#111893 Add Warnings For Missing Index Templates

docs/reference/data-streams/promote-data-stream-api.asciidoc

@@ -18,6 +18,10 @@ available, the data stream in the local cluster can be promoted
 to a regular data stream, which allows these data streams to
 be rolled over in the local cluster.
 
+NOTE: When promoting a data stream, ensure the local cluster has a data stream enabled index template that matches the data stream.
+If this is missing, the data stream will not be able to roll over until a matching index template is created.
+This will affect the lifecycle management of the data stream and interfere with the data stream size and retention.
+
 [source,console]
 ----
 POST /_data_stream/_promote/my-data-stream

docs/reference/snapshot-restore/index.asciidoc

@@ -48,6 +48,9 @@ Snapshots don't contain or back up:
 * Node configuration files
 * <<security-files,Security configuration files>>
 
+NOTE: When restoring a data stream, if the target cluster does not have an index template that matches the data stream, the data stream will not be able to roll over until a matching index template is created.
+This will affect the lifecycle management of the data stream and interfere with the data stream size and retention.
+
 [discrete]
 [[feature-state]]
 === Feature states

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/DataStreamsSnapshotsIT.java

@@ -15,6 +15,7 @@
 import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotRequest;
 import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.elasticsearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequest;
+import org.elasticsearch.action.admin.cluster.snapshots.restore.RestoreSnapshotRequestBuilder;
 import org.elasticsearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.elasticsearch.action.admin.indices.alias.Alias;
 import org.elasticsearch.action.admin.indices.alias.IndicesAliasesRequest;
@@ -45,6 +46,7 @@
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.snapshots.AbstractSnapshotIntegTestCase;
 import org.elasticsearch.snapshots.RestoreInfo;
+import org.elasticsearch.snapshots.SnapshotId;
 import org.elasticsearch.snapshots.SnapshotInProgressException;
 import org.elasticsearch.snapshots.SnapshotInfo;
 import org.elasticsearch.snapshots.SnapshotRestoreException;
@@ -62,7 +64,9 @@
 import java.util.stream.Collectors;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoWarningHeaderOnResponse;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertResponse;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertWarningHeaderOnResponse;
 import static org.hamcrest.Matchers.anEmptyMap;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsInAnyOrder;
@@ -80,6 +84,8 @@ public class DataStreamsSnapshotsIT extends AbstractSnapshotIntegTestCase {
     private static final Map<String, Integer> DOCUMENT_SOURCE = Collections.singletonMap("@timestamp", 123);
     public static final String REPO = "repo";
     public static final String SNAPSHOT = "snap";
+    public static final String TEMPLATE_1_ID = "t1";
+    public static final String TEMPLATE_2_ID = "t2";
     private Client client;
 
     private String dsBackingIndexName;
@@ -103,8 +109,8 @@ public void setup() throws Exception {
         Path location = randomRepoPath();
         createRepository(REPO, "fs", location);
 
