Internal: AsyncShardFetch can hang if there are new nodes in cluster state

The AsyncShardFetch retrieves shard information from the different nodes in order to detirment the best location for unassigned shards. The class uses TransportNodesListGatewayStartedShards and TransportNodesListShardStoreMetaData in order to fetch this information. These actions, inherit from TransportNodesAction and are activated using a list of node ids. Those node ids are extracted from the cluster state that is used to assign shards.

If we perform a reroute and adding new news in the same cluster state update task, it is possible that the AsyncShardFetch administration is based on
a different cluster state then the one used by TransportNodesAction to resolve nodes. This can cause a problem since TransportNodesAction filters away unkown nodes, causing the administration in AsyncShardFetch to get confused.

This commit fixes this allowing to override node resolving in TransportNodesAction and uses the exact node ids transfered by AsyncShardFetch

core/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java

@@ -83,6 +83,11 @@ public abstract class TransportNodesAction<NodesRequest extends BaseNodesRequest
         return nodesIds;
     }
 
+    protected String[] resolveNodes(NodesRequest request, ClusterState clusterState) {
+        return clusterState.nodes().resolveNodesIds(request.nodesIds());
+    }
+
+
     private class AsyncAction {
 
         private final NodesRequest request;
@@ -96,7 +101,7 @@ public abstract class TransportNodesAction<NodesRequest extends BaseNodesRequest
             this.request = request;
             this.listener = listener;
             clusterState = clusterService.state();
-            String[] nodesIds = clusterState.nodes().resolveNodesIds(request.nodesIds());
+            String[] nodesIds = resolveNodes(request, clusterState);
             this.nodesIds = filterNodeIds(clusterState.nodes(), nodesIds);
             this.responses = new AtomicReferenceArray<>(this.nodesIds.length);
         }

core/src/main/java/org/elasticsearch/gateway/AsyncShardFetch.java

@@ -165,19 +165,29 @@ public abstract class AsyncShardFetch<T extends BaseNodeResponse> implements Rel
     protected synchronized void processAsyncFetch(ShardId shardId, T[] responses, FailedNodeException[] failures) {
         if (closed) {
             // we are closed, no need to process this async fetch at all
+            logger.trace("{} ignoring fetched [{}] results, already closed", shardId, type);
             return;
         }
+        logger.trace("{} processing fetched [{}] results", shardId, type);
+
         if (responses != null) {
             for (T response : responses) {
                 NodeEntry<T> nodeEntry = cache.get(response.getNode().getId());
                 // if the entry is there, and not marked as failed already, process it
-                if (nodeEntry != null && nodeEntry.isFailed() == false) {
+                if (nodeEntry == null) {
+                    continue;
+                }
+                if (nodeEntry.isFailed()) {
+                    logger.trace("{} node {} has failed for [{}] (failure [{}])", shardId, nodeEntry.getNodeId(), type, nodeEntry.getFailure());
+                } else {
+                    logger.trace("{} marking {} as done for [{}]", shardId, nodeEntry.getNodeId(), type);
                     nodeEntry.doneFetching(response);
                 }
             }
         }
         if (failures != null) {
             for (FailedNodeException failure : failures) {
+                logger.trace("{} processing failure {} for [{}]", shardId, failure, type);
                 NodeEntry<T> nodeEntry = cache.get(failure.nodeId());
                 // if the entry is there, and not marked as failed already, process it
                 if (nodeEntry != null && nodeEntry.isFailed() == false) {
@@ -253,6 +263,7 @@ public abstract class AsyncShardFetch<T extends BaseNodeResponse> implements Rel
     // visible for testing
     void asyncFetch(final ShardId shardId, final String[] nodesIds, final MetaData metaData) {
         IndexMetaData indexMetaData = metaData.index(shardId.getIndex());
+        logger.trace("{} fetching [{}] from {}", shardId, type, nodesIds);
         action.list(shardId, indexMetaData, nodesIds, new ActionListener<BaseNodesResponse<T>>() {
             @Override
             public void onResponse(BaseNodesResponse<T> response) {

core/src/main/java/org/elasticsearch/gateway/TransportNodesListGatewayStartedShards.java

