relaxing the join validation for nodes which have only store disabled but only publication enabled (opensearch-project#15471)

Signed-off-by: Rajiv Kumar Vaidyanathan <rajivkv@amazon.com>

Author: rajiv-kv

CHANGELOG.md

@@ -52,6 +52,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add canRemain method to TargetPoolAllocationDecider to move shards from local to remote pool for hot to warm tiering ([#15010](https://github.com/opensearch-project/OpenSearch/pull/15010))
 - ClusterManagerTaskThrottler Improvements ([#15508](https://github.com/opensearch-project/OpenSearch/pull/15508))
 - Reset DiscoveryNodes in all transport node actions request ([#15131](https://github.com/opensearch-project/OpenSearch/pull/15131))
+- Relax the join validation for Remote State publication ([#15471](https://github.com/opensearch-project/OpenSearch/pull/15471))
 
 ### Dependencies
 - Bump `netty` from 4.1.111.Final to 4.1.112.Final ([#15081](https://github.com/opensearch-project/OpenSearch/pull/15081))

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

@@ -67,6 +67,7 @@
 
 import static org.opensearch.cluster.decommission.DecommissionHelper.nodeCommissioned;
 import static org.opensearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_CLUSTER_PUBLICATION_REPO_NAME_ATTRIBUTES;
 import static org.opensearch.node.remotestore.RemoteStoreNodeService.CompatibilityMode;
 import static org.opensearch.node.remotestore.RemoteStoreNodeService.CompatibilityMode.MIXED;
 import static org.opensearch.node.remotestore.RemoteStoreNodeService.CompatibilityMode.STRICT;
@@ -458,7 +459,7 @@ public static void ensureNodesCompatibility(
             );
         }
 
-        ensureRemoteStoreNodesCompatibility(joiningNode, currentNodes, metadata);
+        ensureRemoteRepositoryCompatibility(joiningNode, currentNodes, metadata);
     }
 
     /**
@@ -491,6 +492,30 @@ public static void ensureNodeCommissioned(DiscoveryNode node, Metadata metadata)
         }
     }
 
+    public static void ensureRemoteRepositoryCompatibility(DiscoveryNode joiningNode, DiscoveryNodes currentNodes, Metadata metadata) {
+        List<DiscoveryNode> existingNodes = new ArrayList<>(currentNodes.getNodes().values());
+
+        boolean isClusterRemoteStoreEnabled = existingNodes.stream().anyMatch(DiscoveryNode::isRemoteStoreNode);
+        if (isClusterRemoteStoreEnabled || joiningNode.isRemoteStoreNode()) {
+            ensureRemoteStoreNodesCompatibility(joiningNode, currentNodes, metadata);
+        } else {
+            ensureRemoteClusterStateNodesCompatibility(joiningNode, currentNodes);
+        }
+    }
+
+    private static void ensureRemoteClusterStateNodesCompatibility(DiscoveryNode joiningNode, DiscoveryNodes currentNodes) {
+        List<DiscoveryNode> existingNodes = new ArrayList<>(currentNodes.getNodes().values());
+
+        assert existingNodes.isEmpty() == false;
+        Optional<DiscoveryNode> remotePublicationNode = existingNodes.stream()
+            .filter(DiscoveryNode::isRemoteStatePublicationEnabled)
+            .findFirst();
+
+        if (remotePublicationNode.isPresent() && joiningNode.isRemoteStatePublicationEnabled()) {
+            ensureRepositoryCompatibility(joiningNode, remotePublicationNode.get(), REMOTE_CLUSTER_PUBLICATION_REPO_NAME_ATTRIBUTES);
+        }
+    }
+
     /**
      * The method ensures homogeneity -
      * 1. The joining node has to be a remote store backed if it's joining a remote store backed cluster. Validates
@@ -506,6 +531,7 @@ public static void ensureNodeCommissioned(DiscoveryNode node, Metadata metadata)
      *       needs to be modified.
      */
     private static void ensureRemoteStoreNodesCompatibility(DiscoveryNode joiningNode, DiscoveryNodes currentNodes, Metadata metadata) {
+
         List<DiscoveryNode> existingNodes = new ArrayList<>(currentNodes.getNodes().values());
 
         assert existingNodes.isEmpty() == false;
@@ -587,6 +613,23 @@ private static void ensureRemoteStoreNodesCompatibility(
         }
     }
 
