org.elasticsearch.cluster.routing.allocation.ShardsAllocation Maven / Gradle / Ivy
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/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.
*/
package org.elasticsearch.cluster.routing.allocation;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.routing.*;
import org.elasticsearch.common.component.AbstractComponent;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.ImmutableSettings;
import org.elasticsearch.common.settings.Settings;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import static org.elasticsearch.cluster.routing.ShardRoutingState.*;
import static org.elasticsearch.common.collect.Sets.*;
/**
* @author kimchy (shay.banon)
*/
public class ShardsAllocation extends AbstractComponent {
private final NodeAllocations nodeAllocations;
public ShardsAllocation() {
this(ImmutableSettings.Builder.EMPTY_SETTINGS);
}
public ShardsAllocation(Settings settings) {
this(settings, new NodeAllocations(settings));
}
@Inject public ShardsAllocation(Settings settings, NodeAllocations nodeAllocations) {
super(settings);
this.nodeAllocations = nodeAllocations;
}
/**
* Applies the started shards. Note, shards can be called several times within this method.
*
* If the same instance of the routing table is returned, then no change has been made.
*/
public RoutingAllocation.Result applyStartedShards(ClusterState clusterState, List startedShards) {
RoutingNodes routingNodes = clusterState.routingNodes();
StartedRerouteAllocation allocation = new StartedRerouteAllocation(routingNodes, clusterState.nodes(), startedShards);
nodeAllocations.applyStartedShards(nodeAllocations, allocation);
boolean changed = applyStartedShards(routingNodes, startedShards);
if (!changed) {
return new RoutingAllocation.Result(false, clusterState.routingTable(), allocation.explanation());
}
reroute(allocation);
return new RoutingAllocation.Result(true, new RoutingTable.Builder().updateNodes(routingNodes).build().validateRaiseException(clusterState.metaData()), allocation.explanation());
}
/**
* Applies the failed shards. Note, shards can be called several times within this method.
*
*
If the same instance of the routing table is returned, then no change has been made.
*/
public RoutingAllocation.Result applyFailedShards(ClusterState clusterState, List failedShards) {
RoutingNodes routingNodes = clusterState.routingNodes();
FailedRerouteAllocation allocation = new FailedRerouteAllocation(routingNodes, clusterState.nodes(), failedShards);
nodeAllocations.applyFailedShards(nodeAllocations, allocation);
boolean changed = applyFailedShards(allocation);
if (!changed) {
return new RoutingAllocation.Result(false, clusterState.routingTable(), allocation.explanation());
}
// If we reroute again, the failed shard will try and be assigned to the same node, which we do no do in the applyFailedShards
// reroute(routingNodes, clusterState.nodes());
return new RoutingAllocation.Result(true, new RoutingTable.Builder().updateNodes(routingNodes).build().validateRaiseException(clusterState.metaData()), allocation.explanation());
}
/**
* Reroutes the routing table based on the live nodes.
*
*
If the same instance of the routing table is returned, then no change has been made.
*/
public RoutingAllocation.Result reroute(ClusterState clusterState) {
RoutingNodes routingNodes = clusterState.routingNodes();
RoutingAllocation allocation = new RoutingAllocation(routingNodes, clusterState.nodes());
if (!reroute(allocation)) {
return new RoutingAllocation.Result(false, clusterState.routingTable(), allocation.explanation());
}
return new RoutingAllocation.Result(true, new RoutingTable.Builder().updateNodes(routingNodes).build().validateRaiseException(clusterState.metaData()), allocation.explanation());
}
private boolean reroute(RoutingAllocation allocation) {
Iterable dataNodes = allocation.nodes().dataNodes().values();
boolean changed = false;
// first, clear from the shards any node id they used to belong to that is now dead
changed |= deassociateDeadNodes(allocation.routingNodes(), dataNodes);
// create a sorted list of from nodes with least number of shards to the maximum ones
applyNewNodes(allocation.routingNodes(), dataNodes);
// elect primaries *before* allocating unassigned, so backups of primaries that failed
// will be moved to primary state and not wait for primaries to be allocated and recovered (*from gateway*)
changed |= electPrimaries(allocation.routingNodes());
// now allocate all the unassigned to available nodes
if (allocation.routingNodes().hasUnassigned()) {
changed |= nodeAllocations.allocateUnassigned(nodeAllocations, allocation);
changed |= allocateUnassigned(allocation);
// elect primaries again, in case this is needed with unassigned allocation
changed |= electPrimaries(allocation.routingNodes());
}
// rebalance
changed |= rebalance(allocation);
return changed;
}
private boolean rebalance(RoutingAllocation allocation) {
boolean changed = false;
List sortedNodesLeastToHigh = allocation.routingNodes().sortedNodesLeastToHigh();
if (sortedNodesLeastToHigh.isEmpty()) {
return false;
}
int lowIndex = 0;
int highIndex = sortedNodesLeastToHigh.size() - 1;
boolean relocationPerformed;
do {
relocationPerformed = false;
while (lowIndex != highIndex) {
RoutingNode lowRoutingNode = sortedNodesLeastToHigh.get(lowIndex);
RoutingNode highRoutingNode = sortedNodesLeastToHigh.get(highIndex);
int averageNumOfShards = allocation.routingNodes().requiredAverageNumberOfShardsPerNode();
// only active shards can be removed so must count only active ones.
