[7.17] Prevent 6.8 indices upgrade to 8.0 (#82689)

server/src/internalClusterTest/java/org/elasticsearch/gateway/GatewayIndexStateIT.java

@@ -626,7 +626,7 @@ public void testHalfDeletedIndexImport() throws Exception {
                     .putCustom(IndexGraveyard.TYPE, IndexGraveyard.builder().addTombstone(metadata.index("test").getIndex()).build())
                     .build()
             );
-            NodeMetadata.FORMAT.writeAndCleanup(new NodeMetadata(nodeId, Version.CURRENT), paths);
+            NodeMetadata.FORMAT.writeAndCleanup(new NodeMetadata(nodeId, Version.CURRENT, Version.CURRENT), paths);
         });
 
         ensureGreen();

server/src/main/java/org/elasticsearch/cluster/metadata/Metadata.java

@@ -211,6 +211,8 @@ public interface NonRestorableCustom extends Custom {}
 
     private SortedMap<String, IndexAbstraction> indicesLookup;
 
+    private final Version oldestIndexVersion;
+
     private Metadata(
         String clusterUUID,
         boolean clusterUUIDCommitted,
@@ -231,7 +233,8 @@ private Metadata(
         String[] visibleOpenIndices,
         String[] allClosedIndices,
         String[] visibleClosedIndices,
-        SortedMap<String, IndexAbstraction> indicesLookup
+        SortedMap<String, IndexAbstraction> indicesLookup,
+        Version oldestIndexVersion
     ) {
         this.clusterUUID = clusterUUID;
         this.clusterUUIDCommitted = clusterUUIDCommitted;
@@ -253,6 +256,7 @@ private Metadata(
         this.allClosedIndices = allClosedIndices;
         this.visibleClosedIndices = visibleClosedIndices;
         this.indicesLookup = indicesLookup;
+        this.oldestIndexVersion = oldestIndexVersion;
     }
 
     public Metadata withIncrementedVersion() {
@@ -276,7 +280,8 @@ public Metadata withIncrementedVersion() {
             visibleOpenIndices,
             allClosedIndices,
             visibleClosedIndices,
-            indicesLookup
+            indicesLookup,
+            oldestIndexVersion
         );
     }
 
@@ -319,6 +324,10 @@ public CoordinationMetadata coordinationMetadata() {
         return this.coordinationMetadata;
     }
 
+    public Version oldestIndexVersion() {
+        return this.oldestIndexVersion;
+    }
+
     public boolean hasAlias(String alias) {
         IndexAbstraction indexAbstraction = getIndicesLookup().get(alias);
         if (indexAbstraction != null) {
@@ -1717,6 +1726,9 @@ public Metadata build(boolean builtIndicesLookupEagerly) {
             final List<String> allClosedIndices = new ArrayList<>();
             final List<String> visibleClosedIndices = new ArrayList<>();
             final Set<String> allAliases = new HashSet<>();
+
+            int oldestIndexVersionId = Version.CURRENT.id;
+
             for (ObjectCursor<IndexMetadata> cursor : indices.values()) {
                 final IndexMetadata indexMetadata = cursor.value;
                 final String name = indexMetadata.getIndex().getName();
@@ -1738,6 +1750,7 @@ public Metadata build(boolean builtIndicesLookupEagerly) {
                     }
                 }
                 indexMetadata.getAliases().keysIt().forEachRemaining(allAliases::add);
+                oldestIndexVersionId = Math.min(oldestIndexVersionId, indexMetadata.getCreationVersion().id);
             }
 
             final ArrayList<String> duplicates = new ArrayList<>();
@@ -1859,7 +1872,8 @@ public Metadata build(boolean builtIndicesLookupEagerly) {
                 visibleOpenIndicesArray,
                 allClosedIndicesArray,
                 visibleClosedIndicesArray,
-                indicesLookup
+                indicesLookup,
+                Version.fromId(oldestIndexVersionId)
             );
         }
 

