Use file-based discovery not MockUncasedHostsProvider (#33658)

Today we use a special unicast hosts provider, the `MockUncasedHostsProvider`,
in many integration tests, to deal with the dynamic nature of the allocation of
ports to nodes. However #33241 allows us to use file-based discovery to achieve
the same goal, so the special test-only `MockUncasedHostsProvider` is no longer
required.

This change removes `MockUncasedHostProvider` and replaces it with file-based
discovery in tests based on `EsIntegTestCase`.

Backport of #33554 to 6.x.

Author: DaveCTurner

server/src/main/java/org/elasticsearch/discovery/DiscoveryModule.java

@@ -131,7 +131,7 @@ public DiscoveryModule(Settings settings, ThreadPool threadPool, TransportServic
         if (discoverySupplier == null) {
             throw new IllegalArgumentException("Unknown discovery type [" + discoveryType + "]");
         }
-        Loggers.getLogger(getClass(), settings).info("using discovery type [{}]", discoveryType);
+        Loggers.getLogger(getClass(), settings).info("using discovery type [{}] and host providers {}", discoveryType, hostsProviderNames);
         discovery = Objects.requireNonNull(discoverySupplier.get());
     }
 

server/src/test/java/org/elasticsearch/cluster/ClusterInfoServiceIT.java

@@ -53,7 +53,6 @@
 import java.util.Collection;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static java.util.Collections.emptySet;
@@ -113,6 +112,7 @@ public void blockActions(String... actions) {
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
         return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
             // manual collection or upon cluster forming.
             .put(NodeEnvironment.MAX_LOCAL_STORAGE_NODES_SETTING.getKey(), 2)
             .put(InternalClusterInfoService.INTERNAL_CLUSTER_INFO_TIMEOUT_SETTING.getKey(), "1s")
@@ -121,8 +121,7 @@ protected Settings nodeSettings(int nodeOrdinal) {
 
     @Override
     protected Collection<Class<? extends Plugin>> nodePlugins() {
-        return Arrays.asList(TestPlugin.class,
-            MockTransportService.TestPlugin.class);
+        return Arrays.asList(TestPlugin.class, MockTransportService.TestPlugin.class);
     }
 
     public void testClusterInfoServiceCollectsInformation() throws Exception {
@@ -172,7 +171,7 @@ public void testClusterInfoServiceCollectsInformation() throws Exception {
         }
     }
 
-    public void testClusterInfoServiceInformationClearOnError() throws InterruptedException, ExecutionException {
+    public void testClusterInfoServiceInformationClearOnError() {
         internalCluster().startNodes(2,
             // manually control publishing
             Settings.builder().put(InternalClusterInfoService.INTERNAL_CLUSTER_INFO_UPDATE_INTERVAL_SETTING.getKey(), "60m").build());

server/src/test/java/org/elasticsearch/discovery/zen/SettingsBasedHostProviderIT.java

@@ -0,0 +1,81 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.discovery.zen;
+
+import org.elasticsearch.action.admin.cluster.node.info.NodesInfoRequest;
+import org.elasticsearch.action.admin.cluster.node.info.NodesInfoResponse;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.test.ESIntegTestCase;
+
+import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_HOSTS_PROVIDER_SETTING;
+import static org.elasticsearch.discovery.zen.SettingsBasedHostsProvider.DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
+import static org.elasticsearch.discovery.zen.SettingsBasedHostsProvider.LIMIT_LOCAL_PORTS_COUNT;
+import static org.elasticsearch.transport.TcpTransport.PORT;
+
+@ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
+public class SettingsBasedHostProviderIT extends ESIntegTestCase {
+
+    @Override
+    protected Settings nodeSettings(int nodeOrdinal) {
+        Settings.Builder builder = Settings.builder().put(super.nodeSettings(nodeOrdinal));
+
+        // super.nodeSettings enables file-based discovery, but here we disable it again so we can test the static list:
+        if (randomBoolean()) {
+            builder.putList(DISCOVERY_HOSTS_PROVIDER_SETTING.getKey());
+        } else {
+            builder.remove(DISCOVERY_HOSTS_PROVIDER_SETTING.getKey());
+        }
+
+        // super.nodeSettings sets this to an empty list, which disables any search for other nodes, but here we want this to happen:
+        builder.remove(DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey());
+
+        return builder.build();
+    }
+
+    public void testClusterFormsWithSingleSeedHostInSettings() {
+        final String seedNodeName = internalCluster().startNode();
+        final NodesInfoResponse nodesInfoResponse
+            = client(seedNodeName).admin().cluster().nodesInfo(new NodesInfoRequest("_local")).actionGet();
+        final String seedNodeAddress = nodesInfoResponse.getNodes().get(0).getTransport().getAddress().publishAddress().toString();
+        logger.info("--> using seed node address {}", seedNodeAddress);
+
+        int extraNodes = randomIntBetween(1, 5);
+        internalCluster().startNodes(extraNodes,
+            Settings.builder().putList(DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey(), seedNodeAddress).build());
+
+        ensureStableCluster(extraNodes + 1);
+    }
+
+    public void testClusterFormsByScanningPorts() {
+        // This test will fail if all 4 ports just less than the one used by the first node are already bound by something else. It's hard
+        // to know how often this might happen in reality, so let's try it and see.
+
+        final String seedNodeName = internalCluster().startNode();
+        final NodesInfoResponse nodesInfoResponse
+            = client(seedNodeName).admin().cluster().nodesInfo(new NodesInfoRequest("_local")).actionGet();
+        final int seedNodePort = nodesInfoResponse.getNodes().get(0).getTransport().getAddress().publishAddress().getPort();
+        final int minPort = randomIntBetween(seedNodePort - LIMIT_LOCAL_PORTS_COUNT + 1, seedNodePort - 1);
+        final String portSpec = minPort + "-" + seedNodePort;
+
+        logger.info("--> using port specification [{}]", portSpec);
+        internalCluster().startNode(Settings.builder().put(PORT.getKey(), portSpec));
+        ensureStableCluster(2);
+    }
+}