if (highRoutingNode.numberOfOwningShards() <= averageNumOfShards) {
highIndex--;
continue;
}
if (lowRoutingNode.shards().size() >= averageNumOfShards) {
lowIndex++;
continue;
}
boolean relocated = false;
List startedShards = highRoutingNode.shardsWithState(STARTED);
for (MutableShardRouting startedShard : startedShards) {
if (!nodeAllocations.canRebalance(startedShard, allocation)) {
continue;
}
if (nodeAllocations.canAllocate(startedShard, lowRoutingNode, allocation).allocate()) {
changed = true;
lowRoutingNode.add(new MutableShardRouting(startedShard.index(), startedShard.id(),
lowRoutingNode.nodeId(), startedShard.currentNodeId(),
startedShard.primary(), INITIALIZING));
startedShard.relocate(lowRoutingNode.nodeId());
relocated = true;
relocationPerformed = true;
break;
}
}
if (!relocated) {
highIndex--;
}
}
} while (relocationPerformed);
return changed;
}
private boolean electPrimaries(RoutingNodes routingNodes) {
boolean changed = false;
for (MutableShardRouting shardEntry : routingNodes.unassigned()) {
if (shardEntry.primary() && !shardEntry.assignedToNode()) {
boolean elected = false;
// primary and not assigned, go over and find a replica that is assigned and active (since it might be relocating)
for (RoutingNode routingNode : routingNodes.nodesToShards().values()) {
for (MutableShardRouting shardEntry2 : routingNode.shards()) {
if (shardEntry.shardId().equals(shardEntry2.shardId()) && shardEntry2.active()) {
assert shardEntry2.assignedToNode();
assert !shardEntry2.primary();
changed = true;
shardEntry.moveFromPrimary();
shardEntry2.moveToPrimary();
elected = true;
break;
}
}
if (elected) {
break;
}
}
}
}
return changed;
}
private boolean allocateUnassigned(RoutingAllocation allocation) {
boolean changed = false;
RoutingNodes routingNodes = allocation.routingNodes();
List nodes = routingNodes.sortedNodesLeastToHigh();
Iterator unassignedIterator = routingNodes.unassigned().iterator();
int lastNode = 0;
while (unassignedIterator.hasNext()) {
MutableShardRouting shard = unassignedIterator.next();
// do the allocation, finding the least "busy" node
for (int i = 0; i < nodes.size(); i++) {
RoutingNode node = nodes.get(lastNode);
lastNode++;
if (lastNode == nodes.size()) {
lastNode = 0;
}
if (nodeAllocations.canAllocate(shard, node, allocation).allocate()) {
int numberOfShardsToAllocate = routingNodes.requiredAverageNumberOfShardsPerNode() - node.shards().size();
if (numberOfShardsToAllocate <= 0) {
continue;
}
changed = true;
node.add(shard);
unassignedIterator.remove();
break;
}
}
}
// allocate all the unassigned shards above the average per node.
for (Iterator it = routingNodes.unassigned().iterator(); it.hasNext();) {
MutableShardRouting shard = it.next();
// go over the nodes and try and allocate the remaining ones
for (RoutingNode routingNode : routingNodes.sortedNodesLeastToHigh()) {
if (nodeAllocations.canAllocate(shard, routingNode, allocation).allocate()) {
changed = true;
routingNode.add(shard);
it.remove();
break;
}
}
}
return changed;
}
/**
* Applies the new nodes to the routing nodes and returns them (just the
* new nodes);
*
* @param liveNodes currently live nodes.
*/
private void applyNewNodes(RoutingNodes routingNodes, Iterable liveNodes) {
for (DiscoveryNode node : liveNodes) {
if (!routingNodes.nodesToShards().containsKey(node.id())) {
RoutingNode routingNode = new RoutingNode(node.id());
routingNodes.nodesToShards().put(node.id(), routingNode);
}
}
}
private boolean deassociateDeadNodes(RoutingNodes routingNodes, Iterable liveNodes) {
boolean changed = false;
Set liveNodeIds = newHashSet();
for (DiscoveryNode liveNode : liveNodes) {
liveNodeIds.add(liveNode.id());
}
Set nodeIdsToRemove = newHashSet();
for (RoutingNode routingNode : routingNodes) {
for (Iterator shardsIterator = routingNode.shards().iterator(); shardsIterator.hasNext();) {
MutableShardRouting shardRoutingEntry = shardsIterator.next();
if (shardRoutingEntry.assignedToNode()) {
// we store the relocation state here since when we call de-assign node
// later on, we will loose this state
boolean relocating = shardRoutingEntry.relocating();
String relocatingNodeId = shardRoutingEntry.relocatingNodeId();
// is this the destination shard that we are relocating an existing shard to?
