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* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
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package org.elasticsearch.action.admin.cluster.allocation;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.master.TransportMasterNodeAction;
import org.elasticsearch.cluster.ClusterInfo;
import org.elasticsearch.cluster.ClusterInfoService;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.block.ClusterBlockException;
import org.elasticsearch.cluster.block.ClusterBlockLevel;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.routing.RoutingNodes;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.MoveDecision;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.cluster.routing.allocation.AllocateUnassignedDecision;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation.DebugMode;
import org.elasticsearch.cluster.routing.allocation.ShardAllocationDecision;
import org.elasticsearch.cluster.routing.allocation.allocator.ShardsAllocator;
import org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.gateway.GatewayAllocator;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;
import java.util.List;
/**
* The {@code TransportClusterAllocationExplainAction} is responsible for actually executing the explanation of a shard's allocation on the
* master node in the cluster.
*/
public class TransportClusterAllocationExplainAction
extends TransportMasterNodeAction<ClusterAllocationExplainRequest, ClusterAllocationExplainResponse> {
private final ClusterInfoService clusterInfoService;
private final AllocationDeciders allocationDeciders;
private final ShardsAllocator shardAllocator;
private final GatewayAllocator gatewayAllocator;
@Inject
public TransportClusterAllocationExplainAction(Settings settings, TransportService transportService, ClusterService clusterService,
ThreadPool threadPool, ActionFilters actionFilters,
IndexNameExpressionResolver indexNameExpressionResolver,
ClusterInfoService clusterInfoService, AllocationDeciders allocationDeciders,
ShardsAllocator shardAllocator, GatewayAllocator gatewayAllocator) {
super(settings, ClusterAllocationExplainAction.NAME, transportService, clusterService, threadPool, actionFilters,
indexNameExpressionResolver, ClusterAllocationExplainRequest::new);
this.clusterInfoService = clusterInfoService;
this.allocationDeciders = allocationDeciders;
this.shardAllocator = shardAllocator;
this.gatewayAllocator = gatewayAllocator;
}
@Override
protected String executor() {
return ThreadPool.Names.MANAGEMENT;
}
@Override
protected ClusterBlockException checkBlock(ClusterAllocationExplainRequest request, ClusterState state) {
return state.blocks().globalBlockedException(ClusterBlockLevel.METADATA_READ);
}
@Override
protected ClusterAllocationExplainResponse newResponse() {
return new ClusterAllocationExplainResponse();
}
@Override
protected void masterOperation(final ClusterAllocationExplainRequest request, final ClusterState state,
final ActionListener<ClusterAllocationExplainResponse> listener) {
final RoutingNodes routingNodes = state.getRoutingNodes();
final ClusterInfo clusterInfo = clusterInfoService.getClusterInfo();
final RoutingAllocation allocation = new RoutingAllocation(allocationDeciders, routingNodes, state,
clusterInfo, System.nanoTime(), false);
ShardRouting shardRouting = findShardToExplain(request, allocation);
logger.debug("explaining the allocation for [{}], found shard [{}]", request, shardRouting);
ClusterAllocationExplanation cae = explainShard(shardRouting, allocation,
request.includeDiskInfo() ? clusterInfo : null, request.includeYesDecisions(), gatewayAllocator, shardAllocator);
listener.onResponse(new ClusterAllocationExplainResponse(cae));
}
// public for testing
public static ClusterAllocationExplanation explainShard(ShardRouting shardRouting, RoutingAllocation allocation,
ClusterInfo clusterInfo, boolean includeYesDecisions,
GatewayAllocator gatewayAllocator, ShardsAllocator shardAllocator) {
allocation.setDebugMode(includeYesDecisions ? DebugMode.ON : DebugMode.EXCLUDE_YES_DECISIONS);
ShardAllocationDecision shardDecision;
if (shardRouting.initializing() || shardRouting.relocating()) {
shardDecision = ShardAllocationDecision.NOT_TAKEN;
} else {
AllocateUnassignedDecision allocateDecision = shardRouting.unassigned() ?
gatewayAllocator.decideUnassignedShardAllocation(shardRouting, allocation) : AllocateUnassignedDecision.NOT_TAKEN;
if (allocateDecision.isDecisionTaken() == false) {
shardDecision = shardAllocator.decideShardAllocation(shardRouting, allocation);
} else {
shardDecision = new ShardAllocationDecision(allocateDecision, MoveDecision.NOT_TAKEN);
}
}
return new ClusterAllocationExplanation(shardRouting,
shardRouting.currentNodeId() != null ? allocation.nodes().get(shardRouting.currentNodeId()) : null,
shardRouting.relocatingNodeId() != null ? allocation.nodes().get(shardRouting.relocatingNodeId()) : null,
clusterInfo, shardDecision);
}
// public for testing
public static ShardRouting findShardToExplain(ClusterAllocationExplainRequest request, RoutingAllocation allocation) {
ShardRouting foundShard = null;
if (request.useAnyUnassignedShard()) {
// If we can use any shard, just pick the first unassigned one (if there are any)
RoutingNodes.UnassignedShards.UnassignedIterator ui = allocation.routingNodes().unassigned().iterator();
if (ui.hasNext()) {
foundShard = ui.next();
}
if (foundShard == null) {
throw new IllegalStateException("unable to find any unassigned shards to explain [" + request + "]");
}
} else {
String index = request.getIndex();
int shard = request.getShard();
if (request.isPrimary()) {
// If we're looking for the primary shard, there's only one copy, so pick it directly
foundShard = allocation.routingTable().shardRoutingTable(index, shard).primaryShard();
if (request.getCurrentNode() != null) {
DiscoveryNode primaryNode = allocation.nodes().resolveNode(request.getCurrentNode());
// the primary is assigned to a node other than the node specified in the request
if (primaryNode.getId().equals(foundShard.currentNodeId()) == false) {
throw new IllegalStateException("unable to find primary shard assigned to node [" + request.getCurrentNode() + "]");
}
}
} else {
// If looking for a replica, go through all the replica shards
List<ShardRouting> replicaShardRoutings = allocation.routingTable().shardRoutingTable(index, shard).replicaShards();
if (request.getCurrentNode() != null) {
// the request is to explain a replica shard already assigned on a particular node,
// so find that shard copy
DiscoveryNode replicaNode = allocation.nodes().resolveNode(request.getCurrentNode());
for (ShardRouting replica : replicaShardRoutings) {
if (replicaNode.getId().equals(replica.currentNodeId())) {
foundShard = replica;
break;
}
}
if (foundShard == null) {
throw new IllegalStateException("unable to find a replica shard assigned to node [" +
request.getCurrentNode() + "]");
}
} else {
if (replicaShardRoutings.size() > 0) {
// Pick the first replica at the very least
foundShard = replicaShardRoutings.get(0);
for (ShardRouting replica : replicaShardRoutings) {
// In case there are multiple replicas where some are assigned and some aren't,
// try to find one that is unassigned at least
if (replica.unassigned()) {
foundShard = replica;
break;
} else if (replica.started() && (foundShard.initializing() || foundShard.relocating())) {
// prefer started shards to initializing or relocating shards because started shards
// can be explained
foundShard = replica;
}
}
}
}
}
}
if (foundShard == null) {
throw new IllegalStateException("unable to find any shards to explain [" + request + "] in the routing table");
}
return foundShard;
}
}