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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.
*/
package org.elasticsearch.cluster.routing.allocation.decider;
import org.elasticsearch.cluster.metadata.SnapshotMetaData;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.ImmutableSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.node.settings.NodeSettingsService;
/**
* This {@link org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider} prevents shards that
* are currently been snapshotted to be moved to other nodes.
*/
public class SnapshotInProgressAllocationDecider extends AllocationDecider {
public static final String NAME = "snapshot_in_progress";
/**
* Disables relocation of shards that are currently being snapshotted.
*/
public static final String CLUSTER_ROUTING_ALLOCATION_SNAPSHOT_RELOCATION_ENABLED = "cluster.routing.allocation.snapshot.relocation_enabled";
class ApplySettings implements NodeSettingsService.Listener {
@Override
public void onRefreshSettings(Settings settings) {
boolean newEnableRelocation = settings.getAsBoolean(CLUSTER_ROUTING_ALLOCATION_SNAPSHOT_RELOCATION_ENABLED, enableRelocation);
if (newEnableRelocation != enableRelocation) {
logger.info("updating [{}] from [{}], to [{}]", CLUSTER_ROUTING_ALLOCATION_SNAPSHOT_RELOCATION_ENABLED, enableRelocation, newEnableRelocation);
enableRelocation = newEnableRelocation;
}
}
}
private volatile boolean enableRelocation = false;
/**
* Creates a new {@link org.elasticsearch.cluster.routing.allocation.decider.SnapshotInProgressAllocationDecider} instance
*/
public SnapshotInProgressAllocationDecider() {
this(ImmutableSettings.Builder.EMPTY_SETTINGS);
}
/**
* Creates a new {@link org.elasticsearch.cluster.routing.allocation.decider.SnapshotInProgressAllocationDecider} instance from given settings
*
* @param settings {@link org.elasticsearch.common.settings.Settings} to use
*/
public SnapshotInProgressAllocationDecider(Settings settings) {
this(settings, new NodeSettingsService(settings));
}
@Inject
public SnapshotInProgressAllocationDecider(Settings settings, NodeSettingsService nodeSettingsService) {
super(settings);
enableRelocation = settings.getAsBoolean(CLUSTER_ROUTING_ALLOCATION_SNAPSHOT_RELOCATION_ENABLED, enableRelocation);
nodeSettingsService.addListener(new ApplySettings());
}
/**
* Returns a {@link Decision} whether the given shard routing can be
* re-balanced to the given allocation. The default is
* {@link Decision#ALWAYS}.
*/
public Decision canRebalance(ShardRouting shardRouting, RoutingAllocation allocation) {
return canMove(shardRouting, allocation);
}
/**
* Returns a {@link Decision} whether the given shard routing can be
* allocated on the given node. The default is {@link Decision#ALWAYS}.
*/
public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
return canMove(shardRouting, allocation);
}
private Decision canMove(ShardRouting shardRouting, RoutingAllocation allocation) {
if (!enableRelocation && shardRouting.primary()) {
// Only primary shards are snapshotted
SnapshotMetaData snapshotMetaData = allocation.metaData().custom(SnapshotMetaData.TYPE);
if (snapshotMetaData == null) {
// Snapshots are not running
return allocation.decision(Decision.YES, NAME, "no snapshots are currently running");
}
for (SnapshotMetaData.Entry snapshot : snapshotMetaData.entries()) {
SnapshotMetaData.ShardSnapshotStatus shardSnapshotStatus = snapshot.shards().get(shardRouting.shardId());
if (shardSnapshotStatus != null && !shardSnapshotStatus.state().completed() && shardSnapshotStatus.nodeId() != null && shardSnapshotStatus.nodeId().equals(shardRouting.currentNodeId())) {
logger.trace("Preventing snapshotted shard [{}] to be moved from node [{}]", shardRouting.shardId(), shardSnapshotStatus.nodeId());
return allocation.decision(Decision.NO, NAME, "snapshot for shard [%s] is currently running on node [%s]",
shardRouting.shardId(), shardSnapshotStatus.nodeId());
}
}
}
return allocation.decision(Decision.YES, NAME, "shard not primary or relocation disabled");
}
}