.put("HBASE_MASTER", "hbase-site");
+    } // TODO: Are there other service components, for which the endpoints can be discovered via Ambari?
+
+    private static final String DEFAULT_USER_ALIAS = "ambari.discovery.user";
+    private static final String DEFAULT_PWD_ALIAS  = "ambari.discovery.password";
+
+    private static AmbariServiceURLCreator urlCreator = new AmbariServiceURLCreator();
+
+    private AmbariServiceDiscoveryMessages log = MessagesFactory.get(AmbariServiceDiscoveryMessages.class);
+
+    @GatewayService
+    private AliasService aliasService;
+
+    private CloseableHttpClient httpClient = null;
+
+    private Map<String, Map<String, String>> serviceConfiguration = new HashMap<>();
+
+
+    AmbariServiceDiscovery() {
+        httpClient = org.apache.http.impl.client.HttpClients.createDefault();
+    }
+
+
+    @Override
+    public String getType() {
+        return TYPE;
+    }
+
+
+    @Override
+    public Map<String, Cluster> discover(ServiceDiscoveryConfig config) {
+        Map<String, Cluster> clusters = new HashMap<String, Cluster>();
+
+        String discoveryAddress = config.getAddress();
+
+        // Invoke Ambari REST API to discover the available clusters
+        String clustersDiscoveryURL = String.format("%s" + AMBARI_CLUSTERS_URI, discoveryAddress);
+
+        JSONObject json = invokeREST(clustersDiscoveryURL, config.getUser(), config.getPasswordAlias());
+
+        // Parse the cluster names from the response, and perform the cluster discovery
+        JSONArray clusterItems = (JSONArray) json.get("items");
+        for (Object clusterItem : clusterItems) {
+            String clusterName = (String) ((JSONObject)((JSONObject) clusterItem).get("Clusters")).get("cluster_name");
+            try {
+                Cluster c = discover(config, clusterName);
+                clusters.put(clusterName, c);
+            } catch (Exception e) {
+                log.clusterDiscoveryError(clusterName, e);
+            }
+        }
+
+        return clusters;
+    }
+
+
+    @Override
+    public Cluster discover(ServiceDiscoveryConfig config, String clusterName) {
+        AmbariCluster cluster = new AmbariCluster(clusterName);
+
+        Map<String, String> serviceComponents = new HashMap<>();
+
+        String discoveryAddress = config.getAddress();
+        String discoveryUser = config.getUser();
+        String discoveryPwdAlias = config.getPasswordAlias();
+
+        Map<String, List<String>> componentHostNames = new HashMap<>();
+        String hostRolesURL = String.format("%s" + AMBARI_HOSTROLES_URI, discoveryAddress, clusterName);
+        JSONObject hostRolesJSON = invokeREST(hostRolesURL, discoveryUser, discoveryPwdAlias);
+        if (hostRolesJSON != null) {
+            // Process the host roles JSON
+            JSONArray items = (JSONArray) hostRolesJSON.get("items");
+            for (Object obj : items) {
+                JSONArray components = (JSONArray) ((JSONObject) obj).get("components");
+                for (Object component : components) {
+                    JSONArray hostComponents = (JSONArray) ((JSONObject) component).get("host_components");
+                    for (Object hostComponent : hostComponents) {
+                        JSONObject hostRoles = (JSONObject) ((JSONObject) hostComponent).get("HostRoles");
+                        String serviceName = (String) hostRoles.get("service_name");
+                        String componentName = (String) hostRoles.get("component_name");
+
+                        serviceComponents.put(componentName, serviceName);
+
+//                    String hostName = (String) hostRoles.get("host_name");
+                        String hostName = (String) hostRoles.get("public_host_name"); // Assuming public host name is most applicable
+                        log.discoveredServiceHost(serviceName, hostName);
+                        if (!componentHostNames.containsKey(componentName)) {
+                            componentHostNames.put(componentName, new ArrayList<String>());
+                        }
+                        componentHostNames.get(componentName).add(hostName);
+                    }
+                }
+            }
+        }
+
+        Map<String, Map<String, AmbariCluster.ServiceConfiguration>> serviceConfigurations =
+                                                 new HashMap<String, Map<String, AmbariCluster.ServiceConfiguration>>();
+        String serviceConfigsURL = String.format("%s" + AMBARI_SERVICECONFIGS_URI, discoveryAddress, clusterName);
+        JSONObject serviceConfigsJSON = invokeREST(serviceConfigsURL, discoveryUser, discoveryPwdAlias);
+        if (serviceConfigsJSON != null) {
+            // Process the service configurations
+            JSONArray serviceConfigs = (JSONArray) serviceConfigsJSON.get("items");
+            for (Object serviceConfig : serviceConfigs) {
+                String serviceName = (String) ((JSONObject) serviceConfig).get("service_name");
+                JSONArray configurations = (JSONArray) ((JSONObject) serviceConfig).get("configurations");
+                for (Object configuration : configurations) {
+                    String configType = (String) ((JSONObject) configuration).get("type");
