Deprecate minimum_master_nodes

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/ClusterFormationTasks.groovy

@@ -356,14 +356,10 @@ class ClusterFormationTasks {
                 'node.attr.testattr'           : 'test'
         ]
         int minimumMasterNodes = node.config.minimumMasterNodes.call()
-        if (minimumMasterNodes > 0) {
+        if (node.nodeVersion.before("7.0.0") && minimumMasterNodes > 0) {
             esConfig['discovery.zen.minimum_master_nodes'] = minimumMasterNodes
         }
-        if (minimumMasterNodes > 1) {
-            // don't wait for state.. just start up quickly
-            // this will also allow new and old nodes in the BWC case to become the master
-            esConfig['discovery.initial_state_timeout'] = '0s'
-        }
+        esConfig['discovery.initial_state_timeout'] = '0s'
         if (esConfig.containsKey('discovery.zen.master_election.wait_for_joins_timeout') == false) {
             // If a node decides to become master based on partial information from the pinging, don't let it hang for 30 seconds to correct
             // its mistake. Instead, only wait 5s to do another round of pinging.

docs/reference/migration/migrate_7_0/discovery.asciidoc

@@ -13,8 +13,8 @@ settings summary>> for an example, and the
 <<modules-discovery-bootstrap-cluster,cluster bootstrapping reference
 documentation>> describes this setting in more detail.
 
-The `discovery.zen.minimum_master_nodes` setting is required during a rolling
-upgrade from 6.x, but can be removed in all other circumstances.
+The `discovery.zen.minimum_master_nodes` setting is permitted, but ignored, on
+7.x nodes.
 
 [float]
 ==== Removing master-eligible nodes sometimes requires voting exclusions

modules/transport-netty4/src/test/java/org/elasticsearch/rest/discovery/Zen2RestApiIT.java

@@ -33,9 +33,7 @@
 import org.elasticsearch.cluster.routing.UnassignedInfo;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.settings.Settings.Builder;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.http.HttpServerTransport;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.InternalTestCluster;
@@ -58,11 +56,7 @@ public class Zen2RestApiIT extends ESNetty4IntegTestCase {
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
-        final Builder builder = Settings.builder().put(super.nodeSettings(nodeOrdinal))
-            .put(TestZenDiscovery.USE_ZEN2.getKey(), true)
-            .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE);
-
-        return builder.build();
+        return Settings.builder().put(super.nodeSettings(nodeOrdinal)).put(TestZenDiscovery.USE_ZEN2.getKey(), true).build();
     }
 
     @Override

plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java

@@ -21,6 +21,7 @@
 
 
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.discovery.DiscoveryModule;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
@@ -41,13 +42,14 @@ public void testMinimumMasterNodesStart() {
                 .build();
         internalCluster().startNode(nodeSettings);
 
-        // We try to update minimum_master_nodes now
-        ClusterUpdateSettingsResponse response = client().admin().cluster().prepareUpdateSettings()
-                .setPersistentSettings(Settings.builder().put("discovery.zen.minimum_master_nodes", 1))
-                .setTransientSettings(Settings.builder().put("discovery.zen.minimum_master_nodes", 1))
+        // We try to update a setting now
+        final String expectedValue = UUIDs.randomBase64UUID(random());
+        final String settingName = "cluster.routing.allocation.exclude.any_attribute";
+        final ClusterUpdateSettingsResponse response = client().admin().cluster().prepareUpdateSettings()
+                .setPersistentSettings(Settings.builder().put(settingName, expectedValue))
                 .get();
 
