Make the health node a cluster-scoped persistent task (MP-1969)

Now that the persistent task framework supports cluster-scoped
persistent tasks, we can make the health node persistent task run with
cluster scope.

Author: nielsbauman

server/src/main/java/org/elasticsearch/health/node/selection/HealthNode.java

@@ -13,6 +13,7 @@
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.persistent.AllocatedPersistentTask;
+import org.elasticsearch.persistent.ClusterPersistentTasksCustomMetadata;
 import org.elasticsearch.persistent.PersistentTasksCustomMetadata;
 import org.elasticsearch.tasks.TaskId;
 
@@ -36,8 +37,7 @@ protected void onCancelled() {
 
     @Nullable
     public static PersistentTasksCustomMetadata.PersistentTask<?> findTask(ClusterState clusterState) {
-        PersistentTasksCustomMetadata taskMetadata = clusterState.getMetadata().getProject().custom(PersistentTasksCustomMetadata.TYPE);
-        return taskMetadata == null ? null : taskMetadata.getTask(TASK_NAME);
+        return ClusterPersistentTasksCustomMetadata.getTaskWithId(clusterState, TASK_NAME);
     }
 
     @Nullable

server/src/main/java/org/elasticsearch/health/node/selection/HealthNodeTaskExecutor.java

@@ -73,6 +73,11 @@ private HealthNodeTaskExecutor(ClusterService clusterService, PersistentTasksSer
         this.enabled = ENABLED_SETTING.get(settings);
     }
 
+    @Override
+    public Scope scope() {
+        return Scope.CLUSTER;
+    }
+
     public static HealthNodeTaskExecutor create(
         ClusterService clusterService,
         PersistentTasksService persistentTasksService,

server/src/test/java/org/elasticsearch/cluster/metadata/MetadataTests.java

@@ -38,11 +38,12 @@
 import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.ChunkedToXContent;
 import org.elasticsearch.common.xcontent.XContentHelper;
-import org.elasticsearch.core.FixForMultiProject;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.Predicates;
 import org.elasticsearch.core.SuppressForbidden;
+import org.elasticsearch.health.node.selection.HealthNode;
 import org.elasticsearch.health.node.selection.HealthNodeTaskExecutor;
+import org.elasticsearch.health.node.selection.HealthNodeTaskParams;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexMode;
 import org.elasticsearch.index.IndexNotFoundException;
@@ -843,17 +844,20 @@ public void testParseXContentFormatBeforeMultiProject() throws IOException {
             assertThat(metatdata, notNullValue());
             assertThat(metatdata.clusterUUID(), is("aba1aa1ababbbaabaabaab"));
             assertThat(metatdata.customs().keySet(), containsInAnyOrder("desired_nodes", "cluster_persistent_tasks"));
-            @FixForMultiProject(description = "adjust the assertion once health-node becomes cluster-scoped")
             final var clusterTasks = ClusterPersistentTasksCustomMetadata.get(metatdata);
-            assertThat(clusterTasks.tasks(), hasSize(0));
+            assertThat(clusterTasks.tasks(), hasSize(1));
+            assertThat(
+                clusterTasks.tasks().stream().map(PersistentTasksCustomMetadata.PersistentTask::getTaskName).toList(),
+                containsInAnyOrder("health-node")
+            );
             assertThat(
                 metatdata.getProject().customs().keySet(),
                 containsInAnyOrder("persistent_tasks", "index-graveyard", "component_template")
             );
             final var projectTasks = PersistentTasksCustomMetadata.get(metatdata.getProject());
             assertThat(
                 projectTasks.tasks().stream().map(PersistentTasksCustomMetadata.PersistentTask::getTaskName).toList(),
-                containsInAnyOrder("health-node", "upgrade-system-indices")
+                containsInAnyOrder("upgrade-system-indices")
             );
             assertThat(clusterTasks.getLastAllocationId(), equalTo(projectTasks.getLastAllocationId()));
         }
@@ -2607,8 +2611,24 @@ public void testMultiProjectXContent() throws IOException {
             )
             .toList();
 
-        @FixForMultiProject(description = "considering adding health-node into metadata customs once health-node becomes a cluster task")
-        final Metadata originalMeta = randomMetadata(projects);
+        final Metadata originalMeta = Metadata.builder(randomMetadata(projects))
+            .putCustom(
+                ClusterPersistentTasksCustomMetadata.TYPE,
+                new ClusterPersistentTasksCustomMetadata(
+                    lastAllocationId + 1,
+                    Map.of(
+                        HealthNode.TASK_NAME,
+                        new PersistentTasksCustomMetadata.PersistentTask<>(
+                            HealthNode.TASK_NAME,
+                            HealthNode.TASK_NAME,
+                            HealthNodeTaskParams.INSTANCE,
+                            lastAllocationId + 1,
+                            PersistentTasks.INITIAL_ASSIGNMENT
+                        )
+                    )
+                )
+            )
+            .build();
 