+                    String configVersion = String.valueOf(((JSONObject) configuration).get("version"));
+
+                    Map<String, String> configProps = new HashMap<String, String>();
+                    JSONObject configProperties = (JSONObject) ((JSONObject) configuration).get("properties");
+                    for (String propertyName : configProperties.keySet()) {
+                        configProps.put(propertyName, String.valueOf(((JSONObject) configProperties).get(propertyName)));
+                    }
+                    if (!serviceConfigurations.containsKey(serviceName)) {
+                        serviceConfigurations.put(serviceName, new HashMap<String, AmbariCluster.ServiceConfiguration>());
+                    }
+                    serviceConfigurations.get(serviceName).put(configType, new AmbariCluster.ServiceConfiguration(configType, configVersion, configProps));
+                    cluster.addServiceConfiguration(serviceName, configType, new AmbariCluster.ServiceConfiguration(configType, configVersion, configProps));
+                }
+            }
+        }
+
+        // Construct the AmbariCluster model
+        for (String componentName : serviceComponents.keySet()) {
+            String serviceName = serviceComponents.get(componentName);
+            List<String> hostNames = componentHostNames.get(componentName);
+
+            Map<String, AmbariCluster.ServiceConfiguration> configs = serviceConfigurations.get(serviceName);
+            String configType = componentServiceConfigs.get(componentName);
+            if (configType != null) {
+                AmbariCluster.ServiceConfiguration svcConfig = configs.get(configType);
+                AmbariComponent c = new AmbariComponent(componentName,
+                                                        svcConfig.getVersion(),
+                                                        clusterName,
+                                                        serviceName,
+                                                        hostNames,
+                                                        svcConfig.getProperties());
+                cluster.addComponent(c);
+            }
+        }
+
+        return cluster;
+    }
+
+
+    protected JSONObject invokeREST(String url, String username, String passwordAlias) {
+        JSONObject result = null;
+
+        CloseableHttpResponse response = null;
+        try {
+            HttpGet request = new HttpGet(url);
+
+            // If no configured username, then use default username alias
+            String password = null;
+            if (username == null) {
+                if (aliasService != null) {
+                    try {
+                        char[] defaultUser = aliasService.getPasswordFromAliasForGateway(DEFAULT_USER_ALIAS);
+                        if (defaultUser != null) {
+                            username = new String(defaultUser);
+                        }
+                    } catch (AliasServiceException e) {
+                        log.aliasServiceUserError(DEFAULT_USER_ALIAS, e.getLocalizedMessage());
+                    }
+                }
+
+                // If username is still null
+                if (username == null) {
+                    log.aliasServiceUserNotFound();
+                    throw new ConfigurationException("No username is configured for Ambari service discovery.");
+                }
+            }
+
+            if (aliasService != null) {
+                // If not password alias is configured, then try the default alias
+                if (passwordAlias == null) {
+                    passwordAlias = DEFAULT_PWD_ALIAS;
+                }
+                try {
+                    char[] pwd = aliasService.getPasswordFromAliasForGateway(passwordAlias);
+                    if (pwd != null) {
+                        password = new String(pwd);
+                    }
+
+                } catch (AliasServiceException e) {
+                    log.aliasServicePasswordError(passwordAlias, e.getLocalizedMessage());
+                }
+            }
+
+            // If the password could not be determined
+            if (password == null) {
+                log.aliasServicePasswordNotFound();
+                throw new ConfigurationException("No password is configured for Ambari service discovery.");
+            }
+
+            // Add an auth header if credentials are available
+            String encodedCreds =
+                    org.apache.commons.codec.binary.Base64.encodeBase64String((username + ":" + password).getBytes());
+            request.addHeader(new BasicHeader("Authorization", "Basic " + encodedCreds));
+
+            response = httpClient.execute(request);
+
+            if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
+                HttpEntity entity = response.getEntity();
+                if (entity != null) {
+                    result = (JSONObject) JSONValue.parse((EntityUtils.toString(entity)));
+                    log.debugJSON(result.toJSONString());
+                } else {
+                    log.noJSON(url);
+                }
+            } else {
+                log.unexpectedRestResponseStatusCode(url, response.getStatusLine().getStatusCode());
+            }
+
