InternalClusterInfoService should not ignore hidden indices (#62995) (#63049)

Today InternalClusterInfoService ignores hidden indices when
retrieving shard stats of the cluster. This can lead to suboptimal
shard allocation decisions as the size of shards are taken into
account when allocating new shards or rebalancing existing shards.

Author: tlrx

server/src/internalClusterTest/java/org/elasticsearch/cluster/ClusterInfoServiceIT.java

@@ -41,8 +41,10 @@
 import org.elasticsearch.index.shard.IndexShard;
 import org.elasticsearch.index.store.Store;
 import org.elasticsearch.indices.IndicesService;
+import org.elasticsearch.indices.SystemIndexDescriptor;
 import org.elasticsearch.plugins.ActionPlugin;
 import org.elasticsearch.plugins.Plugin;
+import org.elasticsearch.plugins.SystemIndexPlugin;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.InternalTestCluster;
 import org.elasticsearch.test.transport.MockTransportService;
@@ -51,7 +53,9 @@
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -70,7 +74,9 @@
 @ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class ClusterInfoServiceIT extends ESIntegTestCase {
 
-    public static class TestPlugin extends Plugin implements ActionPlugin {
+    private static final String TEST_SYSTEM_INDEX_NAME = ".test-cluster-info-system-index";
+
+    public static class TestPlugin extends Plugin implements ActionPlugin, SystemIndexPlugin {
 
         private final BlockingActionFilter blockingActionFilter;
 
@@ -82,6 +88,12 @@ public TestPlugin() {
         public List<ActionFilter> getActionFilters() {
             return singletonList(blockingActionFilter);
         }
+
+        @Override
+        public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings settings) {
+            return Collections.singletonList(new SystemIndexDescriptor(TEST_SYSTEM_INDEX_NAME,
+                "System index for [" + getTestClass().getName() + ']'));
+        }
     }
 
     public static class BlockingActionFilter extends org.elasticsearch.action.support.ActionFilter.Simple {
@@ -117,13 +129,18 @@ private void setClusterInfoTimeout(String timeValue) {
 
     public void testClusterInfoServiceCollectsInformation() {
         internalCluster().startNodes(2);
-        assertAcked(prepareCreate("test").setSettings(Settings.builder()
-            .put(Store.INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), 0)
-            .put(EnableAllocationDecider.INDEX_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), EnableAllocationDecider.Rebalance.NONE).build()));
+
+        final String indexName = randomBoolean() ? randomAlphaOfLength(5).toLowerCase(Locale.ROOT) : TEST_SYSTEM_INDEX_NAME;
+        assertAcked(prepareCreate(indexName)
+            .setSettings(Settings.builder()
+                .put(Store.INDEX_STORE_STATS_REFRESH_INTERVAL_SETTING.getKey(), 0)
+                .put(EnableAllocationDecider.INDEX_ROUTING_REBALANCE_ENABLE_SETTING.getKey(), EnableAllocationDecider.Rebalance.NONE)
+                .put(IndexMetadata.SETTING_INDEX_HIDDEN, randomBoolean())
+                .build()));
         if (randomBoolean()) {
-            assertAcked(client().admin().indices().prepareClose("test"));
+            assertAcked(client().admin().indices().prepareClose(indexName));
         }
-        ensureGreen("test");
+        ensureGreen(indexName);
         InternalTestCluster internalTestCluster = internalCluster();
         // Get the cluster info service on the master node
         final InternalClusterInfoService infoService = (InternalClusterInfoService) internalTestCluster

server/src/main/java/org/elasticsearch/cluster/InternalClusterInfoService.java

@@ -262,7 +262,7 @@ protected CountDownLatch updateIndicesStats(final ActionListener<IndicesStatsRes
         final IndicesStatsRequest indicesStatsRequest = new IndicesStatsRequest();
         indicesStatsRequest.clear();
         indicesStatsRequest.store(true);
-        indicesStatsRequest.indicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_CLOSED);
+        indicesStatsRequest.indicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_CLOSED_HIDDEN);
 
         client.admin().indices().stats(indicesStatsRequest, new LatchedActionListener<>(listener, latch));
         return latch;
@@ -417,8 +417,8 @@ static void buildShardLevelInfo(Logger logger, ShardStats[] stats, ImmutableOpen
     }
 
     static void fillDiskUsagePerNode(Logger logger, List<NodeStats> nodeStatsArray,
-            ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvaiableUsages,
-            ImmutableOpenMap.Builder<String, DiskUsage> newMostAvaiableUsages) {
+            ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvailableUsages,
+            ImmutableOpenMap.Builder<String, DiskUsage> newMostAvailableUsages) {
         for (NodeStats nodeStats : nodeStatsArray) {
             if (nodeStats.getFs() == null) {
                 logger.warn("Unable to retrieve node FS stats for {}", nodeStats.getNode().getName());
@@ -449,7 +449,7 @@ static void fillDiskUsagePerNode(Logger logger, List<NodeStats> nodeStatsArray,
                                 nodeId, leastAvailablePath.getTotal().getBytes());
                     }
                 } else {
-                    newLeastAvaiableUsages.put(nodeId, new DiskUsage(nodeId, nodeName, leastAvailablePath.getPath(),
+                    newLeastAvailableUsages.put(nodeId, new DiskUsage(nodeId, nodeName, leastAvailablePath.getPath(),
                         leastAvailablePath.getTotal().getBytes(), leastAvailablePath.getAvailable().getBytes()));
                 }
                 if (mostAvailablePath.getTotal().getBytes() < 0) {
@@ -458,7 +458,7 @@ static void fillDiskUsagePerNode(Logger logger, List<NodeStats> nodeStatsArray,
                                 nodeId, mostAvailablePath.getTotal().getBytes());
                     }
                 } else {
-                    newMostAvaiableUsages.put(nodeId, new DiskUsage(nodeId, nodeName, mostAvailablePath.getPath(),
+                    newMostAvailableUsages.put(nodeId, new DiskUsage(nodeId, nodeName, mostAvailablePath.getPath(),
                         mostAvailablePath.getTotal().getBytes(), mostAvailablePath.getAvailable().getBytes()));
                 }