server/src/test/java/org/elasticsearch/search/SearchCancellationIT.java

@@ -69,7 +69,10 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
     protected Settings nodeSettings(int nodeOrdinal) {
         boolean lowLevelCancellation = randomBoolean();
         logger.info("Using lowLevelCancellation: {}", lowLevelCancellation);
-        return Settings.builder().put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), lowLevelCancellation).build();
+        return Settings.builder()
+            .put(super.nodeSettings(nodeOrdinal))
+            .put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), lowLevelCancellation)
+            .build();
     }
 
     private void indexTestData() {

test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java

@@ -206,6 +206,8 @@
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_REPLICAS;
 import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_NUMBER_OF_SHARDS;
 import static org.elasticsearch.common.util.CollectionUtils.eagerPartition;
+import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_HOSTS_PROVIDER_SETTING;
+import static org.elasticsearch.discovery.zen.SettingsBasedHostsProvider.DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.test.XContentTestUtils.convertToMap;
 import static org.elasticsearch.test.XContentTestUtils.differenceBetweenMapsIgnoringArrayOrder;
@@ -1808,7 +1810,9 @@ protected Settings nodeSettings(int nodeOrdinal) {
             // wait short time for other active shards before actually deleting, default 30s not needed in tests
             .put(IndicesStore.INDICES_STORE_DELETE_SHARD_TIMEOUT.getKey(), new TimeValue(1, TimeUnit.SECONDS))
             // randomly enable low-level search cancellation to make sure it does not alter results
-            .put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), randomBoolean());
+            .put(SearchService.LOW_LEVEL_CANCELLATION_SETTING.getKey(), randomBoolean())
+            .putList(DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey()) // empty list disables a port scan for other nodes
+            .putList(DISCOVERY_HOSTS_PROVIDER_SETTING.getKey(), "file");
         if (rarely()) {
             // Sometimes adjust the minimum search thread pool size, causing
             // QueueResizingEsThreadPoolExecutor to be used instead of a regular
@@ -1921,7 +1925,7 @@ protected NodeConfigurationSource getNodeConfigSource() {
             networkSettings.put(NetworkModule.TRANSPORT_TYPE_KEY, getTestTransportType());
         }
 
-        NodeConfigurationSource nodeConfigurationSource = new NodeConfigurationSource() {
+        return new NodeConfigurationSource() {
             @Override
             public Settings nodeSettings(int nodeOrdinal) {
                 return Settings.builder()
@@ -1956,7 +1960,6 @@ public Collection<Class<? extends Plugin>> transportClientPlugins() {
                 return Collections.unmodifiableCollection(plugins);
             }
         };
-        return nodeConfigurationSource;
     }
 
     /**
@@ -2023,7 +2026,7 @@ protected Collection<Class<? extends Plugin>> getMockPlugins() {
     public static final class TestSeedPlugin extends Plugin {
         @Override
         public List<Setting<?>> getSettings() {
-            return Arrays.asList(INDEX_TEST_SEED_SETTING);
+            return Collections.singletonList(INDEX_TEST_SEED_SETTING);
         }
     }
 

test/framework/src/main/java/org/elasticsearch/test/ESSingleNodeTestCase.java

@@ -62,6 +62,7 @@
 import java.util.Collection;
 import java.util.Collections;
 
+import static org.elasticsearch.discovery.zen.SettingsBasedHostsProvider.DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.lessThanOrEqualTo;
@@ -190,6 +191,7 @@ private Node newNode() {
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_LOW_DISK_WATERMARK_SETTING.getKey(), "1b")
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_HIGH_DISK_WATERMARK_SETTING.getKey(), "1b")
             .put(DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_FLOOD_STAGE_WATERMARK_SETTING.getKey(), "1b")
+            .putList(DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING.getKey()) // empty list disables a port scan for other nodes
             .put(nodeSettings()) // allow test cases to provide their own settings or override these
             .build();
         Collection<Class<? extends Plugin>> plugins = getPlugins();