// we know this since it has a relocating node id (the node we relocate from) and our state is INITIALIZING (and not RELOCATING)
boolean isRelocationDestinationShard = relocatingNodeId != null && shardRoutingEntry.initializing();
boolean currentNodeIsDead = false;
if (!liveNodeIds.contains(shardRoutingEntry.currentNodeId())) {
changed = true;
nodeIdsToRemove.add(shardRoutingEntry.currentNodeId());
if (!isRelocationDestinationShard) {
routingNodes.unassigned().add(shardRoutingEntry);
}
shardRoutingEntry.deassignNode();
currentNodeIsDead = true;
shardsIterator.remove();
}
// move source shard back to active state and cancel relocation mode.
if (relocating && !liveNodeIds.contains(relocatingNodeId)) {
nodeIdsToRemove.add(relocatingNodeId);
if (!currentNodeIsDead) {
changed = true;
shardRoutingEntry.cancelRelocation();
}
}
if (isRelocationDestinationShard && !liveNodeIds.contains(relocatingNodeId)) {
changed = true;
shardsIterator.remove();
}
}
}
}
for (String nodeIdToRemove : nodeIdsToRemove) {
routingNodes.nodesToShards().remove(nodeIdToRemove);
}
return changed;
}
private boolean applyStartedShards(RoutingNodes routingNodes, Iterable startedShardEntries) {
boolean dirty = false;
// apply shards might be called several times with the same shard, ignore it
for (ShardRouting startedShard : startedShardEntries) {
assert startedShard.state() == INITIALIZING;
// retrieve the relocating node id before calling moveToStarted().
String relocatingNodeId = null;
RoutingNode currentRoutingNode = routingNodes.nodesToShards().get(startedShard.currentNodeId());
if (currentRoutingNode != null) {
for (MutableShardRouting shard : currentRoutingNode) {
if (shard.shardId().equals(startedShard.shardId())) {
relocatingNodeId = shard.relocatingNodeId();
if (!shard.started()) {
dirty = true;
shard.moveToStarted();
}
break;
}
}
}
// startedShard is the current state of the shard (post relocation for example)
// this means that after relocation, the state will be started and the currentNodeId will be
// the node we relocated to
if (relocatingNodeId == null)
continue;
RoutingNode sourceRoutingNode = routingNodes.nodesToShards().get(relocatingNodeId);
if (sourceRoutingNode != null) {
Iterator shardsIter = sourceRoutingNode.iterator();
while (shardsIter.hasNext()) {
MutableShardRouting shard = shardsIter.next();
if (shard.shardId().equals(startedShard.shardId())) {
if (shard.relocating()) {
dirty = true;
shardsIter.remove();
break;
}
}
}
}
}
return dirty;
}
private boolean applyFailedShards(FailedRerouteAllocation allocation) {
boolean dirty = false;
// apply shards might be called several times with the same shard, ignore it
for (ShardRouting failedShard : allocation.failedShards()) {
boolean shardDirty = false;
boolean inRelocation = failedShard.relocatingNodeId() != null;
if (inRelocation) {
RoutingNode routingNode = allocation.routingNodes().nodesToShards().get(failedShard.currentNodeId());
if (routingNode != null) {
Iterator shards = routingNode.iterator();
while (shards.hasNext()) {
MutableShardRouting shard = shards.next();
if (shard.shardId().equals(failedShard.shardId())) {
shardDirty = true;
shard.deassignNode();
shards.remove();
break;
}
}
}
}
String nodeId = inRelocation ? failedShard.relocatingNodeId() : failedShard.currentNodeId();
RoutingNode currentRoutingNode = allocation.routingNodes().nodesToShards().get(nodeId);
if (currentRoutingNode == null) {
// already failed (might be called several times for the same shard)
continue;
}
Iterator shards = currentRoutingNode.iterator();
while (shards.hasNext()) {
MutableShardRouting shard = shards.next();
if (shard.shardId().equals(failedShard.shardId())) {
shardDirty = true;
if (!inRelocation) {
shard.deassignNode();
shards.remove();
} else {
shard.cancelRelocation();
}
break;
}
}
if (!shardDirty) {
continue;
} else {
dirty = true;
}
// if in relocation no need to find a new target, just cancel the relocation.
if (inRelocation) {
continue;
}
// not in relocation so find a new target.
boolean allocated = false;
List sortedNodesLeastToHigh = allocation.routingNodes().sortedNodesLeastToHigh();
for (RoutingNode target : sortedNodesLeastToHigh) {
if (!target.nodeId().equals(failedShard.currentNodeId()) &&
nodeAllocations.canAllocate(failedShard, target, allocation).allocate()) {
target.add(new MutableShardRouting(failedShard.index(), failedShard.id(),
target.nodeId(), failedShard.relocatingNodeId(),
failedShard.primary(), INITIALIZING));
allocated = true;
break;
}
}
if (!allocated) {
// we did not manage to allocate it, put it in the unassigned
allocation.routingNodes().unassigned().add(new MutableShardRouting(failedShard.index(), failedShard.id(),
null, failedShard.primary(), ShardRoutingState.UNASSIGNED));
}
}
return dirty;
}
}