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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;
import org.elasticsearch.cluster.routing.UnassignedInfo.AllocationStatus;
import org.elasticsearch.cluster.routing.allocation.decider.Decision;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import java.io.IOException;
import java.util.Locale;
/**
* An enum which represents the various decision types that can be taken by the
* allocators and deciders for allocating a shard to a node.
*/
public enum AllocationDecision implements Writeable {
/**
* The shard can be allocated to a node.
*/
YES((byte) 0),
/**
* The allocation attempt was throttled for the shard.
*/
THROTTLED((byte) 1),
/**
* The shard cannot be allocated, which can happen for any number of reasons,
* including the allocation deciders gave a NO decision for allocating.
*/
NO((byte) 2),
/**
* The shard could not be rebalanced to another node despite rebalancing
* being allowed, because moving the shard to the other node would not form
* a better cluster balance.
*/
WORSE_BALANCE((byte) 3),
/**
* Waiting on getting shard data from all nodes before making a decision
* about where to allocate the shard.
*/
AWAITING_INFO((byte) 4),
/**
* The allocation decision has been delayed waiting for a replica with a shard copy
* that left the cluster to rejoin.
*/
ALLOCATION_DELAYED((byte) 5),
/**
* The shard was denied allocation because there were no valid shard copies
* found for it amongst the nodes in the cluster.
*/
NO_VALID_SHARD_COPY((byte) 6),
/**
* No attempt was made to allocate the shard
*/
NO_ATTEMPT((byte) 7);
private final byte id;
AllocationDecision(byte id) {
this.id = id;
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeByte(id);
}
public static AllocationDecision readFrom(StreamInput in) throws IOException {
byte id = in.readByte();
switch (id) {
case 0:
return YES;
case 1:
return THROTTLED;
case 2:
return NO;
case 3:
return WORSE_BALANCE;
case 4:
return AWAITING_INFO;
case 5:
return ALLOCATION_DELAYED;
case 6:
return NO_VALID_SHARD_COPY;
case 7:
return NO_ATTEMPT;
default:
throw new IllegalArgumentException("Unknown value [" + id + "]");
}
}
/**
* Gets an {@link AllocationDecision} from a {@link AllocationStatus}.
*/
public static AllocationDecision fromAllocationStatus(AllocationStatus allocationStatus) {
if (allocationStatus == null) {
return YES;
} else {
switch (allocationStatus) {
case DECIDERS_THROTTLED:
return THROTTLED;
case FETCHING_SHARD_DATA:
return AWAITING_INFO;
case DELAYED_ALLOCATION:
return ALLOCATION_DELAYED;
case NO_VALID_SHARD_COPY:
return NO_VALID_SHARD_COPY;
case NO_ATTEMPT:
return NO_ATTEMPT;
default:
assert allocationStatus == AllocationStatus.DECIDERS_NO : "unhandled AllocationStatus type [" + allocationStatus + "]";
return NO;
}
}
}
/**
* Gets an {@link AllocationDecision} from a {@link Decision.Type}
*/
public static AllocationDecision fromDecisionType(Decision.Type type) {
switch (type) {
case YES:
return YES;
case THROTTLE:
return THROTTLED;
default:
assert type == Decision.Type.NO;
return NO;
}
}
@Override
public String toString() {
return super.toString().toLowerCase(Locale.ROOT);
}
}