[TEST] Added test to verify if 'discovery.zen.rejoin_on_master_gone' is updatable at runtime.

src/main/java/org/elasticsearch/cluster/settings/ClusterDynamicSettingsModule.java

@@ -27,6 +27,7 @@ import org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllo
 import org.elasticsearch.cluster.routing.allocation.decider.*;
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.discovery.DiscoverySettings;
+import org.elasticsearch.discovery.zen.ZenDiscovery;
 import org.elasticsearch.discovery.zen.elect.ElectMasterService;
 import org.elasticsearch.indices.breaker.HierarchyCircuitBreakerService;
 import org.elasticsearch.indices.cache.filter.IndicesFilterCache;
@@ -57,6 +58,7 @@ public class ClusterDynamicSettingsModule extends AbstractModule {
         clusterDynamicSettings.addDynamicSetting(DisableAllocationDecider.CLUSTER_ROUTING_ALLOCATION_DISABLE_ALLOCATION);
         clusterDynamicSettings.addDynamicSetting(DisableAllocationDecider.CLUSTER_ROUTING_ALLOCATION_DISABLE_REPLICA_ALLOCATION);
         clusterDynamicSettings.addDynamicSetting(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES, Validator.INTEGER);
+        clusterDynamicSettings.addDynamicSetting(ZenDiscovery.REJOIN_ON_MASTER_GONE, Validator.BOOLEAN);
         clusterDynamicSettings.addDynamicSetting(FilterAllocationDecider.CLUSTER_ROUTING_INCLUDE_GROUP + "*");
         clusterDynamicSettings.addDynamicSetting(FilterAllocationDecider.CLUSTER_ROUTING_EXCLUDE_GROUP + "*");
         clusterDynamicSettings.addDynamicSetting(FilterAllocationDecider.CLUSTER_ROUTING_REQUIRE_GROUP + "*");

src/main/java/org/elasticsearch/discovery/zen/ZenDiscovery.java

@@ -77,7 +77,7 @@ import static org.elasticsearch.common.unit.TimeValue.timeValueSeconds;
  */
 public class ZenDiscovery extends AbstractLifecycleComponent<Discovery> implements Discovery, DiscoveryNodesProvider {
 
-    private final static String REJOIN_ON_MASTER_GONE = "discovery.zen.rejoin_on_master_gone";
+    public final static String REJOIN_ON_MASTER_GONE = "discovery.zen.rejoin_on_master_gone";
 
     public static final String DISCOVERY_REJOIN_ACTION_NAME = "internal:discovery/zen/rejoin";
 
@@ -973,6 +973,10 @@ public class ZenDiscovery extends AbstractLifecycleComponent<Discovery> implemen
         }
     }
 
+    boolean isRejoinOnMasterGone() {
+        return rejoinOnMasterGone;
+    }
+
     static class RejoinClusterRequest extends TransportRequest {
 
         private String fromNodeId;

src/test/java/org/elasticsearch/discovery/zen/ZenDiscoveryRejoinOnMaster.java

@@ -0,0 +1,51 @@
+/*
+ * 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.common.settings.ImmutableSettings;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.discovery.Discovery;
+import org.elasticsearch.test.ElasticsearchIntegrationTest;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.is;
+
+/**
+ */
+@ElasticsearchIntegrationTest.ClusterScope(scope = ElasticsearchIntegrationTest.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
+public class ZenDiscoveryRejoinOnMaster extends ElasticsearchIntegrationTest {
+
+    @Test
+    public void testChangeRejoinOnMaster() throws Exception {
+        Settings nodeSettings = ImmutableSettings.settingsBuilder()
+                .put("discovery.type", "zen") // <-- To override the local setting if set externally
+                .build();
+        String nodeName = internalCluster().startNode(nodeSettings);
+        ZenDiscovery zenDiscovery = (ZenDiscovery) internalCluster().getInstance(Discovery.class, nodeName);
+        assertThat(zenDiscovery.isRejoinOnMasterGone(), is(true));
+
+        client().admin().cluster().prepareUpdateSettings()
+                .setTransientSettings(ImmutableSettings.builder().put(ZenDiscovery.REJOIN_ON_MASTER_GONE, false))
+                .get();
+
+        assertThat(zenDiscovery.isRejoinOnMasterGone(), is(false));
+    }
+
+}