+        } catch (IOException e) {
+            log.restInvocationError(url, e);
+        } finally {
+            if(response != null) {
+                try {
+                    response.close();
+                } catch (IOException e) {
+                    // Ignore
+                }
+            }
+        }
+        return result;
+    }
+
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryMessages.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryMessages.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryMessages.java
new file mode 100644
index 0000000..caa16ed
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryMessages.java
@@ -0,0 +1,81 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import org.apache.hadoop.gateway.i18n.messages.Message;
+import org.apache.hadoop.gateway.i18n.messages.MessageLevel;
+import org.apache.hadoop.gateway.i18n.messages.Messages;
+import org.apache.hadoop.gateway.i18n.messages.StackTrace;
+
+@Messages(logger="org.apache.gateway.topology.discovery.ambari")
+public interface AmbariServiceDiscoveryMessages {
+
+    @Message(level = MessageLevel.ERROR,
+            text = "Encountered an error during cluster {0} discovery: {1}")
+    void clusterDiscoveryError(final String clusterName,
+                               @StackTrace(level = MessageLevel.ERROR) Exception e);
+
+
+    @Message(level = MessageLevel.DEBUG,
+            text = "REST invocation {0} failed: {1}")
+    void restInvocationError(final String url,
+                             @StackTrace(level = MessageLevel.ERROR) Exception e);
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "Encountered an error attempting to determine the user for alias {0} : {1}")
+    void aliasServiceUserError(final String alias, final String error);
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "Encountered an error attempting to determine the password for alias {0} : {1}")
+    void aliasServicePasswordError(final String alias, final String error);
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "No user configured for Ambari service discovery.")
+    void aliasServiceUserNotFound();
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "No password configured for Ambari service discovery.")
+    void aliasServicePasswordNotFound();
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "Unexpected REST invocation response code for {0} : {1}")
+    void unexpectedRestResponseStatusCode(final String url, int responseStatusCode);
+
+
+    @Message(level = MessageLevel.ERROR,
+            text = "REST invocation {0} yielded a response without any JSON.")
+    void noJSON(final String url);
+
+
+    @Message(level = MessageLevel.DEBUG,
+            text = "REST invocation result: {0}")
+    void debugJSON(final String json);
+
+
+    @Message(level = MessageLevel.INFO,
+            text = "Discovered: Service: {0}, Host: {1}")
+    void discoveredServiceHost(final String serviceName, final String hostName);
+
+
+
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryType.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryType.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryType.java
new file mode 100644
index 0000000..723a786
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceDiscoveryType.java
@@ -0,0 +1,35 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscovery;
+import org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryType;
+
+public class AmbariServiceDiscoveryType implements ServiceDiscoveryType {
+
+    private static final String IMPL = AmbariServiceDiscovery.class.getCanonicalName();
+
+    @Override
+    public String getType() {
+        return AmbariServiceDiscovery.TYPE;
+    }
+
+    @Override
+    public ServiceDiscovery newInstance() {
+        return new AmbariServiceDiscovery();
+    }
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceURLCreator.java
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceURLCreator.java b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceURLCreator.java
new file mode 100644
index 0000000..0674642
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/java/org/apache/hadoop/gateway/topology/discovery/ambari/AmbariServiceURLCreator.java
@@ -0,0 +1,184 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.gateway.topology.discovery.ambari;
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+class AmbariServiceURLCreator {
+
+    private static final String NAMENODE_SERVICE        = "NAMENODE";
+    private static final String JOBTRACKER_SERVICE      = "JOBTRACKER";
+    private static final String WEBHDFS_SERVICE         = "WEBHDFS";
+    private static final String WEBHCAT_SERVICE         = "WEBHCAT";
+    private static final String OOZIE_SERVICE           = "OOZIE";
+    private static final String WEBHBASE_SERVICE        = "WEBHBASE";
+    private static final String HIVE_SERVICE            = "HIVE";
+    private static final String RESOURCEMANAGER_SERVICE = "RESOURCEMANAGER";
+
+
+    /**
+     * Derive the endpoint URL(s) for the specified service, based on the info from the specified Cluster.
+     *
+     * @param cluster The cluster discovery results
+     * @param serviceName The name of a Hadoop service
+     *
+     * @return One or more endpoint URLs for the specified service.