-        DataStreamIT.putComposableIndexTemplate("t1", List.of("ds", "other-ds"));
-        DataStreamIT.putComposableIndexTemplate("t2", """
+        DataStreamIT.putComposableIndexTemplate(TEMPLATE_1_ID, List.of("ds", "other-ds"));
+        DataStreamIT.putComposableIndexTemplate(TEMPLATE_2_ID, """
             {
                 "properties": {
                   "@timestamp": {
@@ -1335,4 +1341,149 @@ public void testRestoreDataStreamAliasWithConflictingIndicesAlias() throws Excep
         );
         assertThat(e.getMessage(), containsString("data stream alias and indices alias have the same name (my-alias)"));
     }
+
+    public void testWarningHeaderOnRestoreWithoutTemplates() throws Exception {
+        String datastreamName = "ds";
+
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setIndices(datastreamName)
+            .setIncludeGlobalState(false)
+            .get();
+
+        RestStatus status = createSnapshotResponse.getSnapshotInfo().status();
+        SnapshotId snapshotId = createSnapshotResponse.getSnapshotInfo().snapshotId();
+        assertEquals(RestStatus.OK, status);
+
+        assertEquals(Collections.singletonList(dsBackingIndexName), getSnapshot(REPO, SNAPSHOT).indices());
+
+        assertAcked(
+            client.execute(
+                DeleteDataStreamAction.INSTANCE,
+                new DeleteDataStreamAction.Request(TEST_REQUEST_TIMEOUT, datastreamName, "other-ds")
+            )
+        );
+
+        assertAcked(
+            client.execute(
+                TransportDeleteComposableIndexTemplateAction.TYPE,
+                new TransportDeleteComposableIndexTemplateAction.Request(TEMPLATE_1_ID)
+            ).get()
+        );
+
+        RestoreSnapshotRequestBuilder request = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setIndices(datastreamName);
+
+        assertWarningHeaderOnResponse(
+            client,
+            request,
+            "Snapshot ["
+                + snapshotId
+                + "] contains data stream ["
+                + datastreamName
+                + "] but custer does not have a matching index "
+                + "template. This will cause rollover to fail until a matching index template is created"
+        );
+
+    }
+
+    public void testWarningHeaderAbsentOnRestoreWithTemplates() throws Exception {
+        String datastreamName = "ds";
+
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setIndices(datastreamName)
+            .setIncludeGlobalState(false)
+            .get();
+
+        RestStatus status = createSnapshotResponse.getSnapshotInfo().status();
+        SnapshotId snapshotId = createSnapshotResponse.getSnapshotInfo().snapshotId();
+        assertEquals(RestStatus.OK, status);
+
+        assertEquals(Collections.singletonList(dsBackingIndexName), getSnapshot(REPO, SNAPSHOT).indices());
+
+        assertAcked(
+            client.execute(
+                DeleteDataStreamAction.INSTANCE,
+                new DeleteDataStreamAction.Request(TEST_REQUEST_TIMEOUT, datastreamName, "other-ds", "with-fs")
+            )
+        );
+
+        RestoreSnapshotRequestBuilder request = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setIndices(datastreamName);
+
+        assertNoWarningHeaderOnResponse(
+            client,
+            request,
+            "but custer does not have a matching index template. This will cause rollover to fail until a matching index "
+                + "template is created"
+        );
+
+    }
+
+    /**
+     * This test is muted as it's awaiting the same fix as {@link #testPartialRestoreSnapshotThatIncludesDataStreamWithGlobalState()}
+     */
+    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/107515")
+    public void testWarningHeaderOnRestoreTemplateFromSnapshot() throws Exception {
+        String datastreamName = "ds";
+
+        CreateSnapshotResponse createSnapshotResponse = client.admin()
+            .cluster()
+            .prepareCreateSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setIndices(datastreamName)
+            .setIncludeGlobalState(true)
+            .get();
+
+        RestStatus status = createSnapshotResponse.getSnapshotInfo().status();
+        SnapshotId snapshotId = createSnapshotResponse.getSnapshotInfo().snapshotId();
+        assertEquals(RestStatus.OK, status);
+
+        assertEquals(Collections.singletonList(dsBackingIndexName), getSnapshot(REPO, SNAPSHOT).indices());
+
+        assertAcked(
+            client.execute(
+                DeleteDataStreamAction.INSTANCE,
+                new DeleteDataStreamAction.Request(TEST_REQUEST_TIMEOUT, datastreamName, "other-ds")
+            )
+        );
+
+        assertAcked(
+            client.execute(
+                TransportDeleteComposableIndexTemplateAction.TYPE,
+                new TransportDeleteComposableIndexTemplateAction.Request(TEMPLATE_1_ID)
+            ).get()
+        );
+
+        RestoreSnapshotRequestBuilder request = client.admin()
+            .cluster()
+            .prepareRestoreSnapshot(TEST_REQUEST_TIMEOUT, REPO, SNAPSHOT)
+            .setWaitForCompletion(true)
+            .setRestoreGlobalState(true)
+            .setIndices(datastreamName);
+
+        assertNoWarningHeaderOnResponse(
+            client,
+            request,
+            "Snapshot ["
+                + snapshotId
+                + "] contains data stream ["
+                + datastreamName
+                + "] but custer does not have a matching index "
+                + "template. This will cause rollover to fail until a matching index template is created"
+        );
+
+    }
+
 }

modules/data-streams/src/main/java/org/elasticsearch/datastreams/action/PromoteDataStreamTransportAction.java

@@ -8,6 +8,8 @@
  */
 package org.elasticsearch.datastreams.action;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.elasticsearch.ResourceNotFoundException;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.datastreams.PromoteDataStreamAction;
@@ -23,6 +25,8 @@
 import org.elasticsearch.cluster.metadata.Metadata;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Priority;
+import org.elasticsearch.common.logging.HeaderWarning;
+import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.core.SuppressForbidden;
 import org.elasticsearch.indices.SystemIndices;
@@ -31,8 +35,12 @@
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
+import static org.elasticsearch.core.Strings.format;
+
 public class PromoteDataStreamTransportAction extends AcknowledgedTransportMasterNodeAction<PromoteDataStreamAction.Request> {
 
+    private static final Logger logger = LogManager.getLogger(PromoteDataStreamTransportAction.class);
+
     private final SystemIndices systemIndices;
 
