Remove Zen1

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

@@ -63,19 +63,6 @@ class ClusterConfiguration {
     @Input
     boolean debug = false
 
-    /**
-     * Configuration of the setting {@code discovery.zen.minimum_master_nodes} on the nodes.
-     * In case of more than one node, this defaults to the number of nodes
-     */
-    @Input
-    Closure<Integer> minimumMasterNodes = {
-        if (bwcVersion != null && bwcVersion.before("6.5.0")) {
-            return numNodes > 1 ? numNodes : -1
-        } else {
-            return numNodes > 1 ? numNodes.intdiv(2) + 1 : -1
-        }
-    }
-
     /**
      * Whether the initial_master_nodes setting should be automatically derived from the nodes
      * in the cluster. Only takes effect if all nodes in the cluster understand this setting

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

@@ -127,42 +127,25 @@ class ClusterFormationTasks {
             nodes.add(node)
             Closure<Map> writeConfigSetup
             Object dependsOn
-            if (node.nodeVersion.onOrAfter("6.5.0")) {
-                writeConfigSetup = { Map esConfig ->
-                    if (config.getAutoSetHostsProvider()) {
-                        // Don't force discovery provider if one is set by the test cluster specs already
-                        final String seedProvidersSettingName =
-                                node.nodeVersion.onOrAfter("7.0.0") ? "discovery.seed_providers" : "discovery.zen.hosts_provider";
-                        if (esConfig.containsKey(seedProvidersSettingName) == false) {
-                            esConfig[seedProvidersSettingName] = 'file'
-                        }
-                        esConfig[node.nodeVersion.onOrAfter("7.0.0") ? "discovery.seed_hosts" : "discovery.zen.ping.unicast.hosts"] = []
-                    }
-                    boolean supportsInitialMasterNodes = hasBwcNodes == false || config.bwcVersion.onOrAfter("7.0.0")
-                    if (esConfig['discovery.type'] == null && config.getAutoSetInitialMasterNodes() && supportsInitialMasterNodes) {
-                        esConfig['cluster.initial_master_nodes'] = nodes.stream().map({ n ->
-                            if (n.config.settings['node.name'] == null) {
-                                return "node-" + n.nodeNum
-                            } else {
-                                return n.config.settings['node.name']
-                            }
-                        }).collect(Collectors.toList())
+            writeConfigSetup = { Map esConfig ->
+                if (config.getAutoSetHostsProvider()) {
+                    if (esConfig.containsKey("discovery.seed_providers") == false) {
+                        esConfig["discovery.seed_providers"] = 'file'
                     }
-                    esConfig
+                    esConfig["discovery.seed_hosts"] = []
                 }
-                dependsOn = startDependencies
-            } else {
-                dependsOn = startTasks.empty ? startDependencies : startTasks.get(0)
-                writeConfigSetup = { Map esConfig ->
-                    String unicastTransportUri = node.config.unicastTransportUri(nodes.get(0), node, project.createAntBuilder())
-                    if (unicastTransportUri == null) {
-                        esConfig['discovery.zen.ping.unicast.hosts'] = []
-                    } else {
-                        esConfig['discovery.zen.ping.unicast.hosts'] = "\"${unicastTransportUri}\""
-                    }
-                    esConfig
+                if (esConfig['discovery.type'] == null && config.getAutoSetInitialMasterNodes()) {
+                    esConfig['cluster.initial_master_nodes'] = nodes.stream().map({ n ->
+                        if (n.config.settings['node.name'] == null) {
+                            return "node-" + n.nodeNum
+                        } else {
+                            return n.config.settings['node.name']
+                        }
+                    }).collect(Collectors.toList())
                 }
+                esConfig
             }
+            dependsOn = startDependencies
             startTasks.add(configureNode(project, prefix, runner, dependsOn, node, config, distro, writeConfigSetup))
         }
 
@@ -380,17 +363,6 @@ class ClusterFormationTasks {
                 // 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
                 'discovery.initial_state_timeout' : '0s'
         ]
-        int minimumMasterNodes = node.config.minimumMasterNodes.call()
-        if (node.nodeVersion.before("7.0.0") && minimumMasterNodes > 0) {
-            esConfig['discovery.zen.minimum_master_nodes'] = minimumMasterNodes
-        }
-        if (node.nodeVersion.before("7.0.0") && 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.
-            // This is necessary since we use 30s as the default timeout in REST requests waiting for cluster formation
-            // so we need to bail quicker than the default 30s for the cluster to form in time.
-            esConfig['discovery.zen.master_election.wait_for_joins_timeout'] = '5s'
-        }
         esConfig['node.max_local_storage_nodes'] = node.config.numNodes
         esConfig['http.port'] = node.config.httpPort
         esConfig['transport.tcp.port'] =  node.config.transportPort

docs/reference/migration/migrate_8_0.asciidoc

@@ -12,6 +12,7 @@ See also <<release-highlights>> and <<es-release-notes>>.
 coming[8.0.0]
 
