[Remote Store] Introducing mixed mode support for remote store migration

CHANGELOG.md

@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Allow to pass the list settings through environment variables (like [], ["a", "b", "c"], ...) ([#10625](https://github.com/opensearch-project/OpenSearch/pull/10625))
 - [Admission Control] Integrate CPU AC with ResourceUsageCollector and add CPU AC stats to nodes/stats ([#10887](https://github.com/opensearch-project/OpenSearch/pull/10887))
 - [S3 Repository] Add setting to control connection count for sync client ([#12028](https://github.com/opensearch-project/OpenSearch/pull/12028))
+- Add Remote Store Migration Experimental flag and allow mixed mode clusters under same ([#11986](https://github.com/opensearch-project/OpenSearch/pull/11986))
 
 ### Dependencies
 - Bump `log4j-core` from 2.18.0 to 2.19.0

server/src/internalClusterTest/java/org/opensearch/remotemigration/DocRepMigrationTestCase.java

@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotemigration;
+
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class DocRepMigrationTestCase extends MigrationBaseTestCase {
+
+    public void testMixedModeAddDocRep() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        List<String> cmNodes = internalCluster().startNodes(1);
+
+        Client client = internalCluster().client(cmNodes.get(0));
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        updateSettingsRequest.persistentSettings(Settings.builder().put(REMOTE_STORE_COMPATIBILITY_MODE_SETTING.getKey(), "mixed"));
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+        addRemote = false;
+        internalCluster().startNode();
+        String[] allNodes = internalCluster().getNodeNames();
+        assertBusy(() -> { assertEquals(client.admin().cluster().prepareClusterStats().get().getNodes().size(), allNodes.length); });
+    }
+
+}

server/src/internalClusterTest/java/org/opensearch/remotemigration/MigrationBaseTestCase.java

@@ -0,0 +1,50 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotemigration;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.nio.file.Path;
+
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+
+public class MigrationBaseTestCase extends OpenSearchIntegTestCase {
+    protected static final String REPOSITORY_NAME = "test-remote-store-repo";
+    protected static final String REPOSITORY_2_NAME = "test-remote-store-repo-2";
+
+    protected Path segmentRepoPath;
+    protected Path translogRepoPath;
+
+    boolean addRemote = false;
+
+    protected Settings nodeSettings(int nodeOrdinal) {
+        if (segmentRepoPath == null || translogRepoPath == null) {
+            segmentRepoPath = randomRepoPath().toAbsolutePath();
+            translogRepoPath = randomRepoPath().toAbsolutePath();
+        }
+        if (addRemote) {
+            logger.info("Adding remote store node");
+            return Settings.builder()
+                .put(super.nodeSettings(nodeOrdinal))
+                .put(remoteStoreClusterSettings(REPOSITORY_NAME, segmentRepoPath, REPOSITORY_2_NAME, translogRepoPath))
+                .put("discovery.initial_state_timeout", "500ms")
+                .build();
+        } else {
+            logger.info("Adding docrep node");
+            return Settings.builder().put(super.nodeSettings(nodeOrdinal)).put("discovery.initial_state_timeout", "500ms").build();
+        }
+    }
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.REMOTE_STORE_MIGRATION_EXPERIMENTAL, "true").build();
+    }
+}

server/src/internalClusterTest/java/org/opensearch/remotemigration/RemoteStoreMigrationTestCase.java