+    private static void ensureRepositoryCompatibility(DiscoveryNode joiningNode, DiscoveryNode existingNode, List<String> reposToValidate) {
+
+        RemoteStoreNodeAttribute joiningRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(joiningNode);
+        RemoteStoreNodeAttribute existingRemoteStoreNodeAttribute = new RemoteStoreNodeAttribute(existingNode);
+
+        if (existingRemoteStoreNodeAttribute.equalsForRepositories(joiningRemoteStoreNodeAttribute, reposToValidate) == 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
+                    + "]"
+            );
+        }
+    }
+
     public static Collection<BiConsumer<DiscoveryNode, ClusterState>> addBuiltInJoinValidators(
         Collection<BiConsumer<DiscoveryNode, ClusterState>> onJoinValidators
     ) {

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

@@ -184,6 +184,24 @@ public boolean equalsIgnoreGenerationsWithRepoSkip(@Nullable RepositoriesMetadat
             .filter(repo -> !reposToSkip.contains(repo.name()))
             .collect(Collectors.toList());
 
+        return equalsRepository(currentRepositories, otherRepositories);
+    }
+
+    public boolean equalsIgnoreGenerationsForRepo(@Nullable RepositoriesMetadata other, List<String> reposToValidate) {
+        if (other == null) {
+            return false;
+        }
+        List<RepositoryMetadata> currentRepositories = repositories.stream()
+            .filter(repo -> reposToValidate.contains(repo.name()))
+            .collect(Collectors.toList());
+        List<RepositoryMetadata> otherRepositories = other.repositories.stream()
+            .filter(repo -> reposToValidate.contains(repo.name()))
+            .collect(Collectors.toList());
+
+        return equalsRepository(currentRepositories, otherRepositories);
+    }
+
+    public static boolean equalsRepository(List<RepositoryMetadata> currentRepositories, List<RepositoryMetadata> otherRepositories) {
         if (otherRepositories.size() != currentRepositories.size()) {
             return false;
         }

server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java

@@ -65,6 +65,7 @@
 import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
 import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX;
 import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_ROUTING_TABLE_REPOSITORY_NAME_ATTRIBUTE_KEY;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
 
 /**
  * A discovery node represents a node that is part of the cluster.
@@ -509,7 +510,8 @@ public boolean isSearchNode() {
      * @return true if the node contains remote store node attributes, false otherwise
      */
     public boolean isRemoteStoreNode() {
-        return this.getAttributes().keySet().stream().anyMatch(key -> key.startsWith(REMOTE_STORE_NODE_ATTRIBUTE_KEY_PREFIX));
+        return this.getAttributes().keySet().stream().anyMatch(key -> key.equals(REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY))
+            && this.getAttributes().keySet().stream().anyMatch(key -> key.equals(REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY));
     }
 
     /**

server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeAttribute.java

@@ -55,6 +55,11 @@ public class RemoteStoreNodeAttribute {
         REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY
     );
 
+    public static List<String> REMOTE_CLUSTER_PUBLICATION_REPO_NAME_ATTRIBUTES = List.of(
+        REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY,
+        REMOTE_STORE_ROUTING_TABLE_REPOSITORY_NAME_ATTRIBUTE_KEY
+    );
+
     /**
      * Creates a new {@link RemoteStoreNodeAttribute}
      */
@@ -261,6 +266,14 @@ public boolean equalsWithRepoSkip(Object o, List<String> reposToSkip) {
         return this.getRepositoriesMetadata().equalsIgnoreGenerationsWithRepoSkip(that.getRepositoriesMetadata(), reposToSkip);
     }
 
+    public boolean equalsForRepositories(Object otherNode, List<String> repositoryToValidate) {
+        if (this == otherNode) return true;
+        if (otherNode == null || getClass() != otherNode.getClass()) return false;
+
+        RemoteStoreNodeAttribute other = (RemoteStoreNodeAttribute) otherNode;
+        return this.getRepositoriesMetadata().equalsIgnoreGenerationsForRepo(other.repositoriesMetadata, repositoryToValidate);
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

server/src/test/java/org/opensearch/action/support/clustermanager/TransportClusterManagerNodeActionTests.java