 * <<breaking_80_analysis_changes>>
+* <<breaking_80_discovery_changes>>
 * <<breaking_80_mappings_changes>>
 
 [float]
@@ -31,4 +32,5 @@ Elasticsearch 7.x in order to be readable by Elasticsearch 8.x.
 =========================================
 
 include::migrate_8_0/analysis.asciidoc[]
+include::migrate_8_0/discovery.asciidoc[]
 include::migrate_8_0/mappings.asciidoc[]

docs/reference/migration/migrate_8_0/discovery.asciidoc

@@ -0,0 +1,32 @@
+[float]
+[[breaking_80_discovery_changes]]
+=== Discovery changes
+
+[float]
+==== Removal of old discovery settings
+
+All settings under the `discovery.zen` namespace, which existed only for BWC reasons in 7.x,
+will no longer be supported. In particular, this includes:
+
+- `discovery.zen.no_master_block`
+- `discovery.zen.hosts_provider`
+- `discovery.zen.publish_timeout`
+- `discovery.zen.commit_timeout`
+- `discovery.zen.publish_diff.enable`
+- `discovery.zen.ping.unicast.concurrent_connects`
+- `discovery.zen.ping.unicast.hosts.resolve_timeout`
+- `discovery.zen.ping.unicast.hosts`
+- `discovery.zen.unsafe_rolling_upgrades_enabled`
+- `discovery.zen.commit_timeout`
+- `discovery.zen.fd.connect_on_network_disconnect`
+- `discovery.zen.fd.ping_interval`
+- `discovery.zen.fd.ping_timeout`
+- `discovery.zen.fd.ping_retries`
+- `discovery.zen.fd.register_connection_listener`
+- `discovery.zen.join_retry_attempts`
+- `discovery.zen.join_retry_delay`
+- `discovery.zen.max_pings_from_another_master`
+- `discovery.zen.send_leave_request`
+- `discovery.zen.master_election.wait_for_joins_timeout`
+- `discovery.zen.master_election.ignore_non_master_pings`
+- `discovery.zen.publish.max_pending_cluster_states`

docs/reference/modules/discovery/discovery-settings.asciidoc

@@ -8,22 +8,14 @@ Discovery and cluster formation are affected by the following settings:
     Provides a list of master-eligible nodes in the cluster. Each value has the
     format `host:port` or `host`, where `port` defaults to the setting
     `transport.profiles.default.port`. Note that IPv6 hosts must be bracketed.
-    The default value is `["127.0.0.1", "[::1]"]`. See <<unicast.hosts>>. This
-    setting was previously known as `discovery.zen.ping.unicast.hosts`. Its old
-    name is deprecated but continues to work in order to preserve backwards
-    compatibility. Support for the old name will be removed in a future
-    version.
+    The default value is `["127.0.0.1", "[::1]"]`. See <<unicast.hosts>>.
 
 `discovery.seed_providers`::
 
     Specifies which types of <<built-in-hosts-providers,seed hosts provider>>
     to use to obtain the addresses of the seed nodes used to start the
     discovery process. By default, it is the
-    <<settings-based-hosts-provider,settings-based seed hosts provider>>.  This
-    setting was previously known as `discovery.zen.hosts_provider`. Its old
-    name is deprecated but continues to work in order to preserve backwards
-    compatibility. Support for the old name will be removed in a future
-    version.
+    <<settings-based-hosts-provider,settings-based seed hosts provider>>.
 
 `discovery.cluster_formation_warning_timeout`::
 
@@ -55,20 +47,12 @@ Discovery and cluster formation are affected by the following settings:
 `discovery.seed_resolver.max_concurrent_resolvers`::
 
     Specifies how many concurrent DNS lookups to perform when resolving the
-    addresses of seed nodes. Defaults to `10`. This setting was previously
-    known as `discovery.zen.ping.unicast.concurrent_connects`. Its old name is
-    deprecated but continues to work in order to preserve backwards
-    compatibility. Support for the old name will be removed in a future
-    version.
+    addresses of seed nodes. Defaults to `10`.
 
 `discovery.seed_resolver.timeout`::
 
     Specifies how long to wait for each DNS lookup performed when resolving the
-    addresses of seed nodes. Defaults to `5s`. This setting was previously
-    known as `discovery.zen.ping.unicast.hosts.resolve_timeout`. Its old name
-    is deprecated but continues to work in order to preserve backwards
-    compatibility. Support for the old name will be removed in a future
-    version.
+    addresses of seed nodes. Defaults to `5s`.
 