server/src/main/java/org/elasticsearch/env/NodeEnvironment.java

@@ -267,7 +267,7 @@ public NodeEnvironment(Settings settings, Environment environment) throws IOExce
             sharedDataPath = null;
             locks = null;
             nodeLockId = -1;
-            nodeMetadata = new NodeMetadata(generateNodeId(settings), Version.CURRENT);
+            nodeMetadata = new NodeMetadata(generateNodeId(settings), Version.CURRENT, Version.CURRENT);
             return;
         }
         boolean success = false;
@@ -473,7 +473,9 @@ private static NodeMetadata loadNodeMetadata(Settings settings, Logger logger, N
             final NodeMetadata legacyMetadata = NodeMetadata.FORMAT.loadLatestState(logger, NamedXContentRegistry.EMPTY, paths);
             if (legacyMetadata == null) {
                 assert nodeIds.isEmpty() : nodeIds;
-                metadata = new NodeMetadata(generateNodeId(settings), Version.CURRENT);
+                // If we couldn't find legacy metadata, we set the latest index version to this version. This happens
+                // when we are starting a new node and there are no indices to worry about.
+                metadata = new NodeMetadata(generateNodeId(settings), Version.CURRENT, Version.CURRENT);
             } else {
                 assert nodeIds.equals(Collections.singleton(legacyMetadata.nodeId())) : nodeIds + " doesn't match " + legacyMetadata;
                 metadata = legacyMetadata;

server/src/main/java/org/elasticsearch/env/NodeMetadata.java

@@ -28,32 +28,43 @@ public final class NodeMetadata {
 
     static final String NODE_ID_KEY = "node_id";
     static final String NODE_VERSION_KEY = "node_version";
+    private static final String OLDEST_INDEX_VERSION_KEY = "oldest_index_version";
 
     private final String nodeId;
 
     private final Version nodeVersion;
+    private final Version oldestIndexVersion;
 
-    public NodeMetadata(final String nodeId, final Version nodeVersion) {
+    public NodeMetadata(final String nodeId, final Version nodeVersion, final Version oldestIndexVersion) {
         this.nodeId = Objects.requireNonNull(nodeId);
         this.nodeVersion = Objects.requireNonNull(nodeVersion);
+        this.oldestIndexVersion = Objects.requireNonNull(oldestIndexVersion);
     }
 
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         NodeMetadata that = (NodeMetadata) o;
-        return nodeId.equals(that.nodeId) && nodeVersion.equals(that.nodeVersion);
+        return nodeId.equals(that.nodeId) && nodeVersion.equals(that.nodeVersion) && oldestIndexVersion.equals(that.oldestIndexVersion);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(nodeId, nodeVersion);
+        return Objects.hash(nodeId, nodeVersion, oldestIndexVersion);
     }
 
     @Override
     public String toString() {
-        return "NodeMetadata{" + "nodeId='" + nodeId + '\'' + ", nodeVersion=" + nodeVersion + '}';
+        return "NodeMetadata{"
+            + "nodeId='"
+            + nodeId
+            + '\''
+            + ", nodeVersion="
+            + nodeVersion
+            + ", oldestIndexVersion="
+            + oldestIndexVersion
+            + '}';
     }
 
     public String nodeId() {
@@ -64,10 +75,14 @@ public Version nodeVersion() {
         return nodeVersion;
     }
 
+    public Version oldestIndexVersion() {
+        return oldestIndexVersion;
+    }
+
     public NodeMetadata upgradeToCurrentVersion() {
         if (nodeVersion.equals(Version.V_EMPTY)) {
             assert Version.CURRENT.major <= Version.V_7_0_0.major + 1 : "version is required in the node metadata from v9 onwards";
-            return new NodeMetadata(nodeId, Version.CURRENT);
+            return new NodeMetadata(nodeId, Version.CURRENT, oldestIndexVersion);
         }
 
         if (nodeVersion.before(Version.CURRENT.minimumIndexCompatibilityVersion())) {
@@ -82,12 +97,13 @@ public NodeMetadata upgradeToCurrentVersion() {
             );
         }
 
-        return nodeVersion.equals(Version.CURRENT) ? this : new NodeMetadata(nodeId, Version.CURRENT);
+        return nodeVersion.equals(Version.CURRENT) ? this : new NodeMetadata(nodeId, Version.CURRENT, oldestIndexVersion);
     }
 
     private static class Builder {
         String nodeId;
         Version nodeVersion;
+        Version oldestIndexVersion;
 
         public void setNodeId(String nodeId) {
             this.nodeId = nodeId;
@@ -97,16 +113,26 @@ public void setNodeVersionId(int nodeVersionId) {
             this.nodeVersion = Version.fromId(nodeVersionId);
         }
 
+        public void setOldestIndexVersion(int oldestIndexVersionId) {
+            this.oldestIndexVersion = Version.fromId(oldestIndexVersionId);
+        }
+
         public NodeMetadata build() {
             final Version nodeVersion;
+            final Version oldestIndexVersion;
             if (this.nodeVersion == null) {
                 assert Version.CURRENT.major <= Version.V_7_0_0.major + 1 : "version is required in the node metadata from v9 onwards";
                 nodeVersion = Version.V_EMPTY;
             } else {
                 nodeVersion = this.nodeVersion;
             }
+            if (this.oldestIndexVersion == null) {
+                oldestIndexVersion = Version.V_EMPTY;
+            } else {
+                oldestIndexVersion = this.oldestIndexVersion;
+            }
 
