Projects reserved state is moved to ProjectStateRegistry (elastic#132332)

This commit refactors how project reserved state is stored and accessed in Elasticsearch. Instead of storing reserved state metadata directly within each ProjectMetadata object, the commit moves it to a centralized ProjectStateRegistry.

Note: In mixed-version multiproject clusters, this may cause existing reserved state metadata for projects to temporarily disappear until all nodes have been upgraded and restarted.

It also maintains the logic for resetting reserved state metadata during snapshot restore, ensuring that the reserved state will be reread and re-applied to the cluster state.

Author: alexey-ivanov-es

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -357,6 +357,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ESQL_SAMPLE_OPERATOR_STATUS = def(9_127_0_00);
     public static final TransportVersion ALLOCATION_DECISION_NOT_PREFERRED = def(9_145_0_00);
     public static final TransportVersion ESQL_QUALIFIERS_IN_ATTRIBUTES = def(9_146_0_00);
+    public static final TransportVersion PROJECT_RESERVED_STATE_MOVE_TO_REGISTRY = def(9_147_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/delete/TransportDeleteRepositoryAction.java

@@ -19,6 +19,7 @@
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.project.ProjectResolver;
+import org.elasticsearch.cluster.project.ProjectStateRegistry;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.injection.guice.Inject;
@@ -91,7 +92,7 @@ protected void validateForReservedState(DeleteRepositoryRequest request, Cluster
         super.validateForReservedState(request, state);
 
         validateForReservedState(
-            projectResolver.getProjectMetadata(state).reservedStateMetadata().values(),
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values(),
             reservedStateHandlerName().get(),
             modifiedKeys(request),
             request.toString()

server/src/main/java/org/elasticsearch/action/admin/indices/template/delete/TransportDeleteComposableIndexTemplateAction.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.MetadataIndexTemplateService;
 import org.elasticsearch.cluster.project.ProjectResolver;
+import org.elasticsearch.cluster.project.ProjectStateRegistry;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -95,7 +96,7 @@ protected void validateForReservedState(Request request, ClusterState state) {
         super.validateForReservedState(request, state);
 
         validateForReservedState(
-            projectResolver.getProjectMetadata(state).reservedStateMetadata().values(),
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values(),
             reservedStateHandlerName().get(),
             modifiedKeys(request),
             request.toString()

server/src/main/java/org/elasticsearch/action/admin/indices/template/put/TransportPutComponentTemplateAction.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.cluster.metadata.MetadataIndexTemplateService;
 import org.elasticsearch.cluster.metadata.Template;
 import org.elasticsearch.cluster.project.ProjectResolver;
+import org.elasticsearch.cluster.project.ProjectStateRegistry;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.settings.IndexScopedSettings;
 import org.elasticsearch.common.settings.Settings;
@@ -130,7 +131,7 @@ protected void validateForReservedState(PutComponentTemplateAction.Request reque
         super.validateForReservedState(request, state);
 
         validateForReservedState(
-            projectResolver.getProjectMetadata(state).reservedStateMetadata().values(),
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values(),
             reservedStateHandlerName().get(),
             modifiedKeys(request),
             request.toString()

server/src/main/java/org/elasticsearch/action/admin/indices/template/put/TransportPutComposableIndexTemplateAction.java

@@ -28,6 +28,7 @@
 import org.elasticsearch.cluster.metadata.ProjectId;
 import org.elasticsearch.cluster.metadata.ReservedStateMetadata;
 import org.elasticsearch.cluster.project.ProjectResolver;
+import org.elasticsearch.cluster.project.ProjectStateRegistry;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -87,7 +88,10 @@ protected void masterOperation(
     ) {
         ProjectId projectId = projectResolver.getProjectId();
         verifyIfUsingReservedComponentTemplates(request, state.metadata().reservedStateMetadata().values());
-        verifyIfUsingReservedComponentTemplates(request, state.metadata().getProject(projectId).reservedStateMetadata().values());
+        verifyIfUsingReservedComponentTemplates(
+            request,
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values()
+        );
         ComposableIndexTemplate indexTemplate = request.indexTemplate();
         indexTemplateService.putIndexTemplateV2(
             request.cause(),
@@ -138,7 +142,7 @@ protected void validateForReservedState(Request request, ClusterState state) {
         super.validateForReservedState(request, state);
 
         validateForReservedState(
-            projectResolver.getProjectMetadata(state).reservedStateMetadata().values(),
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values(),
             reservedStateHandlerName().get(),
             modifiedKeys(request),
             request.toString()

server/src/main/java/org/elasticsearch/action/ingest/PutPipelineTransportAction.java

@@ -18,6 +18,7 @@
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.project.ProjectResolver;
+import org.elasticsearch.cluster.project.ProjectStateRegistry;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.ingest.IngestService;
 import org.elasticsearch.injection.guice.Inject;
@@ -80,7 +81,7 @@ protected void validateForReservedState(PutPipelineRequest request, ClusterState
         super.validateForReservedState(request, state);
 
         validateForReservedState(
-            projectResolver.getProjectMetadata(state).reservedStateMetadata().values(),
+            ProjectStateRegistry.get(state).reservedStateMetadata(projectResolver.getProjectId()).values(),
             reservedStateHandlerName().get(),
             modifiedKeys(request),
             request.toString()

