[Javadocs] add to o.o.cluster (#3170)

Adds javadocs to classes in the o.o.cluster package.

Signed-off-by: Nicholas Walter Knize <nknize@apache.org>

server/src/main/java/org/opensearch/cluster/AbstractDiffable.java

@@ -41,6 +41,8 @@ import java.io.IOException;
 /**
  * Abstract diffable object with simple diffs implementation that sends the entire object if object has changed or
  * nothing if object remained the same.
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractDiffable<T extends Diffable<T>> implements Diffable<T> {
 

server/src/main/java/org/opensearch/cluster/AbstractNamedDiffable.java

@@ -43,6 +43,8 @@ import java.io.IOException;
 /**
  * Abstract diffable object with simple diffs implementation that sends the entire object if object has changed or
  * nothing is object remained the same. Comparing to AbstractDiffable, this class also works with NamedWriteables
+ *
+ * @opensearch.internal
  */
 public abstract class AbstractNamedDiffable<T extends NamedDiffable<T>> implements Diffable<T>, NamedWriteable {
 

server/src/main/java/org/opensearch/cluster/AckedClusterStateTaskListener.java

@@ -35,6 +35,11 @@ import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Listener when cluster state task is acknowledged
+ *
+ * @opensearch.internal
+ */
 public interface AckedClusterStateTaskListener extends ClusterStateTaskListener {
 
     /**

server/src/main/java/org/opensearch/cluster/AckedClusterStateUpdateTask.java

@@ -41,6 +41,8 @@ import org.opensearch.common.unit.TimeValue;
 /**
  * An extension interface to {@link ClusterStateUpdateTask} that allows to be notified when
  * all the nodes have acknowledged a cluster state update request
+ *
+ * @opensearch.internal
  */
 public abstract class AckedClusterStateUpdateTask<Response> extends ClusterStateUpdateTask implements AckedClusterStateTaskListener {
 

server/src/main/java/org/opensearch/cluster/ClusterChangedEvent.java

@@ -53,6 +53,8 @@ import java.util.stream.Collectors;
 
 /**
  * An event received by the local node, signaling that the cluster state has changed.
+ *
+ * @opensearch.internal
  */
 public class ClusterChangedEvent {
 

server/src/main/java/org/opensearch/cluster/ClusterInfo.java

@@ -55,6 +55,8 @@ import java.util.Objects;
  * and a map of shard ids to shard sizes, see
  * <code>InternalClusterInfoService.shardIdentifierFromRouting(String)</code>
  * for the key used in the shardSizes map
+ *
+ * @opensearch.internal
  */
 public class ClusterInfo implements ToXContentFragment, Writeable {
     private final ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsage;

server/src/main/java/org/opensearch/cluster/ClusterInfoService.java

@@ -36,6 +36,8 @@ import java.util.function.Consumer;
 
 /**
  * Interface for a class used to gather information about a cluster periodically.
+ *
+ * @opensearch.internal
  */
 @FunctionalInterface
 public interface ClusterInfoService {

server/src/main/java/org/opensearch/cluster/ClusterModule.java

@@ -110,6 +110,8 @@ import java.util.function.Supplier;
 
 /**
  * Configures classes and services that affect the entire cluster.
+ *
+ * @opensearch.internal
  */
 public class ClusterModule extends AbstractModule {
 

server/src/main/java/org/opensearch/cluster/ClusterName.java

@@ -42,6 +42,11 @@ import java.io.IOException;
 import java.util.Objects;
 import java.util.function.Predicate;
 
+/**
+ * Cluster Name
+ *
+ * @opensearch.internal
+ */
 public class ClusterName implements Writeable {
 
     public static final Setting<ClusterName> CLUSTER_NAME_SETTING = new Setting<>("cluster.name", "opensearch", (s) -> {

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

@@ -97,6 +97,8 @@ import static org.opensearch.cluster.coordination.Coordinator.ZEN1_BWC_TERM;
  * make sure that the correct diffs are applied. If uuids don’t match, the {@link ClusterStateDiff#apply} method
  * throws the {@link IncompatibleClusterStateVersionException}, which causes the publishing mechanism to send
  * a full version of the cluster state to the node on which this exception was thrown.
+ *
+ * @opensearch.internal
  */
 public class ClusterState implements ToXContentFragment, Diffable<ClusterState> {
 

server/src/main/java/org/opensearch/cluster/ClusterStateApplier.java

@@ -37,6 +37,8 @@ import org.opensearch.cluster.service.ClusterService;
 /**
  * A component that is in charge of applying an incoming cluster state to the node internal data structures.
  * The single apply method is called before the cluster state becomes visible via {@link ClusterService#state()}.
+ *
+ * @opensearch.internal
  */
 public interface ClusterStateApplier {
 

server/src/main/java/org/opensearch/cluster/ClusterStateListener.java

@@ -35,7 +35,7 @@ package org.opensearch.cluster;
 /**
  * A listener to be notified when a cluster state changes.
  *
- *
+ * @opensearch.internal
  */
 public interface ClusterStateListener {
 

server/src/main/java/org/opensearch/cluster/ClusterStateObserver.java

@@ -50,6 +50,8 @@ import java.util.function.Supplier;
  * A utility class which simplifies interacting with the cluster state in cases where
  * one tries to take action based on the current state but may want to wait for a new state
  * and retry upon failure.
+ *
+ * @opensearch.internal
  */
 public class ClusterStateObserver {
 

server/src/main/java/org/opensearch/cluster/ClusterStateTaskConfig.java

@@ -37,6 +37,8 @@ import org.opensearch.common.unit.TimeValue;
 
