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Elasticsearch subproject :server
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.cluster.routing.allocation.decider;
import org.elasticsearch.cluster.metadata.IndexMetadata;
import org.elasticsearch.cluster.routing.RecoverySource;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.settings.ClusterSettings;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Setting.Property;
import org.elasticsearch.common.settings.Settings;
import java.util.Locale;
/**
* This allocation decider allows shard allocations / rebalancing via the cluster wide settings
* {@link #CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING} / {@link #CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING} and the per index setting
* {@link #INDEX_ROUTING_ALLOCATION_ENABLE_SETTING} / {@link #INDEX_ROUTING_REBALANCE_ENABLE_SETTING}.
* The per index settings overrides the cluster wide setting.
*
*
* Allocation settings can have the following values (non-casesensitive):
*
* -
NONE
- no shard allocation is allowed.
* -
NEW_PRIMARIES
- only primary shards of new indices are allowed to be allocated
* -
PRIMARIES
- only primary shards are allowed to be allocated
* -
ALL
- all shards are allowed to be allocated
*
*
*
* Rebalancing settings can have the following values (non-casesensitive):
*
* -
NONE
- no shard rebalancing is allowed.
* -
REPLICAS
- only replica shards are allowed to be balanced
* -
PRIMARIES
- only primary shards are allowed to be balanced
* -
ALL
- all shards are allowed to be balanced
*
*
* @see Rebalance
* @see Allocation
*/
public class EnableAllocationDecider extends AllocationDecider {
public static final String NAME = "enable";
public static final Setting CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING = Setting.enumSetting(
Allocation.class,
"cluster.routing.allocation.enable",
Allocation.ALL,
Property.Dynamic,
Property.NodeScope
);
public static final Setting INDEX_ROUTING_ALLOCATION_ENABLE_SETTING = Setting.enumSetting(
Allocation.class,
"index.routing.allocation.enable",
Allocation.ALL,
Property.Dynamic,
Property.IndexScope
);
public static final Setting CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING = Setting.enumSetting(
Rebalance.class,
"cluster.routing.rebalance.enable",
Rebalance.ALL,
Property.Dynamic,
Property.NodeScope
);
public static final Setting INDEX_ROUTING_REBALANCE_ENABLE_SETTING = Setting.enumSetting(
Rebalance.class,
"index.routing.rebalance.enable",
Rebalance.ALL,
Property.Dynamic,
Property.IndexScope
);
private volatile Rebalance enableRebalance;
private volatile Allocation enableAllocation;
public EnableAllocationDecider(Settings settings, ClusterSettings clusterSettings) {
this.enableAllocation = CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING.get(settings);
this.enableRebalance = CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING.get(settings);
clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING, this::setEnableAllocation);
clusterSettings.addSettingsUpdateConsumer(CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING, this::setEnableRebalance);
}
private void setEnableRebalance(Rebalance enableRebalance) {
this.enableRebalance = enableRebalance;
}
private void setEnableAllocation(Allocation enableAllocation) {
this.enableAllocation = enableAllocation;
}
@Override
public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
return canAllocate(shardRouting, allocation);
}
@Override
public Decision canAllocate(ShardRouting shardRouting, RoutingAllocation allocation) {
if (allocation.ignoreDisable()) {
return allocation.decision(
Decision.YES,
NAME,
"explicitly ignoring any disabling of allocation due to manual allocation commands via the reroute API"
);
}
final IndexMetadata indexMetadata = allocation.metadata().getIndexSafe(shardRouting.index());
final Allocation enable;
final boolean usedIndexSetting;
if (INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.exists(indexMetadata.getSettings())) {
enable = INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.get(indexMetadata.getSettings());
usedIndexSetting = true;
} else {
enable = this.enableAllocation;
usedIndexSetting = false;
}
switch (enable) {
case ALL:
return allocation.decision(Decision.YES, NAME, "all allocations are allowed");
case NONE:
return allocation.decision(Decision.NO, NAME, "no allocations are allowed due to %s", setting(enable, usedIndexSetting));
case NEW_PRIMARIES:
if (shardRouting.primary()
&& shardRouting.active() == false
&& shardRouting.recoverySource().getType() != RecoverySource.Type.EXISTING_STORE) {