-            return new NodeMetadata(nodeId, nodeVersion);
+            return new NodeMetadata(nodeId, nodeVersion, oldestIndexVersion);
         }
     }
 
@@ -123,6 +149,7 @@ static class NodeMetadataStateFormat extends MetadataStateFormat<NodeMetadata> {
             objectParser = new ObjectParser<>("node_meta_data", ignoreUnknownFields, Builder::new);
             objectParser.declareString(Builder::setNodeId, new ParseField(NODE_ID_KEY));
             objectParser.declareInt(Builder::setNodeVersionId, new ParseField(NODE_VERSION_KEY));
+            objectParser.declareInt(Builder::setOldestIndexVersion, new ParseField(OLDEST_INDEX_VERSION_KEY));
         }
 
         @Override
@@ -136,6 +163,7 @@ protected XContentBuilder newXContentBuilder(XContentType type, OutputStream str
         public void toXContent(XContentBuilder builder, NodeMetadata nodeMetadata) throws IOException {
             builder.field(NODE_ID_KEY, nodeMetadata.nodeId);
             builder.field(NODE_VERSION_KEY, nodeMetadata.nodeVersion.id);
+            builder.field(OLDEST_INDEX_VERSION_KEY, nodeMetadata.oldestIndexVersion.id);
         }
 
         @Override

server/src/main/java/org/elasticsearch/gateway/GatewayMetaState.java

@@ -107,7 +107,7 @@ public void start(
             final Tuple<Manifest, Metadata> manifestClusterStateTuple;
             try {
                 NodeMetadata.FORMAT.writeAndCleanup(
-                    new NodeMetadata(persistedClusterStateService.getNodeId(), Version.CURRENT),
+                    new NodeMetadata(persistedClusterStateService.getNodeId(), Version.CURRENT, Version.V_EMPTY),
                     persistedClusterStateService.getDataPaths()
                 );
                 manifestClusterStateTuple = metaStateService.loadFullState();
@@ -119,6 +119,19 @@ public void start(
                 .metadata(manifestClusterStateTuple.v2())
                 .build();
 
+            try {
+                NodeMetadata.FORMAT.writeAndCleanup(
+                    new NodeMetadata(
+                        persistedClusterStateService.getNodeId(),
+                        Version.CURRENT,
+                        clusterState.metadata().oldestIndexVersion()
+                    ),
+                    persistedClusterStateService.getDataPaths()
+                );
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+
             final IncrementalClusterStateWriter incrementalClusterStateWriter = new IncrementalClusterStateWriter(
                 settings,
                 clusterService.getClusterSettings(),
@@ -182,7 +195,11 @@ public void start(
                     }
                     // write legacy node metadata to prevent accidental downgrades from spawning empty cluster state
                     NodeMetadata.FORMAT.writeAndCleanup(
-                        new NodeMetadata(persistedClusterStateService.getNodeId(), Version.CURRENT),
+                        new NodeMetadata(
+                            persistedClusterStateService.getNodeId(),
+                            Version.CURRENT,
+                            clusterState.metadata().oldestIndexVersion()
+                        ),
                         persistedClusterStateService.getDataPaths()
                     );
                     success = true;
@@ -216,7 +233,11 @@ public void start(
                     metaStateService.deleteAll();
                     // write legacy node metadata to prevent downgrades from spawning empty cluster state
                     NodeMetadata.FORMAT.writeAndCleanup(
-                        new NodeMetadata(persistedClusterStateService.getNodeId(), Version.CURRENT),
+                        new NodeMetadata(
+                            persistedClusterStateService.getNodeId(),
+                            Version.CURRENT,
+                            clusterState.metadata().oldestIndexVersion()
+                        ),
                         persistedClusterStateService.getDataPaths()
                     );
                 } catch (IOException e) {
@@ -541,7 +562,11 @@ public void setCurrentTerm(long currentTerm) {
                     getWriterSafe().writeFullStateAndCommit(currentTerm, lastAcceptedState);
                 } else {
                     writeNextStateFully = true; // in case of failure; this flag is cleared on success
-                    getWriterSafe().writeIncrementalTermUpdateAndCommit(currentTerm, lastAcceptedState.version());
+                    getWriterSafe().writeIncrementalTermUpdateAndCommit(
+                        currentTerm,
+                        lastAcceptedState.version(),
+                        lastAcceptedState.metadata().oldestIndexVersion()
+                    );
                 }
             } catch (IOException e) {
                 throw new ElasticsearchException(e);