 `cluster.auto_shrink_voting_configuration`::
 
@@ -192,7 +176,4 @@ APIs are not be blocked and can run on any available node.
 * For the cluster to be fully operational, it must have an active master.
 ===============================
 
-WARNING: This setting replaces the `discovery.zen.no_master_block` setting in
-earlier versions. The `discovery.zen.no_master_block` setting is ignored.
-
 --

qa/logging-config/build.gradle

@@ -23,7 +23,6 @@ apply plugin: 'elasticsearch.rest-test'
 apply plugin: 'elasticsearch.standalone-test'
 
 integTestCluster {
-    autoSetInitialMasterNodes = false
     autoSetHostsProvider = false
     /**
      * Provide a custom log4j configuration where layout is an old style pattern and confirm that Elasticsearch 

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() }
-      autoSetInitialMasterNodes = false
       /* Override the data directory so the new node always gets the node we
       * just stopped's data directory. */
       dataDir = { nodeNumber -> oldClusterTest.nodes[stopNode].dataDir }

server/src/main/java/org/elasticsearch/action/admin/cluster/state/TransportClusterStateAction.java

@@ -27,6 +27,7 @@
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.ClusterStateObserver;
 import org.elasticsearch.cluster.block.ClusterBlockException;
+import org.elasticsearch.cluster.coordination.PublicationTransportHandler;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.MetaData;
@@ -42,8 +43,6 @@
 import java.io.IOException;
 import java.util.function.Predicate;
 
-import static org.elasticsearch.discovery.zen.PublishClusterStateAction.serializeFullClusterState;
-
 public class TransportClusterStateAction extends TransportMasterNodeReadAction<ClusterStateRequest, ClusterStateResponse> {
 
 
@@ -185,7 +184,7 @@ private void buildResponse(final ClusterStateRequest request,
             }
         }
         listener.onResponse(new ClusterStateResponse(currentState.getClusterName(), builder.build(),
-            serializeFullClusterState(currentState, Version.CURRENT).length(), false));
+            PublicationTransportHandler.serializeFullClusterState(currentState, Version.CURRENT).length(), false));
     }
 
 

server/src/main/java/org/elasticsearch/cluster/ClusterState.java

@@ -60,7 +60,6 @@
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.discovery.Discovery;
-import org.elasticsearch.discovery.zen.PublishClusterStateAction;
 
 import java.io.IOException;
 import java.util.EnumSet;
@@ -80,9 +79,8 @@
  * The cluster state can be updated only on the master node. All updates are performed by on a
  * single thread and controlled by the {@link ClusterService}. After every update the
  * {@link Discovery#publish} method publishes a new version of the cluster state to all other nodes in the
- * cluster.  The actual publishing mechanism is delegated to the {@link Discovery#publish} method and depends on
- * the type of discovery. In the Zen Discovery it is handled in the {@link PublishClusterStateAction#publish} method. The
- * publishing mechanism can be overridden by other discovery.
+ * cluster. The actual publishing mechanism is delegated to the {@link Discovery#publish} method and depends on
+ * the type of discovery.
  * <p>
  * The cluster state implements the {@link Diffable} interface in order to support publishing of cluster state
  * differences instead of the entire state on each change. The publishing mechanism should only send differences

server/src/main/java/org/elasticsearch/cluster/NodeConnectionsService.java

@@ -21,6 +21,8 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.elasticsearch.cluster.coordination.FollowersChecker;
+import org.elasticsearch.cluster.coordination.LeaderChecker;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.common.component.AbstractLifecycleComponent;
@@ -32,8 +34,6 @@
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.common.util.concurrent.KeyedLock;
-import org.elasticsearch.discovery.zen.MasterFaultDetection;
-import org.elasticsearch.discovery.zen.NodesFaultDetection;
 import org.elasticsearch.threadpool.Scheduler;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
@@ -51,8 +51,7 @@
  * This component is responsible for connecting to nodes once they are added to the cluster state, and disconnect when they are
  * removed. Also, it periodically checks that all connections are still open and if needed restores them.
  * Note that this component is *not* responsible for removing nodes from the cluster if they disconnect / do not respond
- * to pings. This is done by {@link NodesFaultDetection}. Master fault detection
- * is done by {@link MasterFaultDetection}.
+ * to pings. This is done by {@link FollowersChecker}. Master fault detection is done by {@link LeaderChecker}.
  */
 public class NodeConnectionsService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(NodeConnectionsService.class);

server/src/main/java/org/elasticsearch/cluster/coordination/ClusterBootstrapService.java