 /**
  * Cluster state update task configuration for timeout and priority
+ *
+ * @opensearch.internal
  */
 public interface ClusterStateTaskConfig {
     /**

server/src/main/java/org/opensearch/cluster/ClusterStateTaskExecutor.java

@@ -37,6 +37,11 @@ import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
 
+/**
+ * Interface that updates the cluster state based on the task
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStateTaskExecutor<T> {
     /**
      * Update the cluster state based on the current state and the given tasks. Return the *same instance* if no state

server/src/main/java/org/opensearch/cluster/ClusterStateTaskListener.java

@@ -35,6 +35,11 @@ import org.opensearch.cluster.service.MasterService;
 
 import java.util.List;
 
+/**
+ * Interface to implement a cluster state change listener
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStateTaskListener {
 
     /**

server/src/main/java/org/opensearch/cluster/ClusterStateUpdateTask.java

@@ -40,6 +40,8 @@ import java.util.List;
 
 /**
  * A task that can update the cluster state.
+ *
+ * @opensearch.internal
  */
 public abstract class ClusterStateUpdateTask
     implements

server/src/main/java/org/opensearch/cluster/Diff.java

@@ -36,6 +36,8 @@ import org.opensearch.common.io.stream.Writeable;
 
 /**
  * Represents difference between states of cluster state parts
+ *
+ * @opensearch.internal
  */
 public interface Diff<T> extends Writeable {
 

server/src/main/java/org/opensearch/cluster/Diffable.java

@@ -36,6 +36,8 @@ import org.opensearch.common.io.stream.Writeable;
 
 /**
  * Cluster state part, changes in which can be serialized
+ *
+ * @opensearch.internal
  */
 public interface Diffable<T> extends Writeable {
 

server/src/main/java/org/opensearch/cluster/DiffableUtils.java

@@ -53,6 +53,11 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+/**
+ * Utility class for a diffable
+ *
+ * @opensearch.internal
+ */
 public final class DiffableUtils {
     private DiffableUtils() {}
 

server/src/main/java/org/opensearch/cluster/DiskUsage.java

@@ -45,6 +45,8 @@ import java.util.Objects;
 
 /**
  * Encapsulation class used to represent the amount of disk used on a node.
+ *
+ * @opensearch.internal
  */
 public class DiskUsage implements ToXContentFragment, Writeable {
     final String nodeId;

server/src/main/java/org/opensearch/cluster/EmptyClusterInfoService.java

@@ -36,6 +36,8 @@ import java.util.function.Consumer;
 
 /**
  * {@link ClusterInfoService} that provides empty maps for disk usage and shard sizes
+ *
+ * @opensearch.internal
  */
 public class EmptyClusterInfoService implements ClusterInfoService {
     public static final EmptyClusterInfoService INSTANCE = new EmptyClusterInfoService();

server/src/main/java/org/opensearch/cluster/IncompatibleClusterStateVersionException.java

@@ -39,6 +39,8 @@ import java.io.IOException;
 
 /**
  * Thrown by {@link Diff#apply} method
+ *
+ * @opensearch.internal
  */
 public class IncompatibleClusterStateVersionException extends OpenSearchException {
     public IncompatibleClusterStateVersionException(String msg) {

server/src/main/java/org/opensearch/cluster/InternalClusterInfoService.java

@@ -83,6 +83,8 @@ import java.util.function.Consumer;
  *
  * Every time the timer runs, gathers information about the disk usage and
  * shard sizes across the cluster.
+ *
+ * @opensearch.internal
  */
 public class InternalClusterInfoService implements ClusterInfoService, ClusterStateListener {
 

server/src/main/java/org/opensearch/cluster/LocalClusterUpdateTask.java

@@ -39,6 +39,8 @@ import java.util.List;
 
 /**
  * Used to apply state updates on nodes that are not necessarily cluster-manager
+ *
+ * @opensearch.internal
  */
 public abstract class LocalClusterUpdateTask
     implements

server/src/main/java/org/opensearch/cluster/LocalNodeMasterListener.java

@@ -34,6 +34,8 @@ package org.opensearch.cluster;
 /**
  * Enables listening to cluster-manager changes events of the local node (when the local node becomes the cluster-manager, and when the local
  * node cease being a cluster-manager).
+ *
+ * @opensearch.internal
  */
 public interface LocalNodeMasterListener extends ClusterStateListener {
 

server/src/main/java/org/opensearch/cluster/MasterNodeChangePredicate.java

@@ -36,6 +36,11 @@ import org.opensearch.cluster.node.DiscoveryNode;
 
 import java.util.function.Predicate;
 