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

@@ -61,7 +61,6 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
-import java.util.TreeMap;
 import java.util.function.BiConsumer;
 import java.util.function.BiPredicate;
 import java.util.function.Consumer;
@@ -799,12 +798,6 @@ private Iterator<? extends ToXContent> toXContentChunkedWithSingleProjectFormat(
         @FixForMultiProject
         final ProjectMetadata project = projectMetadata.values().iterator().next();
 
-        // need to combine reserved state together into a single block so we don't get duplicate keys
-        // and not include it in the project xcontent output (through the lack of multi-project params)
-        // use a tree map so the order is deterministic
-        final Map<String, ReservedStateMetadata> clusterReservedState = new TreeMap<>(reservedStateMetadata);
-        clusterReservedState.putAll(project.reservedStateMetadata());
-
         // Similarly, combine cluster and project persistent tasks and report them under a single key
         Iterator<ToXContent> customs = Iterators.flatMap(customs().entrySet().iterator(), entry -> {
             if (entry.getValue().context().contains(context) && ClusterPersistentTasksCustomMetadata.TYPE.equals(entry.getKey()) == false) {
@@ -824,13 +817,20 @@ private Iterator<? extends ToXContent> toXContentChunkedWithSingleProjectFormat(
             );
         }
 
+        // make order deterministic
+        Iterator<ReservedStateMetadata> reservedStateMetadataIterator = reservedStateMetadata.entrySet()
+            .stream()
+            .sorted(Map.Entry.comparingByKey())
+            .map(Map.Entry::getValue)
+            .iterator();
+
         return Iterators.concat(
             start,
             clusterCoordination,
             persistentSettings,
             project.toXContentChunked(p),
             customs,
-            ChunkedToXContentHelper.object("reserved_state", clusterReservedState.values().iterator()),
+            ChunkedToXContentHelper.object("reserved_state", reservedStateMetadataIterator),
             ChunkedToXContentHelper.endObject()
         );
     }
@@ -845,6 +845,7 @@ private static class MetadataDiff implements Diff<Metadata> {
         private final Settings persistentSettings;
         private final Diff<DiffableStringMap> hashesOfConsistentSettings;
         private final ProjectMetadata.ProjectMetadataDiff singleProject;
+
         private final MapDiff<ProjectId, ProjectMetadata, Map<ProjectId, ProjectMetadata>> multiProject;
         private final MapDiff<String, ClusterCustom, ImmutableOpenMap<String, ClusterCustom>> clusterCustoms;
         private final MapDiff<String, ReservedStateMetadata, ImmutableOpenMap<String, ReservedStateMetadata>> reservedStateMetadata;
@@ -981,7 +982,7 @@ private MetadataDiff(StreamInput in) throws IOException {
                     RESERVED_DIFF_VALUE_READER
                 );
 
-                singleProject = new ProjectMetadata.ProjectMetadataDiff(indices, templates, projectCustoms, DiffableUtils.emptyDiff());
+                singleProject = new ProjectMetadata.ProjectMetadataDiff(indices, templates, projectCustoms);
                 multiProject = null;
             } else {
                 fromNodeBeforeMultiProjectsSupport = false;
@@ -1048,7 +1049,7 @@ public void writeTo(StreamOutput out) throws IOException {
                 singleProject.indices().writeTo(out);
                 singleProject.templates().writeTo(out);
                 buildUnifiedCustomDiff().writeTo(out);
-                buildUnifiedReservedStateMetadataDiff().writeTo(out);
+                reservedStateMetadata.writeTo(out);
             } else {
                 clusterCustoms.writeTo(out);
                 reservedStateMetadata.writeTo(out);
@@ -1094,15 +1095,6 @@ public void writeTo(StreamOutput out) throws IOException {
             }
         }
 
-        private Diff<Map<String, ReservedStateMetadata>> buildUnifiedReservedStateMetadataDiff() {
-            return DiffableUtils.merge(
-                reservedStateMetadata,
-                singleProject.reservedStateMetadata(),
-                DiffableUtils.getStringKeySerializer(),
-                RESERVED_DIFF_VALUE_READER
-            );
-        }
-
         @Override
         public Metadata apply(Metadata part) {
             if (empty) {
@@ -1304,12 +1296,7 @@ public void writeTo(StreamOutput out) throws IOException {
             );
             VersionedNamedWriteable.writeVersionedWriteables(out, combinedCustoms);
 
-            List<ReservedStateMetadata> combinedMetadata = new ArrayList<>(
-                reservedStateMetadata.size() + singleProject.reservedStateMetadata().size()
-            );
-            combinedMetadata.addAll(reservedStateMetadata.values());
-            combinedMetadata.addAll(singleProject.reservedStateMetadata().values());
-            out.writeCollection(combinedMetadata);
+            out.writeCollection(reservedStateMetadata.values());
         } else {
             VersionedNamedWriteable.writeVersionedWriteables(out, customs.values());