-        Integer min = response.getPersistentSettings().getAsInt("discovery.zen.minimum_master_nodes", null);
-        assertThat(min, is(1));
+        final String value = response.getPersistentSettings().get(settingName);
+        assertThat(value, is(expectedValue));
     }
 }

qa/rolling-upgrade/build.gradle

@@ -77,7 +77,6 @@ for (Version version : bwcVersions.wireCompatible) {
       dependsOn lastRunner, "${baseName}#oldClusterTestCluster#node${stopNode}.stop"
       clusterName = 'rolling-upgrade'
       otherUnicastHostAddresses = { getOtherUnicastHostAddresses() }
-      minimumMasterNodes = { 2 }
       autoSetInitialMasterNodes = false
       /* Override the data directory so the new node always gets the node we
       * just stopped's data directory. */

rest-api-spec/src/main/resources/rest-api-spec/test/cluster.put_settings/10_basic.yml

@@ -4,22 +4,22 @@
       cluster.put_settings:
         body:
           transient:
-            discovery.zen.minimum_master_nodes: 1
+            cluster.routing.allocation.enable: "none"
         flat_settings: true
 
-  - match: {transient: {discovery.zen.minimum_master_nodes: "1"}}
+  - match: {transient: {cluster.routing.allocation.enable: "none"}}
 
   - do:
       cluster.get_settings:
         flat_settings: true
 
-  - match: {transient: {discovery.zen.minimum_master_nodes: "1"}}
+  - match: {transient: {cluster.routing.allocation.enable: "none"}}
 
   - do:
       cluster.put_settings:
         body:
           transient:
-            discovery.zen.minimum_master_nodes: null
+            cluster.routing.allocation.enable: null
         flat_settings: true
 
   - match: {transient: {}}
@@ -35,22 +35,22 @@
       cluster.put_settings:
         body:
           persistent:
-            cluster.routing.allocation.disk.threshold_enabled: false
+            cluster.routing.allocation.enable: "none"
         flat_settings: true
 
-  - match: {persistent: {cluster.routing.allocation.disk.threshold_enabled: "false"}}
+  - match: {persistent: {cluster.routing.allocation.enable: "none"}}
 
   - do:
       cluster.get_settings:
         flat_settings: true
 
-  - match: {persistent: {cluster.routing.allocation.disk.threshold_enabled: "false"}}
+  - match: {persistent: {cluster.routing.allocation.enable: "none"}}
 
   - do:
       cluster.put_settings:
         body:
           persistent:
-            cluster.routing.allocation.disk.threshold_enabled: null
+            cluster.routing.allocation.enable: null
         flat_settings: true
 
   - match: {persistent: {}}

server/src/main/java/org/elasticsearch/discovery/zen/ElectMasterService.java

@@ -42,7 +42,7 @@ public class ElectMasterService {
     private static final Logger logger = LogManager.getLogger(ElectMasterService.class);
 
     public static final Setting<Integer> DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING =
-        Setting.intSetting("discovery.zen.minimum_master_nodes", -1, Property.Dynamic, Property.NodeScope);
+        Setting.intSetting("discovery.zen.minimum_master_nodes", -1, Property.Dynamic, Property.NodeScope, Property.Deprecated);
 
     private volatile int minimumMasterNodes;
 

server/src/test/java/org/elasticsearch/action/admin/indices/exists/IndicesExistsIT.java

@@ -23,7 +23,6 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.discovery.MasterNotDiscoveredException;
-import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.gateway.GatewayService;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
@@ -51,8 +50,7 @@ protected List<Settings> addExtraClusterBootstrapSettings(List<Settings> allNode
 
     public void testIndexExistsWithBlocksInPlace() throws IOException {
         Settings settings = Settings.builder()
-            .put(GatewayService.RECOVER_AFTER_NODES_SETTING.getKey(), 99)
-            .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE).build();
+            .put(GatewayService.RECOVER_AFTER_NODES_SETTING.getKey(), 99).build();
         String node = internalCluster().startNode(settings);
 
         assertThrows(client(node).admin().indices().prepareExists("test").setMasterNodeTimeout(TimeValue.timeValueSeconds(0)),