return allocation.decision(Decision.YES, NAME, "new primary allocations are allowed");
} else {
return allocation.decision(
Decision.NO,
NAME,
"non-new primary allocations are forbidden due to %s",
setting(enable, usedIndexSetting)
);
}
case PRIMARIES:
if (shardRouting.primary()) {
return allocation.decision(Decision.YES, NAME, "primary allocations are allowed");
} else {
return allocation.decision(
Decision.NO,
NAME,
"replica allocations are forbidden due to %s",
setting(enable, usedIndexSetting)
);
}
default:
throw new IllegalStateException("Unknown allocation option");
}
}
@Override
public Decision canRebalance(RoutingAllocation allocation) {
if (allocation.ignoreDisable()) {
return allocation.decision(Decision.YES, NAME, "allocation is explicitly ignoring any disabling of rebalancing");
}
if (enableRebalance == Rebalance.NONE) {
for (IndexMetadata indexMetadata : allocation.metadata()) {
if (INDEX_ROUTING_REBALANCE_ENABLE_SETTING.exists(indexMetadata.getSettings())
&& INDEX_ROUTING_REBALANCE_ENABLE_SETTING.get(indexMetadata.getSettings()) != Rebalance.NONE) {
return allocation.decision(Decision.YES, NAME, "rebalancing is permitted on one or more indices");
}
}
return allocation.decision(Decision.NO, NAME, "no rebalancing is allowed due to %s", setting(enableRebalance, false));
}
return allocation.decision(Decision.YES, NAME, "rebalancing is not globally disabled");
}
@Override
public Decision canRebalance(ShardRouting shardRouting, RoutingAllocation allocation) {
if (allocation.ignoreDisable()) {
return allocation.decision(Decision.YES, NAME, "allocation is explicitly ignoring any disabling of rebalancing");
}
Settings indexSettings = allocation.metadata().getIndexSafe(shardRouting.index()).getSettings();
final Rebalance enable;
final boolean usedIndexSetting;
if (INDEX_ROUTING_REBALANCE_ENABLE_SETTING.exists(indexSettings)) {
enable = INDEX_ROUTING_REBALANCE_ENABLE_SETTING.get(indexSettings);
usedIndexSetting = true;
} else {
enable = this.enableRebalance;
usedIndexSetting = false;
}
switch (enable) {
case ALL:
return allocation.decision(Decision.YES, NAME, "all rebalancing is allowed");
case NONE:
return allocation.decision(Decision.NO, NAME, "no rebalancing is allowed due to %s", setting(enable, usedIndexSetting));
case PRIMARIES:
if (shardRouting.primary()) {
return allocation.decision(Decision.YES, NAME, "primary rebalancing is allowed");
} else {
return allocation.decision(
Decision.NO,
NAME,
"replica rebalancing is forbidden due to %s",
setting(enable, usedIndexSetting)
);
}
case REPLICAS:
if (shardRouting.primary() == false) {
return allocation.decision(Decision.YES, NAME, "replica rebalancing is allowed");
} else {
return allocation.decision(
Decision.NO,
NAME,
"primary rebalancing is forbidden due to %s",
setting(enable, usedIndexSetting)
);
}
default:
throw new IllegalStateException("Unknown rebalance option");
}
}
private static String setting(Allocation allocation, boolean usedIndexSetting) {
StringBuilder buf = new StringBuilder();
if (usedIndexSetting) {
buf.append("index setting [");
buf.append(INDEX_ROUTING_ALLOCATION_ENABLE_SETTING.getKey());
} else {
buf.append("cluster setting [");
buf.append(CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING.getKey());
}
buf.append("=").append(allocation.toString().toLowerCase(Locale.ROOT)).append("]");
return buf.toString();
}
private static String setting(Rebalance rebalance, boolean usedIndexSetting) {
StringBuilder buf = new StringBuilder();
if (usedIndexSetting) {
buf.append("index setting [");
buf.append(INDEX_ROUTING_REBALANCE_ENABLE_SETTING.getKey());
} else {
buf.append("cluster setting [");
buf.append(CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING.getKey());
}
buf.append("=").append(rebalance.toString().toLowerCase(Locale.ROOT)).append("]");
return buf.toString();
}
/**
* Allocation values or rather their string representation to be used used with
* {@link EnableAllocationDecider#CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING} /
* {@link EnableAllocationDecider#INDEX_ROUTING_ALLOCATION_ENABLE_SETTING}
* via cluster / index settings.
*/
public enum Allocation {
NONE,
NEW_PRIMARIES,
PRIMARIES,
ALL;
@Override
public String toString() {
return name().toLowerCase(Locale.ROOT);
}
}
/**
* Rebalance values or rather their string representation to be used used with
* {@link EnableAllocationDecider#CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING} /
* {@link EnableAllocationDecider#INDEX_ROUTING_REBALANCE_ENABLE_SETTING}
* via cluster / index settings.
*/
public enum Rebalance {
NONE,
PRIMARIES,
REPLICAS,
ALL;
@Override
public String toString() {
return name().toLowerCase(Locale.ROOT);
}
}
}