@@ -0,0 +1,74 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.remotemigration;
+
+import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesRequest;
+import org.opensearch.action.admin.cluster.repositories.get.GetRepositoriesResponse;
+import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
+import org.opensearch.client.Client;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.MIGRATION_DIRECTION_SETTING;
+import static org.opensearch.node.remotestore.RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING;
+import static org.opensearch.remotestore.RemoteStoreBaseIntegTestCase.remoteStoreClusterSettings;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
+public class RemoteStoreMigrationTestCase extends MigrationBaseTestCase {
+    public void testMixedModeAddRemoteNodes() throws Exception {
+        internalCluster().setBootstrapClusterManagerNodeIndex(0);
+        List<String> cmNodes = internalCluster().startNodes(1);
+        Client client = internalCluster().client(cmNodes.get(0));
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        updateSettingsRequest.persistentSettings(Settings.builder().put(REMOTE_STORE_COMPATIBILITY_MODE_SETTING.getKey(), "mixed"));
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+
+        // add remote node in mixed mode cluster
+        addRemote = true;
+        internalCluster().startNode();
+        internalCluster().startNode();
+        internalCluster().validateClusterFormed();
+
+        // assert repo gets registered
+        GetRepositoriesRequest gr = new GetRepositoriesRequest(new String[] { REPOSITORY_NAME });
+        GetRepositoriesResponse getRepositoriesResponse = client.admin().cluster().getRepositories(gr).actionGet();
+        assertEquals(1, getRepositoriesResponse.repositories().size());
+
+        // add docrep mode in mixed mode cluster
+        addRemote = true;
+        internalCluster().startNode();
+        assertBusy(() -> {
+            assertEquals(client.admin().cluster().prepareClusterStats().get().getNodes().size(), internalCluster().getNodeNames().length);
+        });
+
+        // add incompatible remote node in remote mixed cluster
+        Settings.Builder badSettings = Settings.builder()
+            .put(remoteStoreClusterSettings(REPOSITORY_NAME, segmentRepoPath, "REPOSITORY_2_NAME", translogRepoPath))
+            .put("discovery.initial_state_timeout", "500ms");
+        String badNode = internalCluster().startNode(badSettings);
+        assertTrue(client.admin().cluster().prepareClusterStats().get().getNodes().size() < internalCluster().getNodeNames().length);
+        internalCluster().stopRandomNode(settings -> settings.get("node.name").equals(badNode));
+    }
+
+    public void testMigrationDirections() {
+        ClusterUpdateSettingsRequest updateSettingsRequest = new ClusterUpdateSettingsRequest();
+        // add remote node in docrep cluster
+        updateSettingsRequest.persistentSettings(Settings.builder().put(MIGRATION_DIRECTION_SETTING.getKey(), "docrep"));
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+
+        updateSettingsRequest.persistentSettings(Settings.builder().put(MIGRATION_DIRECTION_SETTING.getKey(), "remote_store"));
+        assertAcked(client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+
+        updateSettingsRequest.persistentSettings(Settings.builder().put(MIGRATION_DIRECTION_SETTING.getKey(), "random"));
+        assertThrows(IllegalArgumentException.class, () -> client().admin().cluster().updateSettings(updateSettingsRequest).actionGet());
+    }
+}

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

@@ -58,6 +58,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
@@ -176,12 +177,13 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
 
         DiscoveryNodes.Builder nodesBuilder = DiscoveryNodes.builder(newState.nodes());
 
-        // TODO: We are using one of the existing node to build the repository metadata, this will need to be updated
-        // once we start supporting mixed compatibility mode. An optimization can be done as this will get invoked
+        // An optimization can be done as this will get invoked
         // for every set of node join task which we can optimize to not compute if cluster state already has
         // repository information.
+        Optional<DiscoveryNode> remoteDN = currentNodes.getNodes().values().stream().filter(DiscoveryNode::isRemoteStoreNode).findFirst();
+        DiscoveryNode dn = remoteDN.orElseGet(() -> (currentNodes.getNodes().values()).stream().findFirst().get());
         RepositoriesMetadata repositoriesMetadata = remoteStoreNodeService.updateRepositoriesMetadata(
-            (currentNodes.getNodes().values()).stream().findFirst().get(),
+            dn,
             currentState.getMetadata().custom(RepositoriesMetadata.TYPE)
         );
 
@@ -212,6 +214,16 @@ public ClusterTasksResult<Task> execute(ClusterState currentState, List<Task> jo
                     // would guarantee that a decommissioned node would never be able to join the cluster and ensures correctness
                     ensureNodeCommissioned(node, currentState.metadata());
                     nodesBuilder.add(node);
+
+                    if (remoteDN.isEmpty()) {
+                        // This is hit only on cases where we encounter first remote node
+                        logger.info("Updating system repository now for remote store");
+                        repositoriesMetadata = remoteStoreNodeService.updateRepositoriesMetadata(
+                            node,
+                            currentState.getMetadata().custom(RepositoriesMetadata.TYPE)
+                        );
+                    }
+
                     nodesChanged = true;
                     minClusterNodeVersion = Version.min(minClusterNodeVersion, node.getVersion());
                     maxClusterNodeVersion = Version.max(maxClusterNodeVersion, node.getVersion());
@@ -495,36 +507,46 @@ private static void ensureRemoteStoreNodesCompatibility(DiscoveryNode joiningNod
 
         assert existingNodes.isEmpty() == false;
 