+     */
+    public List<String> create(AmbariCluster cluster, String serviceName) {
+        List<String> result = null;
+
+        if (NAMENODE_SERVICE.equals(serviceName)) {
+            result = createNameNodeURL(cluster);
+        } else if (JOBTRACKER_SERVICE.equals(serviceName)) {
+            result = createJobTrackerURL(cluster);
+        } else if (WEBHDFS_SERVICE.equals(serviceName)) {
+            result = createWebHDFSURL(cluster);
+        } else if (WEBHCAT_SERVICE.equals(serviceName)) {
+            result = createWebHCatURL(cluster);
+        } else if (OOZIE_SERVICE.equals(serviceName)) {
+            result = createOozieURL(cluster);
+        } else if (WEBHBASE_SERVICE.equals(serviceName)) {
+            result = createWebHBaseURL(cluster);
+        } else if (HIVE_SERVICE.equals(serviceName)) {
+            result = createHiveURL(cluster);
+        } else if (RESOURCEMANAGER_SERVICE.equals(serviceName)) {
+            result = createResourceManagerURL(cluster);
+        }
+
+        return result;
+    }
+
+
+    private List<String> createNameNodeURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent comp = cluster.getComponent("NAMENODE");
+        if (comp != null) {
+            result.add("hdfs://" + comp.getConfigProperty("dfs.namenode.rpc-address"));
+        }
+
+        return result;
+    }
+
+
+    private List<String> createJobTrackerURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent comp = cluster.getComponent("RESOURCEMANAGER");
+        if (comp != null) {
+            result.add("rpc://" + comp.getConfigProperty("yarn.resourcemanager.address"));
+        }
+
+        return result;
+    }
+
+
+    private List<String> createWebHDFSURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariCluster.ServiceConfiguration sc = cluster.getServiceConfiguration("HDFS", "hdfs-site");
+        if (sc != null) {
+            String address = sc.getProperties().get("dfs.namenode.http-address");
+            result.add("http://" + address + "/webhdfs");
+        }
+
+        return result;
+    }
+
+
+    private List<String> createWebHCatURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent webhcat = cluster.getComponent("WEBHCAT_SERVER");
+        if (webhcat != null) {
+            String port = webhcat.getConfigProperty("templeton.port");
+            String host = webhcat.getHostNames().get(0);
+
+            result.add("http://" + host + ":" + port + "/templeton");
+        }
+        return result;
+    }
+
+
+    private List<String> createOozieURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent comp = cluster.getComponent("OOZIE_SERVER");
+        if (comp != null) {
+            result.add(comp.getConfigProperty("oozie.base.url"));
+        }
+
+        return result;
+    }
+
+
+    private List<String> createWebHBaseURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent comp = cluster.getComponent("HBASE_MASTER");
+        if (comp != null) {
+            for (String host : comp.getHostNames()) {
+                result.add("http://" + host + ":60080");
+            }
+        }
+
+        return result;
+    }
+
+
+    private List<String> createHiveURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent hive = cluster.getComponent("HIVE_SERVER");
+        if (hive != null) {
+            String path = hive.getConfigProperty("hive.server2.thrift.http.path");
+            String port = hive.getConfigProperty("hive.server2.thrift.http.port");
+            String transport = hive.getConfigProperty("hive.server2.transport.mode");
+            String useSSL = hive.getConfigProperty("hive.server2.use.SSL");
+            String host = hive.getHostNames().get(0);
+
+            String scheme = null; // What is the scheme for the binary transport mode?
+            if ("http".equals(transport)) {
+                scheme = Boolean.valueOf(useSSL) ? "https" : "http";
+            }
+
+            result.add(scheme + "://" + host + ":" + port + "/" + path);
+        }
+        return result;
+    }
+
+
+    private List<String> createResourceManagerURL(AmbariCluster cluster) {
+        List<String> result = new ArrayList<>();
+
+        AmbariComponent resMan = cluster.getComponent("RESOURCEMANAGER");
+        if (resMan != null) {
+            String webappAddress = resMan.getConfigProperty("yarn.resourcemanager.webapp.address");
+            String httpPolicy = resMan.getConfigProperty("yarn.http.policy");
+            String scheme = ("HTTPS_ONLY".equalsIgnoreCase(httpPolicy)) ? "https" : "http";
+
+            result.add(scheme + "://" + webappAddress + "/ws");
+        }
+
+        return result;
+    }
+
+
+}

http://git-wip-us.apache.org/repos/asf/knox/blob/c2ca4432/gateway-discovery-ambari/src/main/resources/META-INF/services/org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryType
----------------------------------------------------------------------
diff --git a/gateway-discovery-ambari/src/main/resources/META-INF/services/org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryType b/gateway-discovery-ambari/src/main/resources/META-INF/services/org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryType
new file mode 100644
index 0000000..1da4fc9
--- /dev/null
+++ b/gateway-discovery-ambari/src/main/resources/META-INF/services/org.apache.hadoop.gateway.topology.discovery.ServiceDiscoveryType
@@ -0,0 +1,19 @@
+##########################################################################
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+##########################################################################
+
+org.apache.hadoop.gateway.topology.discovery.ambari.AmbariServiceDiscoveryType
\ No newline at end of file