@@ -85,6 +85,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.opensearch.index.remote.RemoteMigrationIndexMetadataUpdaterTests.createIndexMetadataWithRemoteStoreSettings;
+import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY;
 import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY;
 import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY;
 import static org.opensearch.node.remotestore.RemoteStoreNodeService.REMOTE_STORE_COMPATIBILITY_MODE_SETTING;
@@ -901,6 +902,7 @@ public void testDontAllowSwitchingCompatibilityModeForClusterWithMultipleVersion
 
     private Map<String, String> getRemoteStoreNodeAttributes() {
         Map<String, String> remoteStoreNodeAttributes = new HashMap<>();
+        remoteStoreNodeAttributes.put(REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, "my-cluster-repo-1");
         remoteStoreNodeAttributes.put(REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, "my-segment-repo-1");
         remoteStoreNodeAttributes.put(REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, "my-translog-repo-1");
         return remoteStoreNodeAttributes;

server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java

@@ -611,6 +611,100 @@ public void testJoinClusterWithRemoteStateNodeJoiningRemoteStateCluster() {
         JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
     }
 
+    public void testJoinRemotePublicationClusterWithNonRemoteNodes() {
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remotePublicationNodeAttributes(),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(new HashMap<>());
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testJoinRemotePublicationCluster() {
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remotePublicationNodeAttributes(),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(remotePublicationNodeAttributes());
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
+    public void testJoinRemotePubClusterWithRemoteStoreNodes() {
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remotePublicationNodeAttributes(),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        Map<String, String> newNodeAttributes = new HashMap<>();
+        newNodeAttributes.putAll(remoteStateNodeAttributes(CLUSTER_STATE_REPO));
+        newNodeAttributes.putAll(remoteRoutingTableAttributes(ROUTING_TABLE_REPO));
+        newNodeAttributes.putAll(remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO));
+
+        DiscoveryNode joiningNode = newDiscoveryNode(newNodeAttributes);
+        Exception e = assertThrows(
+            IllegalStateException.class,
+            () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+        );
+        assertTrue(e.getMessage().equals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"));
+    }
+
+    public void testPreventJoinRemotePublicationClusterWithIncompatibleAttributes() {
+        Map<String, String> existingNodeAttributes = remotePublicationNodeAttributes();
+        Map<String, String> remoteStoreNodeAttributes = remotePublicationNodeAttributes();
+        final DiscoveryNode existingNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            existingNodeAttributes,
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(existingNode).localNodeId(existingNode.getId()).build())
+            .build();
+
+        for (Map.Entry<String, String> nodeAttribute : existingNodeAttributes.entrySet()) {
+            remoteStoreNodeAttributes.put(nodeAttribute.getKey(), null);
+            DiscoveryNode joiningNode = newDiscoveryNode(remoteStoreNodeAttributes);
+            Exception e = assertThrows(
+                IllegalStateException.class,
+                () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
+            );
+            assertTrue(
+                e.getMessage().equals("joining node [" + joiningNode + "] doesn't have the node attribute [" + nodeAttribute.getKey() + "]")
+                    || e.getMessage()
+                        .equals(
+                            "a remote store node ["
+                                + joiningNode
+                                + "] is trying to join a remote store cluster with incompatible node attributes in comparison with existing node ["
+                                + currentState.getNodes().getNodes().values().stream().findFirst().get()
+                                + "]"
+                        )
+            );
+
+            remoteStoreNodeAttributes.put(nodeAttribute.getKey(), nodeAttribute.getValue());
+        }
+    }
+
     public void testPreventJoinClusterWithRemoteStateNodeJoiningRemoteStoreCluster() {
         Map<String, String> existingNodeAttributes = remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO);
         final DiscoveryNode existingNode = new DiscoveryNode(
@@ -628,16 +722,7 @@ public void testPreventJoinClusterWithRemoteStateNodeJoiningRemoteStoreCluster()
             IllegalStateException.class,
             () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
         );
-        assertTrue(
-            e.getMessage()
-                .equals(
-                    "a remote store node ["
-                        + joiningNode
-                        + "] is trying to join a remote store cluster with incompatible node attributes in comparison with existing node ["
-                        + currentState.getNodes().getNodes().values().stream().findFirst().get()
-                        + "]"
-                )
-        );
+        assertTrue(e.getMessage().equals("a non remote store node [" + joiningNode + "] is trying to join a remote store cluster"));
     }
 