+/**
+ * Utility class to build a predicate that accepts cluster state changes
+ *
+ * @opensearch.internal
+ */
 public final class MasterNodeChangePredicate {
 
     private MasterNodeChangePredicate() {

server/src/main/java/org/opensearch/cluster/MergableCustomMetadata.java

@@ -40,6 +40,8 @@ import org.opensearch.cluster.metadata.Metadata;
  * Custom metadata can be merged using {@link #merge(Metadata.Custom)}.
  *
  * @param <T> type of custom meta data
+ *
+ * @opensearch.internal
  */
 public interface MergableCustomMetadata<T extends Metadata.Custom> {
 

server/src/main/java/org/opensearch/cluster/NamedDiff.java

@@ -37,6 +37,8 @@ import org.opensearch.common.io.stream.NamedWriteable;
 
 /**
  * Diff that also support NamedWriteable interface
+ *
+ * @opensearch.internal
  */
 public interface NamedDiff<T extends Diffable<T>> extends Diff<T>, NamedWriteable {
     /**

server/src/main/java/org/opensearch/cluster/NamedDiffable.java

@@ -36,5 +36,7 @@ import org.opensearch.common.io.stream.VersionedNamedWriteable;
 
 /**
  * Diff that also support {@link VersionedNamedWriteable} interface
+ *
+ * @opensearch.internal
  */
 public interface NamedDiffable<T> extends Diffable<T>, VersionedNamedWriteable {}

server/src/main/java/org/opensearch/cluster/NamedDiffableValueSerializer.java

@@ -39,6 +39,8 @@ import java.io.IOException;
 
 /**
  * Value Serializer for named diffables
+ *
+ * @opensearch.internal
  */
 public class NamedDiffableValueSerializer<T extends NamedDiffable<T>> extends DiffableUtils.DiffableValueSerializer<String, T> {
 

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

@@ -80,6 +80,8 @@ import static org.opensearch.common.settings.Setting.positiveTimeSetting;
  * <p>
  * This component does not block on disconnections at all, because a disconnection might need to wait for an ongoing (background) connection
  * attempt to complete first.
+ *
+ * @opensearch.internal
  */
 public class NodeConnectionsService extends AbstractLifecycleComponent {
     private static final Logger logger = LogManager.getLogger(NodeConnectionsService.class);

server/src/main/java/org/opensearch/cluster/NotMasterException.java

@@ -40,6 +40,8 @@ import java.io.IOException;
  * Thrown when a node join request or a cluster-manager ping reaches a node which is not
  * currently acting as a cluster-manager or when a cluster state update task is to be executed
  * on a node that is no longer cluster-manager.
+ *
+ * @opensearch.internal
  */
 public class NotMasterException extends OpenSearchException {
 

server/src/main/java/org/opensearch/cluster/RepositoryCleanupInProgress.java

@@ -45,6 +45,11 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+/**
+ * Information passed during repository cleanup
+ *
+ * @opensearch.internal
+ */
 public final class RepositoryCleanupInProgress extends AbstractNamedDiffable<ClusterState.Custom> implements ClusterState.Custom {
 
     public static final RepositoryCleanupInProgress EMPTY = new RepositoryCleanupInProgress(Collections.emptyList());

server/src/main/java/org/opensearch/cluster/RestoreInProgress.java

@@ -54,6 +54,8 @@ import java.util.UUID;
 
 /**
  * Meta data about restore processes that are currently executing
+ *
+ * @opensearch.internal
  */
 public class RestoreInProgress extends AbstractNamedDiffable<Custom> implements Custom, Iterable<RestoreInProgress.Entry> {
 

server/src/main/java/org/opensearch/cluster/SnapshotDeletionsInProgress.java

@@ -57,6 +57,8 @@ import java.util.Set;
 
 /**
  * A class that represents the snapshot deletions that are in progress in the cluster.
+ *
+ * @opensearch.internal
  */
 public class SnapshotDeletionsInProgress extends AbstractNamedDiffable<Custom> implements Custom {
 

server/src/main/java/org/opensearch/cluster/SnapshotsInProgress.java

@@ -71,6 +71,8 @@ import static org.opensearch.snapshots.SnapshotInfo.METADATA_FIELD_INTRODUCED;
 
 /**
  * Meta data about snapshots that are currently executing
+ *
+ * @opensearch.internal
  */
 public class SnapshotsInProgress extends AbstractNamedDiffable<Custom> implements Custom {
 

server/src/main/java/org/opensearch/cluster/TimeoutClusterStateListener.java

@@ -37,7 +37,7 @@ import org.opensearch.common.unit.TimeValue;
 /**
  * An exception to cluster state listener that allows for timeouts and for post added notifications.
  *
- *
+ * @opensearch.internal
  */
 public interface TimeoutClusterStateListener extends ClusterStateListener {
 

server/src/main/java/org/opensearch/cluster/ack/AckedRequest.java

@@ -36,6 +36,8 @@ import org.opensearch.common.unit.TimeValue;
 
 /**
  * Identifies a cluster state update request with acknowledgement support
+ *
+ * @opensearch.internal
  */
 public interface AckedRequest {
 

server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateRequest.java

@@ -37,6 +37,8 @@ import org.opensearch.common.unit.TimeValue;
 /**
  * Base class to be used when needing to update the cluster state
  * Contains the basic fields that are always needed
+ *
+ * @opensearch.internal
  */
 public abstract class ClusterStateUpdateRequest<T extends ClusterStateUpdateRequest<T>> implements AckedRequest {
 

server/src/main/java/org/opensearch/cluster/ack/ClusterStateUpdateResponse.java

@@ -34,6 +34,8 @@ package org.opensearch.cluster.ack;
 