@@ -49,9 +49,7 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableSet;
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_SEED_PROVIDERS_SETTING;
-import static org.elasticsearch.discovery.DiscoveryModule.LEGACY_DISCOVERY_HOSTS_PROVIDER_SETTING;
 import static org.elasticsearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
-import static org.elasticsearch.discovery.SettingsBasedSeedHostsProvider.LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 
 public class ClusterBootstrapService {
 
@@ -93,8 +91,7 @@ public ClusterBootstrapService(Settings settings, TransportService transportServ
     }
 
     public static boolean discoveryIsConfigured(Settings settings) {
-        return Stream.of(DISCOVERY_SEED_PROVIDERS_SETTING, LEGACY_DISCOVERY_HOSTS_PROVIDER_SETTING,
-            DISCOVERY_SEED_HOSTS_SETTING, LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING,
+        return Stream.of(DISCOVERY_SEED_PROVIDERS_SETTING, DISCOVERY_SEED_HOSTS_SETTING,
             INITIAL_MASTER_NODES_SETTING).anyMatch(s -> s.exists(settings));
     }
 

server/src/main/java/org/elasticsearch/cluster/coordination/Coordinator.java

@@ -63,7 +63,6 @@
 import org.elasticsearch.discovery.HandshakingTransportAddressConnector;
 import org.elasticsearch.discovery.PeerFinder;
 import org.elasticsearch.discovery.SeedHostsResolver;
-import org.elasticsearch.discovery.zen.PendingClusterStateStats;
 import org.elasticsearch.discovery.SeedHostsProvider;
 import org.elasticsearch.threadpool.ThreadPool.Names;
 import org.elasticsearch.transport.TransportResponse.Empty;
@@ -1062,6 +1061,10 @@ private void cancelActivePublication(String reason) {
         }
     }
 
+    public Collection<BiConsumer<DiscoveryNode, ClusterState>> getOnJoinValidators() {
+        return onJoinValidators;
+    }
+
     public enum Mode {
         CANDIDATE, LEADER, FOLLOWER
     }

server/src/main/java/org/elasticsearch/cluster/coordination/FollowersChecker.java

@@ -22,8 +22,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.elasticsearch.cluster.ClusterName;
-import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.coordination.Coordinator.Mode;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
@@ -33,7 +31,6 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
-import org.elasticsearch.discovery.zen.NodesFaultDetection;
 import org.elasticsearch.threadpool.ThreadPool.Names;
 import org.elasticsearch.transport.ConnectTransportException;
 import org.elasticsearch.transport.TransportChannel;
@@ -114,10 +111,6 @@ public FollowersChecker(Settings settings, TransportService transportService,
         updateFastResponseState(0, Mode.CANDIDATE);
         transportService.registerRequestHandler(FOLLOWER_CHECK_ACTION_NAME, Names.SAME, false, false, FollowerCheckRequest::new,
             (request, transportChannel, task) -> handleFollowerCheck(request, transportChannel));
-        transportService.registerRequestHandler(
-            NodesFaultDetection.PING_ACTION_NAME, NodesFaultDetection.PingRequest::new, Names.SAME, false, false,
-            (request, channel, task) -> // TODO: check that we're a follower of the requesting node?
-                channel.sendResponse(new NodesFaultDetection.PingResponse()));
         transportService.addConnectionListener(new TransportConnectionListener() {
             @Override
             public void onNodeDisconnected(DiscoveryNode node) {
@@ -304,17 +297,7 @@ private void handleWakeUp() {
             final FollowerCheckRequest request = new FollowerCheckRequest(fastResponseState.term, transportService.getLocalNode());
             logger.trace("handleWakeUp: checking {} with {}", discoveryNode, request);
 
-            final String actionName;
-            final TransportRequest transportRequest;
-            if (Coordinator.isZen1Node(discoveryNode)) {
-                actionName = NodesFaultDetection.PING_ACTION_NAME;
-                transportRequest = new NodesFaultDetection.PingRequest(discoveryNode, ClusterName.CLUSTER_NAME_SETTING.get(settings),
-                    transportService.getLocalNode(), ClusterState.UNKNOWN_VERSION);
-            } else {
-                actionName = FOLLOWER_CHECK_ACTION_NAME;
-                transportRequest = request;
-            }
-            transportService.sendRequest(discoveryNode, actionName, transportRequest,
+            transportService.sendRequest(discoveryNode, FOLLOWER_CHECK_ACTION_NAME, request,
                 TransportRequestOptions.builder().withTimeout(followerCheckTimeout).withType(Type.PING).build(),
                 new TransportResponseHandler<Empty>() {
                     @Override