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

@@ -26,14 +26,13 @@
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.cluster.coordination.ClusterBootstrapService;
+import org.elasticsearch.cluster.coordination.FailedToCommitClusterStateException;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.discovery.DiscoverySettings;
-import org.elasticsearch.cluster.coordination.FailedToCommitClusterStateException;
-import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.discovery.zen.ZenDiscovery;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.node.Node;
@@ -102,7 +101,6 @@ public void testTwoNodesNoMasterBlock() throws Exception {
         bootstrapNodeId = 2;
 
         Settings settings = Settings.builder()
-                .put("discovery.zen.minimum_master_nodes", 2)
                 .put(ZenDiscovery.PING_TIMEOUT_SETTING.getKey(), "200ms")
                 .put("discovery.initial_state_timeout", "500ms")
                 .build();
@@ -237,7 +235,6 @@ public void testThreeNodesNoMasterBlock() throws Exception {
         bootstrapNodeId = 3;
 
         Settings settings = Settings.builder()
-                .put("discovery.zen.minimum_master_nodes", 3)
                 .put(ZenDiscovery.PING_TIMEOUT_SETTING.getKey(), "1s")
                 .put("discovery.initial_state_timeout", "500ms")
                 .build();
@@ -316,11 +313,9 @@ public void testCannotCommitStateThreeNodes() throws Exception {
         Settings settings = Settings.builder()
                 .put(ZenDiscovery.PING_TIMEOUT_SETTING.getKey(), "200ms")
                 .put("discovery.initial_state_timeout", "500ms")
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), 2)
                 .put(DiscoverySettings.COMMIT_TIMEOUT_SETTING.getKey(), "100ms") // speed things up
                 .build();
 
-
         internalCluster().startNodes(3, settings);
         ensureGreen(); // ensure cluster state is recovered before we disrupt things
 

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

@@ -38,7 +38,6 @@
 import java.util.List;
 import java.util.concurrent.ExecutionException;
 
-import static org.elasticsearch.discovery.zen.ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
@@ -47,12 +46,6 @@
 @TestLogging("_root:DEBUG,org.elasticsearch.action.admin.cluster.state:TRACE")
 public class SpecificMasterNodesIT extends ESIntegTestCase {
 
-    @Override
-    protected Settings nodeSettings(int nodeOrdinal) {
-        return Settings.builder().put(super.nodeSettings(nodeOrdinal))
-            .put(DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), 1).build();
-    }
-
     @Override
     protected List<Settings> addExtraClusterBootstrapSettings(List<Settings> allNodesSettings) {
         // if it's the first master in the cluster bootstrap the cluster with this node name

server/src/test/java/org/elasticsearch/cluster/coordination/UnsafeBootstrapMasterIT.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.discovery.DiscoverySettings;
-import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.env.NodeMetaData;
@@ -155,7 +154,6 @@ public void testNoNodeMetaData() throws IOException {
     public void testNotBootstrappedCluster() throws Exception {
         internalCluster().startNode(
                 Settings.builder()
-                        .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
                         .put(DiscoverySettings.INITIAL_STATE_TIMEOUT_SETTING.getKey(), "0s") // to ensure quick node startup
                         .build());
         assertBusy(() -> {
@@ -172,9 +170,7 @@ public void testNotBootstrappedCluster() throws Exception {
 
     public void testNoManifestFile() throws IOException {
         bootstrapNodeId = 1;
-        internalCluster().startNode(Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        internalCluster().startNode();
         ensureStableCluster(1);
         NodeEnvironment nodeEnvironment = internalCluster().getMasterNodeInstance(NodeEnvironment.class);
         internalCluster().stopRandomDataNode();
@@ -186,9 +182,7 @@ public void testNoManifestFile() throws IOException {
 
     public void testNoMetaData() throws IOException {
         bootstrapNodeId = 1;
-        internalCluster().startNode(Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        internalCluster().startNode();
         ensureStableCluster(1);
         NodeEnvironment nodeEnvironment = internalCluster().getMasterNodeInstance(NodeEnvironment.class);
         internalCluster().stopRandomDataNode();
@@ -201,9 +195,7 @@ public void testNoMetaData() throws IOException {
 
     public void testAbortedByUser() throws IOException {
         bootstrapNodeId = 1;
-        internalCluster().startNode(Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        internalCluster().startNode();
         ensureStableCluster(1);
         internalCluster().stopRandomDataNode();
 