 /**
  * Base response returned after a cluster state update
+ *
+ * @opensearch.internal
  */
 public class ClusterStateUpdateResponse {
 

server/src/main/java/org/opensearch/cluster/ack/CreateIndexClusterStateUpdateResponse.java

@@ -34,6 +34,8 @@ package org.opensearch.cluster.ack;
 
 /**
  * A cluster state update response with specific fields for index creation.
+ *
+ * @opensearch.internal
  */
 public class CreateIndexClusterStateUpdateResponse extends ClusterStateUpdateResponse {
 

server/src/main/java/org/opensearch/cluster/ack/IndicesClusterStateUpdateRequest.java

@@ -35,6 +35,8 @@ import org.opensearch.index.Index;
 
 /**
  * Base cluster state update request that allows to execute update against multiple indices
+ *
+ * @opensearch.internal
  */
 public abstract class IndicesClusterStateUpdateRequest<T extends IndicesClusterStateUpdateRequest<T>> extends ClusterStateUpdateRequest<T> {
 

server/src/main/java/org/opensearch/cluster/ack/OpenIndexClusterStateUpdateResponse.java

@@ -33,6 +33,8 @@ package org.opensearch.cluster.ack;
 
 /**
  * A cluster state update response with specific fields for index opening.
+ *
+ * @opensearch.internal
  */
 public class OpenIndexClusterStateUpdateResponse extends ClusterStateUpdateResponse {
 

server/src/main/java/org/opensearch/cluster/action/index/MappingUpdatedAction.java

@@ -58,6 +58,8 @@ import java.util.concurrent.Semaphore;
 /**
  * Called by shards in the cluster when their mapping was dynamically updated and it needs to be updated
  * in the cluster state meta data (and broadcast to all members).
+ *
+ * @opensearch.internal
  */
 public class MappingUpdatedAction {
 

server/src/main/java/org/opensearch/cluster/action/index/NodeMappingRefreshAction.java

@@ -53,6 +53,11 @@ import org.opensearch.transport.TransportService;
 
 import java.io.IOException;
 
+/**
+ * Transport action for refreshing the Node Mapping
+ *
+ * @opensearch.internal
+ */
 public class NodeMappingRefreshAction {
 
     private static final Logger logger = LogManager.getLogger(NodeMappingRefreshAction.class);

server/src/main/java/org/opensearch/cluster/action/shard/ShardStateAction.java

@@ -87,6 +87,11 @@ import java.util.Set;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+/**
+ * Transport action for retrieving the shard state
+ *
+ * @opensearch.internal
+ */
 public class ShardStateAction {
 
     private static final Logger logger = LogManager.getLogger(ShardStateAction.class);

server/src/main/java/org/opensearch/cluster/block/ClusterBlock.java

@@ -45,6 +45,11 @@ import java.util.EnumSet;
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * Blocks the cluster for concurrency
+ *
+ * @opensearch.internal
+ */
 public class ClusterBlock implements Writeable, ToXContentFragment {
 
     private final int id;

server/src/main/java/org/opensearch/cluster/block/ClusterBlockException.java

@@ -46,6 +46,11 @@ import java.util.stream.Collectors;
 
 import static java.util.Collections.unmodifiableSet;
 
+/**
+ * Internal exception on obtaining a cluster block
+ *
+ * @opensearch.internal
+ */
 public class ClusterBlockException extends OpenSearchException {
     private final Set<ClusterBlock> blocks;
 

server/src/main/java/org/opensearch/cluster/block/ClusterBlockLevel.java

@@ -34,6 +34,11 @@ package org.opensearch.cluster.block;
 
 import java.util.EnumSet;
 
+/**
+ * What level to block the cluster
+ *
+ * @opensearch.internal
+ */
 public enum ClusterBlockLevel {
     READ,
     WRITE,

server/src/main/java/org/opensearch/cluster/block/ClusterBlocks.java

@@ -59,6 +59,8 @@ import static java.util.stream.Collectors.toSet;
 
 /**
  * Represents current cluster level blocks to block dirty operations done against the cluster.
+ *
+ * @opensearch.internal
  */
 public class ClusterBlocks extends AbstractDiffable<ClusterBlocks> {
     public static final ClusterBlocks EMPTY_CLUSTER_BLOCK = new ClusterBlocks(emptySet(), ImmutableOpenMap.of());

server/src/main/java/org/opensearch/cluster/coordination/ApplyCommitRequest.java

@@ -41,6 +41,8 @@ import java.io.IOException;
  * A cluster-manager node sends this request to its peers to inform them that it could commit the
  * cluster state with the given term and version. Peers that have accepted the given cluster
  * state will then consider it as committed and proceed to apply the state locally.
+ *
+ * @opensearch.internal
  */
 public class ApplyCommitRequest extends TermVersionRequest {
 