-        // TODO: The below check is valid till we don't support migration, once we start supporting migration a remote
-        // store node will be able to join a non remote store cluster and vice versa. #7986
         CompatibilityMode remoteStoreCompatibilityMode = REMOTE_STORE_COMPATIBILITY_MODE_SETTING.get(metadata.settings());
         if (STRICT.equals(remoteStoreCompatibilityMode)) {
+
             DiscoveryNode existingNode = existingNodes.get(0);
             if (joiningNode.isRemoteStoreNode()) {
+                ensureRemoteStoreNodesCompatibility(joiningNode, existingNode);
+            } else {
                 if (existingNode.isRemoteStoreNode()) {
-                    RemoteStoreNodeAttribute joiningRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(joiningNode);
-                    RemoteStoreNodeAttribute existingRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(existingNode);
-                    if (existingRemoteStoreNodeAttribute.equals(joiningRemoteStoreNodeAttribute) == false) {
-                        throw new IllegalStateException(
-                            "a remote store node ["
-                                + joiningNode
-                                + "] is trying to join a remote store cluster with incompatible node attributes in "
-                                + "comparison with existing node ["
-                                + existingNode
-                                + "]"
-                        );
-                    }
-                } else {
                     throw new IllegalStateException(
-                        "a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"
+                        "a non remote store node [" + joiningNode + "] is trying to join a remote store cluster"
                     );
                 }
-            } else {
-                if (existingNode.isRemoteStoreNode()) {
+            }
+        } else {
+            if (remoteStoreCompatibilityMode == CompatibilityMode.MIXED) {
+                if (joiningNode.isRemoteStoreNode()) {
+                    Optional<DiscoveryNode> remoteDN = existingNodes.stream().filter(DiscoveryNode::isRemoteStoreNode).findFirst();
+                    remoteDN.ifPresent(discoveryNode -> ensureRemoteStoreNodesCompatibility(joiningNode, discoveryNode));
+                }
+            }
+        }
+    }
+
+    private static void ensureRemoteStoreNodesCompatibility(DiscoveryNode joiningNode, DiscoveryNode existingNode) {
+        if (joiningNode.isRemoteStoreNode()) {
+            if (existingNode.isRemoteStoreNode()) {
+                RemoteStoreNodeAttribute joiningRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(joiningNode);
+                RemoteStoreNodeAttribute existingRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(existingNode);
+                if (existingRemoteStoreNodeAttribute.equals(joiningRemoteStoreNodeAttribute) == false) {
                     throw new IllegalStateException(
-                        "a non remote store node [" + joiningNode + "] is trying to join a remote store cluster"
+                        "a remote store node ["
+                            + joiningNode
+                            + "] is trying to join a remote store cluster with incompatible node attributes in "
+                            + "comparison with existing node ["
+                            + existingNode
+                            + "]"
                     );
                 }
+            } else {
+                throw new IllegalStateException("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster");
             }
         }
     }

server/src/main/java/org/opensearch/common/settings/ClusterSettings.java

@@ -698,6 +698,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 RemoteClusterStateService.GLOBAL_METADATA_UPLOAD_TIMEOUT_SETTING,
                 RemoteClusterStateService.METADATA_MANIFEST_UPLOAD_TIMEOUT_SETTING,
                 RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING,
+                RemoteStoreNodeService.MIGRATION_DIRECTION_SETTING,
                 IndicesService.CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING,
                 IndicesService.CLUSTER_REMOTE_INDEX_RESTRICT_ASYNC_DURABILITY_SETTING,
                 AdmissionControlSettings.ADMISSION_CONTROL_TRANSPORT_LAYER_MODE,

server/src/main/java/org/opensearch/common/settings/FeatureFlagSettings.java

@@ -35,6 +35,7 @@ protected FeatureFlagSettings(
         FeatureFlags.TELEMETRY_SETTING,
         FeatureFlags.DATETIME_FORMATTER_CACHING_SETTING,
         FeatureFlags.WRITEABLE_REMOTE_INDEX_SETTING,
-        FeatureFlags.DOC_ID_FUZZY_SET_SETTING
+        FeatureFlags.DOC_ID_FUZZY_SET_SETTING,
+        FeatureFlags.REMOTE_STORE_MIGRATION_EXPERIMENTAL_SETTING
     );
 }

server/src/main/java/org/opensearch/common/util/FeatureFlags.java

@@ -20,6 +20,11 @@
  * @opensearch.internal
  */
 public class FeatureFlags {
+    /**
+     * Gates the visibility of the remote store migration support from docrep .
+     */
+    public static final String REMOTE_STORE_MIGRATION_EXPERIMENTAL = "opensearch.experimental.feature.remote_store.migration.enabled";
+
     /**
      * Gates the ability for Searchable Snapshots to read snapshots that are older than the
      * guaranteed backward compatibility for OpenSearch (one prior major version) on a best effort basis.
@@ -98,6 +103,12 @@ public static boolean isEnabled(Setting<Boolean> featureFlag) {
         }
     }
 
+    public static final Setting<Boolean> REMOTE_STORE_MIGRATION_EXPERIMENTAL_SETTING = Setting.boolSetting(
+        REMOTE_STORE_MIGRATION_EXPERIMENTAL,
+        false,
+        Property.NodeScope
+    );
+
     public static final Setting<Boolean> EXTENSIONS_SETTING = Setting.boolSetting(EXTENSIONS, false, Property.NodeScope);
 
     public static final Setting<Boolean> IDENTITY_SETTING = Setting.boolSetting(IDENTITY, false, Property.NodeScope);