@@ -27,6 +27,7 @@ import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.nodes.*;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterService;
+import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.inject.Inject;
@@ -68,6 +69,13 @@ public class TransportNodesListGatewayStartedShards extends TransportNodesAction
         execute(new Request(shardId, indexMetaData.getUUID(), nodesIds), listener);
     }
 
+    @Override
+    protected String[] resolveNodes(Request request, ClusterState clusterState) {
+        // default implementation may filter out non existent nodes. it's important to keep exactly the ids
+        // we were given for accounting on the caller
+        return request.nodesIds();
+    }
+
     @Override
     protected boolean transportCompress() {
         return true; // this can become big...

core/src/main/java/org/elasticsearch/indices/store/TransportNodesListShardStoreMetaData.java

@@ -27,6 +27,7 @@ import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.nodes.*;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterService;
+import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.inject.Inject;
@@ -81,6 +82,13 @@ public class TransportNodesListShardStoreMetaData extends TransportNodesAction<T
         execute(new Request(shardId, false, nodesIds), listener);
     }
 
+    @Override
+    protected String[] resolveNodes(Request request, ClusterState clusterState) {
+        // default implementation may filter out non existent nodes. it's important to keep exactly the ids
+        // we were given for accounting on the caller
+        return request.nodesIds();
+    }
+
     @Override
     protected NodeRequest newNodeRequest(String nodeId, Request request) {
         return new NodeRequest(nodeId, request);

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

@@ -31,6 +31,7 @@ import org.elasticsearch.discovery.zen.elect.ElectMasterService;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.test.ElasticsearchIntegrationTest;
 import org.elasticsearch.test.ElasticsearchIntegrationTest.ClusterScope;
+import org.elasticsearch.test.junit.annotations.TestLogging;
 import org.junit.Test;
 
 import java.util.concurrent.ExecutionException;
@@ -46,6 +47,7 @@ import static org.hamcrest.Matchers.*;
 public class MinimumMasterNodesTests extends ElasticsearchIntegrationTest {
 
     @Test
+    @TestLogging("cluster.service:TRACE,discovery.zen:TRACE,gateway:TRACE,transport.tracer:TRACE")
     public void simpleMinimumMasterNodes() throws Exception {
 
         Settings settings = settingsBuilder()

core/src/test/java/org/elasticsearch/indices/state/RareClusterStateTests.java

@@ -20,24 +20,27 @@
 package org.elasticsearch.indices.state;
 
 import com.google.common.collect.ImmutableMap;
-
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingResponse;
 import org.elasticsearch.action.index.IndexResponse;
-import org.elasticsearch.cluster.ClusterInfo;
+import org.elasticsearch.cluster.*;
-import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.block.ClusterBlocks;
-import org.elasticsearch.cluster.DiskUsage;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MappingMetaData;
+import org.elasticsearch.cluster.metadata.MetaData;
+import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.cluster.routing.RoutingNodes;
 import org.elasticsearch.cluster.routing.RoutingTable;
 import org.elasticsearch.cluster.routing.ShardRouting;
+import org.elasticsearch.cluster.routing.allocation.AllocationService;
 import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.transport.DummyTransportAddress;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.discovery.DiscoveryModule;
 import org.elasticsearch.discovery.DiscoverySettings;
@@ -52,19 +55,12 @@ import org.elasticsearch.test.junit.annotations.TestLogging;
 import org.junit.Test;
 
 import java.io.IOException;
-import java.util.Arrays;
+import java.util.*;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
-import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.*;
-import static org.hamcrest.Matchers.hasItem;
-import static org.hamcrest.Matchers.hasSize;
-import static org.hamcrest.Matchers.instanceOf;
 
 /**
  */
@@ -102,6 +98,72 @@ public class RareClusterStateTests extends ElasticsearchIntegrationTest {
         allocator.allocateUnassigned(routingAllocation);
     }
 