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

@@ -69,6 +69,11 @@ import static org.opensearch.discovery.DiscoveryModule.LEGACY_DISCOVERY_HOSTS_PR
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.DISCOVERY_SEED_HOSTS_SETTING;
 import static org.opensearch.discovery.SettingsBasedSeedHostsProvider.LEGACY_DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 
+/**
+ * Service for bootstrapping the OpenSearch cluster
+ *
+ * @opensearch.internal
+ */
 public class ClusterBootstrapService {
 
     public static final Setting<List<String>> INITIAL_MASTER_NODES_SETTING = Setting.listSetting(

server/src/main/java/org/opensearch/cluster/coordination/ClusterFormationFailureHelper.java

@@ -59,6 +59,11 @@ import java.util.stream.StreamSupport;
 import static org.opensearch.cluster.coordination.ClusterBootstrapService.INITIAL_CLUSTER_MANAGER_NODES_SETTING;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Helper for cluster failure events
+ *
+ * @opensearch.internal
+ */
 public class ClusterFormationFailureHelper {
     private static final Logger logger = LogManager.getLogger(ClusterFormationFailureHelper.class);
 

server/src/main/java/org/opensearch/cluster/coordination/ClusterStatePublisher.java

@@ -37,6 +37,11 @@ import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.unit.TimeValue;
 
+/**
+ * Publishes the cluster state
+ *
+ * @opensearch.internal
+ */
 public interface ClusterStatePublisher {
     /**
      * Publish all the changes to the cluster from the cluster-manager (can be called just by the cluster-manager). The publish

server/src/main/java/org/opensearch/cluster/coordination/CoordinationMetadata.java

@@ -52,6 +52,11 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
+/**
+ * Metadata for cluster coordination
+ *
+ * @opensearch.internal
+ */
 public class CoordinationMetadata implements Writeable, ToXContentFragment {
 
     public static final CoordinationMetadata EMPTY_METADATA = builder().build();

server/src/main/java/org/opensearch/cluster/coordination/CoordinationState.java

@@ -53,6 +53,8 @@ import static org.opensearch.cluster.coordination.Coordinator.ZEN1_BWC_TERM;
 /**
  * The core class of the cluster state coordination algorithm, directly implementing the
  * <a href="https://github.com/elastic/elasticsearch-formal-models/blob/master/ZenWithTerms/tla/ZenWithTerms.tla">formal model</a>
+ *
+ * @opensearch.internal
  */
 public class CoordinationState {
 

server/src/main/java/org/opensearch/cluster/coordination/CoordinationStateRejectedException.java

@@ -43,6 +43,8 @@ import java.io.IOException;
  * Occurrences of this exception don't always signal failures, but can often be just caused by the
  * asynchronous, distributed nature of the system. They will, for example, naturally happen during
  * leader election, if multiple nodes are trying to become leader at the same time.
+ *
+ * @opensearch.internal
  */
 public class CoordinationStateRejectedException extends OpenSearchException {
     public CoordinationStateRejectedException(String msg, Object... args) {

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

@@ -110,6 +110,11 @@ import static org.opensearch.gateway.ClusterStateUpdaters.hideStateIfNotRecovere
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * The main lifecycle resource coordinator
+ *
+ * @opensearch.internal
+ */
 public class Coordinator extends AbstractLifecycleComponent implements Discovery {
 
     public static final long ZEN1_BWC_TERM = 0;

server/src/main/java/org/opensearch/cluster/coordination/DetachClusterCommand.java

@@ -41,6 +41,11 @@ import org.opensearch.gateway.PersistedClusterStateService;
 import java.io.IOException;
 import java.nio.file.Path;
 
+/**
+ * Command to detach a node from the cluster
+ *
+ * @opensearch.internal
+ */
 public class DetachClusterCommand extends OpenSearchNodeCommand {
 
     static final String NODE_DETACHED_MSG = "Node was successfully detached from the cluster";

server/src/main/java/org/opensearch/cluster/coordination/ElectionSchedulerFactory.java

@@ -56,6 +56,8 @@ import java.util.concurrent.atomic.AtomicLong;
  * randomly at reasonably high frequency and backing off (linearly) until one of them succeeds. We also place an upper bound on the backoff
  * so that if elections are failing due to a network partition that lasts for a long time then when the partition heals there is an election
  * attempt reasonably quickly.
+ *
+ * @opensearch.internal
  */
 public class ElectionSchedulerFactory {
 

server/src/main/java/org/opensearch/cluster/coordination/ElectionStrategy.java

@@ -38,6 +38,8 @@ import org.opensearch.cluster.node.DiscoveryNode;
 /**
  * Allows plugging in a custom election strategy, restricting the notion of an election quorum.
  * Custom additional quorum restrictions can be defined by implementing the {@link #satisfiesAdditionalQuorumConstraints} method.
+ *
+ * @opensearch.internal
  */
 public abstract class ElectionStrategy {
 

server/src/main/java/org/opensearch/cluster/coordination/FailedToCommitClusterStateException.java

@@ -38,6 +38,8 @@ import java.io.IOException;
 
 /**
  * Thrown when failing to publish a cluster state. See {@link ClusterStatePublisher} for more details.
+ *
+ * @opensearch.internal
  */
 public class FailedToCommitClusterStateException extends OpenSearchException {
 

