When considering the size of shadow replica indices, set size to 0

Otherwise, when trying to calculate the amount of disk usage *after* the
shard has been allocated, it has incorrectly subtracted the shadow
replica size.

Resolves #17460

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

@@ -30,7 +30,10 @@ import org.elasticsearch.action.admin.indices.stats.IndicesStatsRequest;
 import org.elasticsearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.elasticsearch.action.admin.indices.stats.ShardStats;
 import org.elasticsearch.action.admin.indices.stats.TransportIndicesStatsAction;
+import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.block.ClusterBlockException;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.allocation.decider.DiskThresholdDecider;
@@ -330,7 +333,7 @@ public class InternalClusterInfoService extends AbstractComponent implements Clu
                 ShardStats[] stats = indicesStatsResponse.getShards();
                 ImmutableOpenMap.Builder<String, Long> newShardSizes = ImmutableOpenMap.builder();
                 ImmutableOpenMap.Builder<ShardRouting, String> newShardRoutingToDataPath = ImmutableOpenMap.builder();
-                buildShardLevelInfo(logger, stats, newShardSizes, newShardRoutingToDataPath);
+                buildShardLevelInfo(logger, stats, newShardSizes, newShardRoutingToDataPath, clusterService.state());
                 shardSizes = newShardSizes.build();
                 shardRoutingToDataPath = newShardRoutingToDataPath.build();
             }
@@ -379,14 +382,24 @@ public class InternalClusterInfoService extends AbstractComponent implements Clu
     }
 
     static void buildShardLevelInfo(ESLogger logger, ShardStats[] stats, ImmutableOpenMap.Builder<String, Long> newShardSizes,
-            ImmutableOpenMap.Builder<ShardRouting, String> newShardRoutingToDataPath) {
+                                    ImmutableOpenMap.Builder<ShardRouting, String> newShardRoutingToDataPath, ClusterState state) {
+        MetaData meta = state.getMetaData();
         for (ShardStats s : stats) {
+            IndexMetaData indexMeta = meta.index(s.getShardRouting().index());
+            Settings indexSettings = indexMeta == null ? null : indexMeta.getSettings();
             newShardRoutingToDataPath.put(s.getShardRouting(), s.getDataPath());
             long size = s.getStats().getStore().sizeInBytes();
             String sid = ClusterInfo.shardIdentifierFromRouting(s.getShardRouting());
             if (logger.isTraceEnabled()) {
                 logger.trace("shard: {} size: {}", sid, size);
             }
+            if (indexSettings != null && IndexMetaData.isIndexUsingShadowReplicas(indexSettings)) {
+                // Shards on a shared filesystem should be considered of size 0
+                if (logger.isTraceEnabled()) {
+                    logger.trace("shard: {} is using shadow replicas and will be treated as size 0", sid);
+                }
+                size = 0;
+            }
             newShardSizes.put(sid, size);
         }
     }

core/src/test/java/org/elasticsearch/cluster/DiskUsageTests.java

@@ -23,11 +23,16 @@ import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.cluster.node.stats.NodeStats;
 import org.elasticsearch.action.admin.indices.stats.CommonStats;
 import org.elasticsearch.action.admin.indices.stats.ShardStats;
+import org.elasticsearch.cluster.ClusterName;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.ShardRoutingHelper;
 import org.elasticsearch.cluster.routing.UnassignedInfo;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.DummyTransportAddress;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.shard.ShardPath;
@@ -113,7 +118,8 @@ public class DiskUsageTests extends ESTestCase {
         };
         ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
         ImmutableOpenMap.Builder<ShardRouting, String> routingToPath = ImmutableOpenMap.builder();
-        InternalClusterInfoService.buildShardLevelInfo(logger, stats, shardSizes, routingToPath);
+        ClusterState state = ClusterState.builder(new ClusterName("blarg")).version(0).build();
+        InternalClusterInfoService.buildShardLevelInfo(logger, stats, shardSizes, routingToPath, state);
         assertEquals(2, shardSizes.size());
         assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(test_0)));
         assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(test_1)));
@@ -127,6 +133,53 @@ public class DiskUsageTests extends ESTestCase {
         assertEquals(test1Path.getParent().getParent().getParent().toAbsolutePath().toString(), routingToPath.get(test_1));
     }
 
+    public void testFillShardsWithShadowIndices() {
+        final Index index = new Index("non-shadow", "0xcafe0000");
+        ShardRouting s0 = ShardRouting.newUnassigned(index, 0, null, false, new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo"));
+        ShardRoutingHelper.initialize(s0, "node1");
+        ShardRoutingHelper.moveToStarted(s0);
+        Path i0Path = createTempDir().resolve("indices").resolve(index.getUUID()).resolve("0");
+        CommonStats commonStats0 = new CommonStats();
+        commonStats0.store = new StoreStats(100, 1);
+        final Index index2 = new Index("shadow", "0xcafe0001");
+        ShardRouting s1 = ShardRouting.newUnassigned(index2, 0, null, false, new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo"));
+        ShardRoutingHelper.initialize(s1, "node2");
+        ShardRoutingHelper.moveToStarted(s1);
+        Path i1Path = createTempDir().resolve("indices").resolve(index2.getUUID()).resolve("0");
+        CommonStats commonStats1 = new CommonStats();
+        commonStats1.store = new StoreStats(1000, 1);
+        ShardStats[] stats  = new ShardStats[] {
+                new ShardStats(s0, new ShardPath(false, i0Path, i0Path, s0.shardId()), commonStats0 , null),
+                new ShardStats(s1, new ShardPath(false, i1Path, i1Path, s1.shardId()), commonStats1 , null)
+        };
+        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
+        ImmutableOpenMap.Builder<ShardRouting, String> routingToPath = ImmutableOpenMap.builder();
+        ClusterState state = ClusterState.builder(new ClusterName("blarg"))
+                .version(0)
+                .metaData(MetaData.builder()
+                        .put(IndexMetaData.builder("non-shadow")
+                                .settings(Settings.builder()
+                                        .put(IndexMetaData.SETTING_INDEX_UUID, "0xcafe0000")
+                                        .put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT))
+                                .numberOfShards(1)
+                                .numberOfReplicas(0))
+                        .put(IndexMetaData.builder("shadow")
+                                .settings(Settings.builder()
+                                        .put(IndexMetaData.SETTING_INDEX_UUID, "0xcafe0001")
+                                        .put(IndexMetaData.SETTING_SHADOW_REPLICAS, true)
+                                        .put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT))
+                                .numberOfShards(1)
+                                .numberOfReplicas(0)))
+                .build();
+        logger.info("--> calling buildShardLevelInfo with state: {}", state);
+        InternalClusterInfoService.buildShardLevelInfo(logger, stats, shardSizes, routingToPath, state);
+        assertEquals(2, shardSizes.size());
+        assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(s0)));
+        assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(s1)));
+        assertEquals(100L, shardSizes.get(ClusterInfo.shardIdentifierFromRouting(s0)).longValue());
+        assertEquals(0L, shardSizes.get(ClusterInfo.shardIdentifierFromRouting(s1)).longValue());
+    }
+
     public void testFillDiskUsage() {
         ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvaiableUsages = ImmutableOpenMap.builder();
         ImmutableOpenMap.Builder<String, DiskUsage> newMostAvaiableUsages = ImmutableOpenMap.builder();