/**
* 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.datanode;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.hdfs.server.common.HdfsConstants;
import org.apache.hadoop.hdfs.server.common.UpgradeObject;
import org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol;
import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
import org.apache.hadoop.hdfs.server.protocol.UpgradeCommand;
import org.apache.hadoop.util.StringUtils;
import java.io.IOException;
import java.net.SocketTimeoutException;
/**
* Base class for data-node upgrade objects.
* Data-node upgrades are run in separate threads.
*/
public abstract class UpgradeObjectDatanode extends UpgradeObject implements Runnable {
private DataNode dataNode = null;
public HdfsConstants.NodeType getType() {
return HdfsConstants.NodeType.DATA_NODE;
}
protected DataNode getDatanode() {
return dataNode;
}
void setDatanode(DataNode dataNode) {
this.dataNode = dataNode;
}
/**
* Specifies how the upgrade is performed.
* @throws IOException
*/
public abstract void doUpgrade() throws IOException;
/**
* Specifies what to do before the upgrade is started.
*
* The default implementation checks whether the data-node missed the upgrade
* and throws an exception if it did. This leads to the data-node shutdown.
*
* Data-nodes usually start distributed upgrade when the name-node replies
* to its heartbeat with a start upgrade command.
* Sometimes though, e.g. when a data-node missed the upgrade and wants to
* catchup with the rest of the cluster, it is necessary to initiate the
* upgrade directly on the data-node, since the name-node might not ever
* start it. An override of this method should then return true.
* And the upgrade will start after data-ndoe registration but before sending
* its first heartbeat.
*
* @param nsInfo name-node versions, verify that the upgrade
* object can talk to this name-node version if necessary.
*
* @throws IOException
* @return true if data-node itself should start the upgrade or
* false if it should wait until the name-node starts the upgrade.
*/
boolean preUpgradeAction(NamespaceInfo nsInfo) throws IOException {
int nsUpgradeVersion = nsInfo.getDistributedUpgradeVersion();
if(nsUpgradeVersion >= getVersion())
return false; // name-node will perform the upgrade
// Missed the upgrade. Report problem to the name-node and throw exception
String errorMsg =
"\n Data-node missed a distributed upgrade and will shutdown."
+ "\n " + getDescription() + "."
+ " Name-node version = " + nsInfo.getLayoutVersion() + ".";
DataNode.LOG.fatal( errorMsg );
try {
dataNode.namenode.errorReport(dataNode.dnRegistration,
DatanodeProtocol.NOTIFY, errorMsg);
} catch(SocketTimeoutException e) { // namenode is busy
DataNode.LOG.info("Problem connecting to server: "
+ dataNode.getNameNodeAddr());
}
throw new IOException(errorMsg);
}
public void run() {
assert dataNode != null : "UpgradeObjectDatanode.dataNode is null";
while(dataNode.shouldRun) {
try {
doUpgrade();
} catch(Exception e) {
DataNode.LOG.error(StringUtils.stringifyException(e));
}
break;
}
// report results
if(getUpgradeStatus() < 100) {
DataNode.LOG.info("\n Distributed upgrade for DataNode version "
+ getVersion() + " to current LV "
+ FSConstants.LAYOUT_VERSION + " cannot be completed");
}
// Complete the upgrade by calling the manager method
try {
dataNode.upgradeManager.completeUpgrade();
} catch(IOException e) {
DataNode.LOG.error(StringUtils.stringifyException(e));
}
}
/**
* Complete upgrade and return a status complete command for broadcasting.
*
* Data-nodes finish upgrade at different times.
* The data-node needs to re-confirm with the name-node that the upgrade
* is complete while other nodes are still upgrading.
*/
public UpgradeCommand completeUpgrade() throws IOException {
return new UpgradeCommand(UpgradeCommand.UC_ACTION_REPORT_STATUS,
getVersion(), (short)100);
}
}