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

@@ -76,6 +76,8 @@ import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
  * follower has failed the leader will remove it from the cluster. We are fairly lenient, possibly allowing multiple checks to fail before
  * considering a follower to be faulty, to allow for a brief network partition or a long GC cycle to occur without triggering the removal of
  * a node and the consequent shard reallocation.
+ *
+ * @opensearch.internal
  */
 public class FollowersChecker {
 

server/src/main/java/org/opensearch/cluster/coordination/InMemoryPersistedState.java

@@ -33,6 +33,11 @@ package org.opensearch.cluster.coordination;
 
 import org.opensearch.cluster.ClusterState;
 
+/**
+ * Persist state in memory
+ *
+ * @opensearch.internal
+ */
 public class InMemoryPersistedState implements CoordinationState.PersistedState {
 
     private long currentTerm;

server/src/main/java/org/opensearch/cluster/coordination/Join.java

@@ -46,6 +46,8 @@ import java.io.IOException;
  * information about the current state of the node that provided the vote, so that
  * the receiver of the vote can determine if it has a more up-to-date state than the
  * source node.
+ *
+ * @opensearch.internal
  */
 public class Join implements Writeable {
     private final DiscoveryNode sourceNode;

server/src/main/java/org/opensearch/cluster/coordination/JoinHelper.java

@@ -84,6 +84,11 @@ import java.util.function.Supplier;
 
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Helper utility class for joining the cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinHelper {
 
     private static final Logger logger = LogManager.getLogger(JoinHelper.class);

server/src/main/java/org/opensearch/cluster/coordination/JoinRequest.java

@@ -41,6 +41,11 @@ import java.io.IOException;
 import java.util.Objects;
 import java.util.Optional;
 
+/**
+ * Request for a node to join the cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinRequest extends TransportRequest {
 
     /**

server/src/main/java/org/opensearch/cluster/coordination/JoinTaskExecutor.java

@@ -62,6 +62,11 @@ import java.util.stream.Collectors;
 
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
 
+/**
+ * Main executor for Nodes joining the OpenSearch cluster
+ *
+ * @opensearch.internal
+ */
 public class JoinTaskExecutor implements ClusterStateTaskExecutor<JoinTaskExecutor.Task> {
 
     private final AllocationService allocationService;

server/src/main/java/org/opensearch/cluster/coordination/LagDetector.java

@@ -56,6 +56,8 @@ import static org.opensearch.common.util.concurrent.ConcurrentCollections.newCon
  * A publication can succeed and complete before all nodes have applied the published state and acknowledged it; however we need every node
  * eventually either to apply the published state (or a later state) or be removed from the cluster. This component achieves this by
  * removing any lagging nodes from the cluster after a timeout.
+ *
+ * @opensearch.internal
  */
 public class LagDetector {
 

server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java

@@ -75,6 +75,8 @@ import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
  * fairly lenient, possibly allowing multiple checks to fail before considering the leader to be faulty, to allow for the leader to
  * temporarily stand down on occasion, e.g. if it needs to move to a higher term. On deciding that the leader has failed a follower will
  * become a candidate and attempt to become a leader itself.
+ *
+ * @opensearch.internal
  */
 public class LeaderChecker {
 

server/src/main/java/org/opensearch/cluster/coordination/NoMasterBlockService.java

@@ -41,6 +41,11 @@ import org.opensearch.rest.RestStatus;
 
 import java.util.EnumSet;
 
+/**
+ * Service to block the master node
+ *
+ * @opensearch.internal
+ */
 public class NoMasterBlockService {
     public static final int NO_MASTER_BLOCK_ID = 2;
     public static final ClusterBlock NO_MASTER_BLOCK_WRITES = new ClusterBlock(

server/src/main/java/org/opensearch/cluster/coordination/NodeHealthCheckFailureException.java

@@ -40,6 +40,8 @@ import java.io.IOException;
 /**
  * This exception is thrown if the File system is reported unhealthy by @{@link org.opensearch.monitor.fs.FsHealthService}
  * and this nodes needs to be removed from the cluster
+ *
+ * @opensearch.internal
  */
 
 public class NodeHealthCheckFailureException extends OpenSearchException {

server/src/main/java/org/opensearch/cluster/coordination/NodeRemovalClusterStateTaskExecutor.java

@@ -43,6 +43,11 @@ import org.opensearch.persistent.PersistentTasksCustomMetadata;
 
 import java.util.List;
 
+/**
+ * Update cluster state when node is removed from the cluster
+ *
+ * @opensearch.internal
+ */
 public class NodeRemovalClusterStateTaskExecutor
     implements
         ClusterStateTaskExecutor<NodeRemovalClusterStateTaskExecutor.Task>,

server/src/main/java/org/opensearch/cluster/coordination/NodeToolCli.java

@@ -44,6 +44,12 @@ import org.opensearch.env.OverrideNodeVersionCommand;
 // Even if we avoid making a static reference to Logger class, there is no nice way to avoid declaring
 // UNSAFE_BOOTSTRAP, which depends on ClusterService, which in turn has static Logger.
 // TODO execute CommandLoggingConfigurator.configureLoggingWithoutConfig() in the constructor of commands, not in beforeMain
+
+/**
+ * Command Line Interface tool for Nodes
+ *
+ * @opensearch.internal
+ */
 public class NodeToolCli extends MultiCommand {
 
     public NodeToolCli() {

server/src/main/java/org/opensearch/cluster/coordination/OpenSearchNodeCommand.java

