/**
* 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.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.server.namenode.Namesystem;
import java.util.Map;
/**
* Manage node decommissioning.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
class DecommissionManager {
static final Log LOG = LogFactory.getLog(DecommissionManager.class);
private final Namesystem namesystem;
private final BlockManager blockmanager;
DecommissionManager(final Namesystem namesystem,
final BlockManager blockmanager) {
this.namesystem = namesystem;
this.blockmanager = blockmanager;
}
/**
* Periodically check decommission status.
*/
class Monitor implements Runnable {
/**
* recheckInterval is how often namenode checks
* if a node has finished decommission
*/
private final long recheckInterval;
/**
* The number of decommission nodes to check for each interval
*/
private final int numNodesPerCheck;
/**
* firstkey can be initialized to anything.
*/
private String firstkey = "";
Monitor(int recheckIntervalInSecond, int numNodesPerCheck) {
this.recheckInterval = recheckIntervalInSecond * 1000L;
this.numNodesPerCheck = numNodesPerCheck;
}
/**
* Check decommission status of numNodesPerCheck nodes
* for every recheckInterval milliseconds.
*/
@Override
public void run() {
for (; namesystem.isRunning(); ) {
check();
try {
Thread.sleep(recheckInterval);
} catch (InterruptedException ie) {
LOG.warn(this.getClass().getSimpleName() + " interrupted: " + ie);
}
}
}
private void check() {
final DatanodeManager dm = blockmanager.getDatanodeManager();
int count = 0;
for (Map.Entry<String, DatanodeDescriptor> entry : dm
.getDatanodeCyclicIteration(firstkey)) {
final DatanodeDescriptor d = entry.getValue();
firstkey = entry.getKey();
if (d.isDecommissionInProgress()) {
try {
dm.checkDecommissionState(d);
} catch (Exception e) {
LOG.warn("entry=" + entry, e);
}
if (++count == numNodesPerCheck) {
return;
}
}
}
}
}
}