org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementStatusWithUpgradeDomain Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.apache.hadoop.hdfs.server.blockmanagement;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import java.util.Set;
/**
* An implementation of @see BlockPlacementStatus for
* @see BlockPlacementPolicyWithUpgradeDomain
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class BlockPlacementStatusWithUpgradeDomain implements
BlockPlacementStatus {
private final BlockPlacementStatus parentBlockPlacementStatus;
private final Set upgradeDomains;
private final int numberOfReplicas;
private final int upgradeDomainFactor;
/**
* @param parentBlockPlacementStatus the parent class' status
* @param upgradeDomains the set of upgrade domains of the replicas
* @param numberOfReplicas the number of replicas of the block
* @param upgradeDomainFactor the configured upgrade domain factor
*/
public BlockPlacementStatusWithUpgradeDomain(
BlockPlacementStatus parentBlockPlacementStatus,
Set upgradeDomains, int numberOfReplicas,
int upgradeDomainFactor){
this.parentBlockPlacementStatus = parentBlockPlacementStatus;
this.upgradeDomains = upgradeDomains;
this.numberOfReplicas = numberOfReplicas;
this.upgradeDomainFactor = upgradeDomainFactor;
}
@Override
public boolean isPlacementPolicySatisfied() {
return parentBlockPlacementStatus.isPlacementPolicySatisfied() &&
isUpgradeDomainPolicySatisfied();
}
private boolean isUpgradeDomainPolicySatisfied() {
if (numberOfReplicas <= upgradeDomainFactor) {
return (numberOfReplicas <= upgradeDomains.size());
} else {
return upgradeDomains.size() >= upgradeDomainFactor;
}
}
@Override
public String getErrorDescription() {
if (isPlacementPolicySatisfied()) {
return null;
}
StringBuilder errorDescription = new StringBuilder();
if (!parentBlockPlacementStatus.isPlacementPolicySatisfied()) {
errorDescription.append(parentBlockPlacementStatus.getErrorDescription());
}
if (!isUpgradeDomainPolicySatisfied()) {
if (errorDescription.length() != 0) {
errorDescription.append(" ");
}
errorDescription.append("The block has " + numberOfReplicas +
" replicas. But it only has " + upgradeDomains.size() +
" upgrade domains " + upgradeDomains +".");
}
return errorDescription.toString();
}
@Override
public int getAdditionalReplicasRequired() {
if (isPlacementPolicySatisfied()) {
return 0;
} else {
// It is possible for a block to have the correct number of upgrade
// domains, but only a single rack, or be on multiple racks, but only in
// one upgrade domain.
int parent = parentBlockPlacementStatus.getAdditionalReplicasRequired();
int child;
if (numberOfReplicas <= upgradeDomainFactor) {
child = numberOfReplicas - upgradeDomains.size();
} else {
child = upgradeDomainFactor - upgradeDomains.size();
}
return Math.max(parent, child);
}
}
}