+    @Test
+    @TestLogging("gateway:TRACE")
+    public void testAssignmentWithJustAddedNodes() throws Exception {
+        internalCluster().startNode();
+        final String index = "index";
+        prepareCreate(index).setSettings(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1, IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0).get();
+        ensureGreen(index);
+
+        // close to have some unassigned started shards shards..
+        client().admin().indices().prepareClose(index).get();
+
+
+        final String masterName = internalCluster().getMasterName();
+        final ClusterService clusterService = internalCluster().clusterService(masterName);
+        final AllocationService allocationService = internalCluster().getInstance(AllocationService.class, masterName);
+        clusterService.submitStateUpdateTask("test-inject-node-and-reroute", new ClusterStateUpdateTask() {
+            @Override
+            public ClusterState execute(ClusterState currentState) throws Exception {
+                // inject a node
+                ClusterState.Builder builder = ClusterState.builder(currentState);
+                builder.nodes(DiscoveryNodes.builder(currentState.nodes()).put(new DiscoveryNode("_non_existent", DummyTransportAddress.INSTANCE, Version.CURRENT)));
+
+                // open index
+                final IndexMetaData indexMetaData = IndexMetaData.builder(currentState.metaData().index(index)).state(IndexMetaData.State.OPEN).build();
+
+                builder.metaData(MetaData.builder(currentState.metaData()).put(indexMetaData, true));
+                builder.blocks(ClusterBlocks.builder().blocks(currentState.blocks()).removeIndexBlocks(index));
+                ClusterState updatedState = builder.build();
+
+                RoutingTable.Builder routingTable = RoutingTable.builder(updatedState.routingTable());
+                routingTable.addAsRecovery(updatedState.metaData().index(index));
+                updatedState = ClusterState.builder(updatedState).routingTable(routingTable).build();
+
+                RoutingAllocation.Result result = allocationService.reroute(updatedState);
+                return ClusterState.builder(updatedState).routingResult(result).build();
+
+            }
+
+            @Override
+            public void onFailure(String source, Throwable t) {
+
+            }
+        });
+        ensureGreen(index);
+        // remove the extra node
+        clusterService.submitStateUpdateTask("test-remove-injected-node", new ClusterStateUpdateTask() {
+            @Override
+            public ClusterState execute(ClusterState currentState) throws Exception {
+                // inject a node
+                ClusterState.Builder builder = ClusterState.builder(currentState);
+                builder.nodes(DiscoveryNodes.builder(currentState.nodes()).remove("_non_existent"));
+
+                currentState = builder.build();
+                RoutingAllocation.Result result = allocationService.reroute(currentState);
+                return ClusterState.builder(currentState).routingResult(result).build();
+
+            }
+
+            @Override
+            public void onFailure(String source, Throwable t) {
+
+            }
+        });
+    }
+
+
     @Test
     @TestLogging(value = "cluster.service:TRACE")
     public void testDeleteCreateInOneBulk() throws Exception {
@@ -190,6 +252,7 @@ public class RareClusterStateTests extends ElasticsearchIntegrationTest {
             public void onResponse(PutMappingResponse response) {
                 putMappingResponse.set(response);
             }
+
             @Override
             public void onFailure(Throwable e) {
                 putMappingResponse.set(e);
@@ -221,6 +284,7 @@ public class RareClusterStateTests extends ElasticsearchIntegrationTest {
             public void onResponse(IndexResponse response) {
                 docIndexResponse.set(response);
             }
+
             @Override
             public void onFailure(Throwable e) {
                 docIndexResponse.set(e);
@@ -304,6 +368,7 @@ public class RareClusterStateTests extends ElasticsearchIntegrationTest {
             public void onResponse(PutMappingResponse response) {
                 putMappingResponse.set(response);
             }
+
             @Override
             public void onFailure(Throwable e) {
                 putMappingResponse.set(e);
@@ -329,6 +394,7 @@ public class RareClusterStateTests extends ElasticsearchIntegrationTest {
             public void onResponse(IndexResponse response) {
                 docIndexResponse.set(response);
             }
+
             @Override
             public void onFailure(Throwable e) {
                 docIndexResponse.set(e);