@@ -213,13 +205,9 @@ public void testAbortedByUser() throws IOException {
 
     public void test3MasterNodes2Failed() throws Exception {
         bootstrapNodeId = 3;
-        List<String> masterNodes = internalCluster().startMasterOnlyNodes(3, Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        List<String> masterNodes = internalCluster().startMasterOnlyNodes(3, Settings.EMPTY);
 
-        String dataNode = internalCluster().startDataOnlyNode(Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        String dataNode = internalCluster().startDataOnlyNode();
         createIndex("test");
 
         Client dataNodeClient = internalCluster().client(dataNode);
@@ -246,9 +234,7 @@ public void test3MasterNodes2Failed() throws Exception {
                 String.format(Locale.ROOT, UnsafeBootstrapMasterCommand.CLUSTER_STATE_TERM_VERSION_MSG_FORMAT,
                         metaData.coordinationMetaData().term(), metaData.version())));
 
-        internalCluster().startMasterOnlyNode(Settings.builder()
-                .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
-                .build());
+        internalCluster().startMasterOnlyNode();
 
         assertBusy(() -> {
             ClusterState state = dataNodeClient.admin().cluster().prepareState().setLocal(true)

server/src/test/java/org/elasticsearch/cluster/coordination/Zen1IT.java

@@ -34,6 +34,7 @@
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.gateway.MetaStateService;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -194,7 +195,8 @@ public Settings onNodeStopped(String nodeName) {
                 }
                 ClusterHealthResponse clusterHealthResponse = clusterHealthRequestBuilder.get();
                 assertFalse(nodeName, clusterHealthResponse.isTimedOut());
-                return Coordinator.addZen1Attribute(false, Settings.builder().put(ZEN2_SETTINGS)).build();
+                return Coordinator.addZen1Attribute(false, Settings.builder().put(ZEN2_SETTINGS)
+                    .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)).build();
             }
         });
 
@@ -289,6 +291,7 @@ public Settings onNodeStopped(String nodeName) throws Exception {
                 return Coordinator.addZen1Attribute(false, Settings.builder())
                     .put(ZEN2_SETTINGS)
                     .putList(INITIAL_MASTER_NODES_SETTING.getKey(), nodeNames)
+                    .put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), Integer.MAX_VALUE)
                     .build();
             }
         });

server/src/test/java/org/elasticsearch/discovery/MasterDisruptionIT.java

@@ -35,7 +35,6 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentType;
-import org.elasticsearch.discovery.zen.ElectMasterService;
 import org.elasticsearch.discovery.zen.ZenDiscovery;
 import org.elasticsearch.monitor.jvm.HotThreads;
 import org.elasticsearch.test.ESIntegTestCase;
@@ -125,11 +124,6 @@ public void testNodesFDAfterMasterReelection() throws Exception {
 
         ensureStableCluster(3);
 
-        logger.info("--> reducing min master nodes to 2");
-        assertAcked(client().admin().cluster().prepareUpdateSettings()
-                .setTransientSettings(Settings.builder().put(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES_SETTING.getKey(), 2))
-                .get());
-
         String master = internalCluster().getMasterName();
         String nonMaster = null;
         for (String node : internalCluster().getNodeNames()) {
@@ -154,7 +148,7 @@ public void testNodesFDAfterMasterReelection() throws Exception {
      */
     @TestLogging("_root:DEBUG,org.elasticsearch.cluster.service:TRACE,org.elasticsearch.test.disruption:TRACE")
     public void testStaleMasterNotHijackingMajority() throws Exception {
-        // 3 node cluster with unicast discovery and minimum_master_nodes set to the default of 2:
+        // 3 node cluster with unicast discovery:
         final List<String> nodes = startCluster(3);
 
         // Save the current master node as old master node, because that node will get frozen