     public void testPreventJoinClusterWithRemoteStoreNodeJoiningRemoteStateCluster() {
@@ -657,16 +742,7 @@ public void testPreventJoinClusterWithRemoteStoreNodeJoiningRemoteStateCluster()
             IllegalStateException.class,
             () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
         );
-        assertTrue(
-            e.getMessage()
-                .equals(
-                    "a remote store node ["
-                        + joiningNode
-                        + "] is trying to join a remote store cluster with incompatible node attributes in comparison with existing node ["
-                        + currentState.getNodes().getNodes().values().stream().findFirst().get()
-                        + "]"
-                )
-        );
+        assertTrue(e.getMessage().equals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"));
     }
 
     public void testUpdatesClusterStateWithSingleNodeCluster() throws Exception {
@@ -1077,6 +1153,39 @@ public void testRemoteRoutingTableNodeJoinNodeWithRemoteAndRoutingRepoDifference
         JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
     }
 
+    public void testJoinRemoteStoreClusterWithRemotePublicationNodeInMixedMode() {
+        final DiscoveryNode remoteStoreNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            remoteStoreNodeAttributes(SEGMENT_REPO, TRANSLOG_REPO),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final DiscoveryNode nonRemoteStoreNode = new DiscoveryNode(
+            UUIDs.base64UUID(),
+            buildNewFakeTransportAddress(),
+            new HashMap<>(),
+            DiscoveryNodeRole.BUILT_IN_ROLES,
+            Version.CURRENT
+        );
+
+        final Settings settings = Settings.builder()
+            .put(MIGRATION_DIRECTION_SETTING.getKey(), RemoteStoreNodeService.Direction.REMOTE_STORE)
+            .put(REMOTE_STORE_COMPATIBILITY_MODE_SETTING.getKey(), "mixed")
+            .build();
+        final Settings nodeSettings = Settings.builder().put(REMOTE_STORE_MIGRATION_EXPERIMENTAL, "true").build();
+        FeatureFlags.initializeFeatureFlags(nodeSettings);
+        Metadata metadata = Metadata.builder().persistentSettings(settings).build();
+        ClusterState currentState = ClusterState.builder(ClusterName.DEFAULT)
+            .nodes(DiscoveryNodes.builder().add(remoteStoreNode).add(nonRemoteStoreNode).localNodeId(remoteStoreNode.getId()).build())
+            .metadata(metadata)
+            .build();
+
+        DiscoveryNode joiningNode = newDiscoveryNode(remotePublicationNodeAttributes());
+        JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata());
+    }
+
     private void validateRepositoryMetadata(ClusterState updatedState, DiscoveryNode existingNode, int expectedRepositories)
         throws Exception {
 
@@ -1115,6 +1224,7 @@ private DiscoveryNode newDiscoveryNode(Map<String, String> attributes) {
     }
 
     private static final String SEGMENT_REPO = "segment-repo";
+
     private static final String TRANSLOG_REPO = "translog-repo";
     private static final String CLUSTER_STATE_REPO = "cluster-state-repo";
     private static final String COMMON_REPO = "remote-repo";
@@ -1161,6 +1271,13 @@ private Map<String, String> remoteStoreNodeAttributes(String segmentRepoName, St
         };
     }
 
+    private Map<String, String> remotePublicationNodeAttributes() {
+        Map<String, String> existingNodeAttributes = new HashMap<>();
+        existingNodeAttributes.putAll(remoteStateNodeAttributes(CLUSTER_STATE_REPO));
+        existingNodeAttributes.putAll(remoteRoutingTableAttributes(ROUTING_TABLE_REPO));
+        return existingNodeAttributes;
+    }
+
     private Map<String, String> remoteStateNodeAttributes(String clusterStateRepo) {
         String clusterStateRepositoryTypeAttributeKey = String.format(
             Locale.getDefault(),