@@ -70,6 +70,11 @@ import java.util.EnumSet;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Main set of node commands
+ *
+ * @opensearch.internal
+ */
 public abstract class OpenSearchNodeCommand extends EnvironmentAwareCommand {
     private static final Logger logger = LogManager.getLogger(OpenSearchNodeCommand.class);
     protected static final String DELIMITER = "------------------------------------------------------------------------\n";

server/src/main/java/org/opensearch/cluster/coordination/PeersResponse.java

@@ -42,6 +42,11 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
+/**
+ * Response from peer nodes
+ *
+ * @opensearch.internal
+ */
 public class PeersResponse extends TransportResponse {
     private final Optional<DiscoveryNode> clusterManagerNode;
     private final List<DiscoveryNode> knownPeers;

server/src/main/java/org/opensearch/cluster/coordination/PendingClusterStateStats.java

@@ -42,6 +42,8 @@ import java.io.IOException;
 
 /**
  * Class encapsulating stats about the PendingClusterStatsQueue
+ *
+ * @opensearch.internal
  */
 public class PendingClusterStateStats implements Writeable, ToXContentFragment {
 

server/src/main/java/org/opensearch/cluster/coordination/PreVoteCollector.java

@@ -58,6 +58,11 @@ import java.util.stream.StreamSupport;
 import static org.opensearch.common.util.concurrent.ConcurrentCollections.newConcurrentMap;
 import static org.opensearch.monitor.StatusInfo.Status.UNHEALTHY;
 
+/**
+ * Collects information prior to a promotion vote
+ *
+ * @opensearch.internal
+ */
 public class PreVoteCollector {
 
     private static final Logger logger = LogManager.getLogger(PreVoteCollector.class);

server/src/main/java/org/opensearch/cluster/coordination/PreVoteRequest.java

@@ -40,6 +40,11 @@ import org.opensearch.transport.TransportRequest;
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Requests pre vote information collection
+ *
+ * @opensearch.internal
+ */
 public class PreVoteRequest extends TransportRequest {
 
     private final DiscoveryNode sourceNode;

server/src/main/java/org/opensearch/cluster/coordination/PreVoteResponse.java

@@ -39,6 +39,11 @@ import org.opensearch.transport.TransportResponse;
 import java.io.IOException;
 import java.util.Objects;
 
+/**
+ * Response for a PreVoteRequest
+ *
+ * @opensearch.internal
+ */
 public class PreVoteResponse extends TransportResponse {
     private final long currentTerm;
     private final long lastAcceptedTerm;

server/src/main/java/org/opensearch/cluster/coordination/Publication.java

@@ -52,6 +52,11 @@ import java.util.Set;
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
 
+/**
+ * Publication task
+ *
+ * @opensearch.internal
+ */
 public abstract class Publication {
 
     protected final Logger logger = LogManager.getLogger(getClass());

server/src/main/java/org/opensearch/cluster/coordination/PublicationTransportHandler.java

@@ -72,6 +72,11 @@ import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+/**
+ * Transport handler for publication
+ *
+ * @opensearch.internal
+ */
 public class PublicationTransportHandler {
 
     private static final Logger logger = LogManager.getLogger(PublicationTransportHandler.class);

server/src/main/java/org/opensearch/cluster/coordination/PublishClusterStateStats.java

@@ -42,6 +42,8 @@ import java.io.IOException;
 
 /**
  * Class encapsulating stats about the PublishClusterStateAction
+ *
+ * @opensearch.internal
  */
 public class PublishClusterStateStats implements Writeable, ToXContentObject {
 

server/src/main/java/org/opensearch/cluster/coordination/PublishRequest.java

@@ -38,6 +38,8 @@ import java.util.Objects;
 /**
  * Request which is used by the cluster-manager node to publish cluster state changes.
  * Actual serialization of this request is done by {@link PublicationTransportHandler}
+ *
+ * @opensearch.internal
  */
 public class PublishRequest {
 

server/src/main/java/org/opensearch/cluster/coordination/PublishResponse.java

@@ -40,6 +40,8 @@ import java.io.IOException;
 /**
  * Response to a {@link PublishRequest}, carrying the term and version of the request.
  * Typically wrapped in a {@link PublishWithJoinResponse}.
+ *
+ * @opensearch.internal
  */
 public class PublishResponse implements Writeable {
 

server/src/main/java/org/opensearch/cluster/coordination/PublishWithJoinResponse.java

@@ -41,6 +41,8 @@ import java.util.Optional;
 /**
  * Response to a {@link PublishRequest}. Encapsulates both a {@link PublishResponse}
  * and an optional {@link Join}.
+ *
+ * @opensearch.internal
  */
 public class PublishWithJoinResponse extends TransportResponse {
     private final PublishResponse publishResponse;

server/src/main/java/org/opensearch/cluster/coordination/Reconfigurator.java

@@ -47,6 +47,8 @@ import java.util.stream.Collectors;
 