     @Inject
@@ -94,16 +102,41 @@ private void submitUnbatchedTask(@SuppressWarnings("SameParameterValue") String
 
     static ClusterState promoteDataStream(ClusterState currentState, PromoteDataStreamAction.Request request) {
         DataStream dataStream = currentState.getMetadata().dataStreams().get(request.getName());
+
         if (dataStream == null) {
             throw new ResourceNotFoundException("data stream [" + request.getName() + "] does not exist");
         }
 
+        warnIfTemplateMissingForDatastream(dataStream, currentState);
+
         DataStream promotedDataStream = dataStream.promoteDataStream();
         Metadata.Builder metadata = Metadata.builder(currentState.metadata());
         metadata.put(promotedDataStream);
         return ClusterState.builder(currentState).metadata(metadata).build();
     }
 
+    private static void warnIfTemplateMissingForDatastream(DataStream dataStream, ClusterState currentState) {
+        var datastreamName = dataStream.getName();
+
+        var matchingIndex = currentState.metadata()
+            .templatesV2()
+            .values()
+            .stream()
+            .filter(cit -> cit.getDataStreamTemplate() != null)
+            .flatMap(cit -> cit.indexPatterns().stream())
+            .anyMatch(pattern -> Regex.simpleMatch(pattern, datastreamName));
+
+        if (matchingIndex == false) {
+            String warningMessage = format(
+                "Data stream [%s] does not have a matching index template. This will cause rollover to fail until a matching index "
+                    + "template is created",
+                datastreamName
+            );
+            logger.warn(() -> warningMessage);
+            HeaderWarning.addWarning(warningMessage);
+        }
+    }
+
     @Override
     protected ClusterBlockException checkBlock(PromoteDataStreamAction.Request request, ClusterState state) {
         return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_WRITE);

server/src/main/java/org/elasticsearch/snapshots/RestoreService.java

@@ -26,6 +26,7 @@
 import org.elasticsearch.cluster.SnapshotDeletionsInProgress;
 import org.elasticsearch.cluster.block.ClusterBlocks;
 import org.elasticsearch.cluster.metadata.AliasMetadata;
+import org.elasticsearch.cluster.metadata.ComposableIndexTemplate;
 import org.elasticsearch.cluster.metadata.DataStream;
 import org.elasticsearch.cluster.metadata.DataStreamAlias;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
@@ -52,6 +53,7 @@
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
+import org.elasticsearch.common.logging.HeaderWarning;
 import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.regex.Regex;
 import org.elasticsearch.common.settings.ClusterSettings;
@@ -398,6 +400,8 @@ private void startRestore(
         Map<String, DataStream> dataStreamsToRestore = result.v1();
         Map<String, DataStreamAlias> dataStreamAliasesToRestore = result.v2();
 
+        validateDataStreamTemplatesExistAndWarnIfMissing(dataStreamsToRestore, snapshotInfo, globalMetadata);
+
         // Remove the data streams from the list of requested indices
         requestIndices.removeAll(dataStreamsToRestore.keySet());
 
@@ -510,6 +514,35 @@ private void startRestore(
         );
     }
 
+    private void validateDataStreamTemplatesExistAndWarnIfMissing(
+        Map<String, DataStream> dataStreamsToRestore,
+        SnapshotInfo snapshotInfo,
+        Metadata globalMetadata
+    ) {
+
+        Stream<ComposableIndexTemplate> streams = Stream.concat(
+            clusterService.state().metadata().templatesV2().values().stream(),
+            globalMetadata == null ? Stream.empty() : globalMetadata.templatesV2().values().stream()
+        );
+
+        Set<String> templatePatterns = streams.filter(cit -> cit.getDataStreamTemplate() != null)
+            .flatMap(cit -> cit.indexPatterns().stream())
+            .collect(Collectors.toSet());
+
+        for (String name : dataStreamsToRestore.keySet()) {
+            if (templatePatterns.stream().noneMatch(pattern -> Regex.simpleMatch(pattern, name))) {
+                String warningMessage = format(
+                    "Snapshot [%s] contains data stream [%s] but custer does not have a matching index template. This will cause"
+                        + " rollover to fail until a matching index template is created",
+                    snapshotInfo.snapshotId(),
+                    name
+                );
+                logger.warn(() -> warningMessage);
+                HeaderWarning.addWarning(warningMessage);
+            }
+        }
+    }
+
     @SuppressForbidden(reason = "legacy usage of unbatched task") // TODO add support for batching here
     private void submitUnbatchedTask(@SuppressWarnings("SameParameterValue") String source, ClusterStateUpdateTask task) {
         clusterService.submitUnbatchedStateUpdateTask(source, task);