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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* 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.IndexMetaData;
import org.elasticsearch.cluster.routing.RoutingNode;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.UnassignedInfo;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.settings.Setting;
/**
* An allocation decider that prevents shards from being allocated on any node if the shards allocation has been retried N times without
* success. This means if a shard has been INITIALIZING N times in a row without being moved to STARTED the shard will be ignored until
* the setting for {@code index.allocation.max_retry} is raised. The default value is {@code 5}.
* Note: This allocation decider also allows allocation of repeatedly failing shards when the {@code /_cluster/reroute?retry_failed=true}
* API is manually invoked. This allows single retries without raising the limits.
*
*/
public class MaxRetryAllocationDecider extends AllocationDecider {
public static final Setting SETTING_ALLOCATION_MAX_RETRY = Setting.intSetting("index.allocation.max_retries", 5, 0,
Setting.Property.Dynamic, Setting.Property.IndexScope, Setting.Property.NotCopyableOnResize);
public static final String NAME = "max_retry";
@Override
public Decision canAllocate(ShardRouting shardRouting, RoutingAllocation allocation) {
final UnassignedInfo unassignedInfo = shardRouting.unassignedInfo();
final Decision decision;
if (unassignedInfo != null && unassignedInfo.getNumFailedAllocations() > 0) {
final IndexMetaData indexMetaData = allocation.metaData().getIndexSafe(shardRouting.index());
final int maxRetry = SETTING_ALLOCATION_MAX_RETRY.get(indexMetaData.getSettings());
if (unassignedInfo.getNumFailedAllocations() >= maxRetry) {
decision = allocation.decision(Decision.NO, NAME, "shard has exceeded the maximum number of retries [%d] on " +
"failed allocation attempts - manually call [/_cluster/reroute?retry_failed=true] to retry, [%s]",
maxRetry, unassignedInfo.toString());
} else {
decision = allocation.decision(Decision.YES, NAME, "shard has failed allocating [%d] times but [%d] retries are allowed",
unassignedInfo.getNumFailedAllocations(), maxRetry);
}
} else {
decision = allocation.decision(Decision.YES, NAME, "shard has no previous failures");
}
return decision;
}
@Override
public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
return canAllocate(shardRouting, allocation);
}
@Override
public Decision canForceAllocatePrimary(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) {
assert shardRouting.primary() : "must not call canForceAllocatePrimary on a non-primary shard " + shardRouting;
// check if we have passed the maximum retry threshold through canAllocate,
// if so, we don't want to force the primary allocation here
return canAllocate(shardRouting, node, allocation);
}
}