         ToXContent.Params p = new ToXContent.MapParams(
             Map.of("multi-project", "true", Metadata.CONTEXT_MODE_PARAM, Metadata.CONTEXT_MODE_GATEWAY)
@@ -2618,6 +2638,7 @@ public void testMultiProjectXContent() throws IOException {
         final List<NamedXContentRegistry.Entry> registry = new ArrayList<>();
         registry.addAll(ClusterModule.getNamedXWriteables());
         registry.addAll(SystemIndexMigrationExecutor.getNamedXContentParsers());
+        registry.addAll(HealthNodeTaskExecutor.getNamedXContentParsers());
         final var config = XContentParserConfiguration.EMPTY.withRegistry(new NamedXContentRegistry(registry));
 
         try (XContentParser parser = createParser(config, JsonXContent.jsonXContent, bytes)) {
@@ -2628,6 +2649,9 @@ public void testMultiProjectXContent() throws IOException {
                 assertThat(projectTasks.getLastAllocationId(), equalTo(lastAllocationId));
                 assertThat(projectTasks.taskMap().keySet(), equalTo(Set.of(SystemIndexMigrationTaskParams.SYSTEM_INDEX_UPGRADE_TASK_NAME)));
             }
+            final var clusterTasks = ClusterPersistentTasksCustomMetadata.get(fromXContentMeta);
+            assertThat(clusterTasks.getLastAllocationId(), equalTo(lastAllocationId + 1));
+            assertThat(clusterTasks.taskMap().keySet(), equalTo(Set.of(HealthNode.TASK_NAME)));
         }
     }
 

server/src/test/java/org/elasticsearch/health/node/selection/HealthNodeTaskExecutorTests.java

@@ -22,8 +22,8 @@
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.features.FeatureService;
+import org.elasticsearch.persistent.ClusterPersistentTasksCustomMetadata;
 import org.elasticsearch.persistent.PersistentTaskState;
-import org.elasticsearch.persistent.PersistentTasksCustomMetadata;
 import org.elasticsearch.persistent.PersistentTasksService;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.threadpool.TestThreadPool;
@@ -198,10 +198,11 @@ private ClusterState stateWithNodeShuttingDown(ClusterState clusterState, Single
 
     private ClusterState stateWithHealthNodeSelectorTask(ClusterState clusterState) {
         ClusterState.Builder builder = ClusterState.builder(clusterState);
-        PersistentTasksCustomMetadata.Builder tasks = PersistentTasksCustomMetadata.builder();
+        ClusterPersistentTasksCustomMetadata.Builder tasks = ClusterPersistentTasksCustomMetadata.builder();
         tasks.addTask(HealthNode.TASK_NAME, HealthNode.TASK_NAME, new HealthNodeTaskParams(), NO_NODE_FOUND);
 
-        Metadata.Builder metadata = Metadata.builder(clusterState.metadata()).putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build());
+        Metadata.Builder metadata = Metadata.builder(clusterState.metadata())
+            .putCustom(ClusterPersistentTasksCustomMetadata.TYPE, tasks.build());
         return builder.metadata(metadata).build();
     }
 }

server/src/test/java/org/elasticsearch/health/node/selection/HealthNodeTests.java

@@ -14,7 +14,7 @@
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.cluster.node.DiscoveryNodeUtils;
-import org.elasticsearch.persistent.PersistentTasksCustomMetadata;
+import org.elasticsearch.persistent.ClusterPersistentTasksCustomMetadata;
 import org.elasticsearch.test.ESTestCase;
 
 import java.util.Set;
@@ -55,10 +55,10 @@ public void testFindHealthNodeNoTask() {
     }
 
     public void testfindHealthNodeNoAssignment() {
-        PersistentTasksCustomMetadata.Builder tasks = PersistentTasksCustomMetadata.builder();
+        ClusterPersistentTasksCustomMetadata.Builder tasks = ClusterPersistentTasksCustomMetadata.builder();
         tasks.addTask(HealthNode.TASK_NAME, HealthNode.TASK_NAME, HealthNodeTaskParams.INSTANCE, NO_NODE_FOUND);
         ClusterState state = ClusterStateCreationUtils.state(node1, node1, allNodes)
-            .copyAndUpdateMetadata(b -> b.putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build()));
+            .copyAndUpdateMetadata(b -> b.putCustom(ClusterPersistentTasksCustomMetadata.TYPE, tasks.build()));
         assertThat(HealthNode.findHealthNode(state), nullValue());
     }
 

test/framework/src/main/java/org/elasticsearch/action/support/replication/ClusterStateCreationUtils.java

@@ -37,6 +37,7 @@
 import org.elasticsearch.index.shard.IndexLongFieldRange;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.indices.SystemIndices;
+import org.elasticsearch.persistent.ClusterPersistentTasksCustomMetadata;
 import org.elasticsearch.persistent.PersistentTasksCustomMetadata;
 
 import java.util.ArrayList;
@@ -802,12 +803,12 @@ private static String selectAndRemove(Set<String> strings) {
     }
 
     private static Metadata.Builder addHealthNode(Metadata.Builder metadataBuilder, DiscoveryNode healthNode) {
-        PersistentTasksCustomMetadata.Builder tasks = PersistentTasksCustomMetadata.builder();
+        ClusterPersistentTasksCustomMetadata.Builder tasks = ClusterPersistentTasksCustomMetadata.builder();
         PersistentTasksCustomMetadata.Assignment assignment = new PersistentTasksCustomMetadata.Assignment(
             healthNode.getId(),
             randomAlphaOfLength(10)
         );
         tasks.addTask(HealthNode.TASK_NAME, HealthNode.TASK_NAME, HealthNodeTaskParams.INSTANCE, assignment);
-        return metadataBuilder.putCustom(PersistentTasksCustomMetadata.TYPE, tasks.build());
+        return metadataBuilder.putCustom(ClusterPersistentTasksCustomMetadata.TYPE, tasks.build());
     }
 }