 /**
  * Computes the optimal configuration of voting nodes in the cluster.
+ *
+ * @opensearch.internal
  */
 public class Reconfigurator {
 

server/src/main/java/org/opensearch/cluster/coordination/RemoveCustomsCommand.java

@@ -48,6 +48,11 @@ import java.io.IOException;
 import java.nio.file.Path;
 import java.util.List;
 
+/**
+ * Removes custom metadata
+ *
+ * @opensearch.internal
+ */
 public class RemoveCustomsCommand extends OpenSearchNodeCommand {
 
     static final String CUSTOMS_REMOVED_MSG = "Customs were successfully removed from the cluster state";

server/src/main/java/org/opensearch/cluster/coordination/RemoveSettingsCommand.java

@@ -48,6 +48,11 @@ import java.io.IOException;
 import java.nio.file.Path;
 import java.util.List;
 
+/**
+ * Removes custom settings
+ *
+ * @opensearch.internal
+ */
 public class RemoveSettingsCommand extends OpenSearchNodeCommand {
 
     static final String SETTINGS_REMOVED_MSG = "Settings were successfully removed from the cluster state";

server/src/main/java/org/opensearch/cluster/coordination/StartJoinRequest.java

@@ -41,6 +41,8 @@ import java.io.IOException;
 /**
  * Represents the action of requesting a join vote (see {@link Join}) from a node.
  * The source node represents the node that is asking for join votes.
+ *
+ * @opensearch.internal
  */
 public class StartJoinRequest extends TransportRequest {
 

server/src/main/java/org/opensearch/cluster/coordination/TermVersionRequest.java

@@ -39,6 +39,11 @@ import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Get's the version of a term
+ *
+ * @opensearch.internal
+ */
 abstract class TermVersionRequest extends TransportRequest implements Writeable {
     protected final DiscoveryNode sourceNode;
     protected final long term;

server/src/main/java/org/opensearch/cluster/coordination/UnsafeBootstrapMasterCommand.java

@@ -54,6 +54,11 @@ import java.util.Collections;
 import java.util.Locale;
 import java.util.Objects;
 
+/**
+ * Tool to run an unsafe bootstrap
+ *
+ * @opensearch.internal
+ */
 public class UnsafeBootstrapMasterCommand extends OpenSearchNodeCommand {
 
     static final String CLUSTER_STATE_TERM_VERSION_MSG_FORMAT = "Current node cluster state (term, version) pair is (%s, %s)";

server/src/main/java/org/opensearch/cluster/coordination/ValidateJoinRequest.java

@@ -38,6 +38,11 @@ import org.opensearch.transport.TransportRequest;
 
 import java.io.IOException;
 
+/**
+ * Transport request to validate node join
+ *
+ * @opensearch.internal
+ */
 public class ValidateJoinRequest extends TransportRequest {
     private ClusterState state;
 

server/src/main/java/org/opensearch/cluster/health/ClusterHealthStatus.java

@@ -38,6 +38,11 @@ import org.opensearch.common.io.stream.Writeable;
 
 import java.io.IOException;
 
+/**
+ * Cluster health status
+ *
+ * @opensearch.internal
+ */
 public enum ClusterHealthStatus implements Writeable {
     GREEN((byte) 0),
     YELLOW((byte) 1),

server/src/main/java/org/opensearch/cluster/health/ClusterIndexHealth.java

@@ -58,6 +58,11 @@ import static org.opensearch.common.xcontent.ConstructingObjectParser.constructo
 import static org.opensearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
 import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Cluster Index Health Information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterIndexHealth implements Iterable<ClusterShardHealth>, Writeable, ToXContentFragment {
     private static final String STATUS = "status";
     private static final String NUMBER_OF_SHARDS = "number_of_shards";

server/src/main/java/org/opensearch/cluster/health/ClusterShardHealth.java

@@ -54,6 +54,11 @@ import java.util.Objects;
 import static org.opensearch.common.xcontent.ConstructingObjectParser.constructorArg;
 import static org.opensearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
 
+/**
+ * Cluster shard health information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterShardHealth implements Writeable, ToXContentFragment {
     private static final String STATUS = "status";
     private static final String ACTIVE_SHARDS = "active_shards";

server/src/main/java/org/opensearch/cluster/health/ClusterStateHealth.java

@@ -49,6 +49,11 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
+/**
+ * Cluster state health information
+ *
+ * @opensearch.internal
+ */
 public final class ClusterStateHealth implements Iterable<ClusterIndexHealth>, Writeable {
 
     private final int numberOfNodes;

server/src/main/java/org/opensearch/cluster/metadata/AliasAction.java

@@ -38,6 +38,8 @@ import org.opensearch.common.Strings;
 
 /**
  * Individual operation to perform on the cluster state as part of an {@link IndicesAliasesRequest}.
+ *
+ * @opensearch.internal
  */
 public abstract class AliasAction {
     private final String index;

server/src/main/java/org/opensearch/cluster/metadata/AliasMetadata.java

@@ -58,6 +58,11 @@ import java.util.Set;
 
 import static java.util.Collections.emptySet;
 
+/**
+ * Metadata for index aliases
+ *
+ * @opensearch.internal
+ */
 public class AliasMetadata extends AbstractDiffable<AliasMetadata> implements ToXContentFragment {
 
     private final String alias;