/**
* 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 java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import com.google.common.annotations.VisibleForTesting;
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.protocol.Block;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.server.namenode.CachedBlock;
import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
import org.apache.hadoop.hdfs.server.protocol.StorageReport;
import org.apache.hadoop.hdfs.util.LightWeightHashSet;
import org.apache.hadoop.util.IntrusiveCollection;
import org.apache.hadoop.util.Time;
import com.google.common.annotations.VisibleForTesting;
/**
* This class extends the DatanodeInfo class with ephemeral information (eg
* health, capacity, what blocks are associated with the Datanode) that is
* private to the Namenode, ie this class is not exposed to clients.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class DatanodeDescriptor extends DatanodeInfo {
public static final Log LOG = LogFactory.getLog(DatanodeDescriptor.class);
public static final DatanodeDescriptor[] EMPTY_ARRAY = {};
// Stores status of decommissioning.
// If node is not decommissioning, do not use this object for anything.
public final DecommissioningStatus decommissioningStatus = new DecommissioningStatus();
/** Block and targets pair */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public static class BlockTargetPair {
public final Block block;
public final DatanodeStorageInfo[] targets;
BlockTargetPair(Block block, DatanodeStorageInfo[] targets) {
this.block = block;
this.targets = targets;
}
}
/** A BlockTargetPair queue. */
private static class BlockQueue<E> {
private final Queue<E> blockq = new LinkedList<E>();
/** Size of the queue */
synchronized int size() {return blockq.size();}
/** Enqueue */
synchronized boolean offer(E e) {
return blockq.offer(e);
}
/** Dequeue */
synchronized List<E> poll(int numBlocks) {
if (numBlocks <= 0 || blockq.isEmpty()) {
return null;
}
List<E> results = new ArrayList<E>();
for(; !blockq.isEmpty() && numBlocks > 0; numBlocks--) {
results.add(blockq.poll());
}
return results;
}
/**
* Returns <tt>true</tt> if the queue contains the specified element.
*/
boolean contains(E e) {
return blockq.contains(e);
}
synchronized void clear() {
blockq.clear();
}
}
private final Map<String, DatanodeStorageInfo> storageMap =
new HashMap<String, DatanodeStorageInfo>();
/**
* A list of CachedBlock objects on this datanode.
*/
public static class CachedBlocksList extends IntrusiveCollection<CachedBlock> {
public enum Type {
PENDING_CACHED,
CACHED,
PENDING_UNCACHED
}
private final DatanodeDescriptor datanode;
private final Type type;
CachedBlocksList(DatanodeDescriptor datanode, Type type) {
this.datanode = datanode;
this.type = type;
}
public DatanodeDescriptor getDatanode() {
return datanode;
}
public Type getType() {
return type;
}
}
/**
* The blocks which we want to cache on this DataNode.
*/
private final CachedBlocksList pendingCached =
new CachedBlocksList(this, CachedBlocksList.Type.PENDING_CACHED);
/**
* The blocks which we know are cached on this datanode.
* This list is updated by periodic cache reports.
*/
private final CachedBlocksList cached =
new CachedBlocksList(this, CachedBlocksList.Type.CACHED);
/**
* The blocks which we want to uncache on this DataNode.
*/
private final CachedBlocksList pendingUncached =
new CachedBlocksList(this, CachedBlocksList.Type.PENDING_UNCACHED);
public CachedBlocksList getPendingCached() {
return pendingCached;
}
public CachedBlocksList getCached() {
return cached;
}
public CachedBlocksList getPendingUncached() {
return pendingUncached;
}
/**
* The time when the last batch of caching directives was sent, in
* monotonic milliseconds.
*/
private long lastCachingDirectiveSentTimeMs;
// isAlive == heartbeats.contains(this)
// This is an optimization, because contains takes O(n) time on Arraylist
public boolean isAlive = false;
public boolean needKeyUpdate = false;
// A system administrator can tune the balancer bandwidth parameter
// (dfs.balance.bandwidthPerSec) dynamically by calling
// "dfsadmin -setBalanacerBandwidth <newbandwidth>", at which point the
// following 'bandwidth' variable gets updated with the new value for each
// node. Once the heartbeat command is issued to update the value on the
// specified datanode, this value will be set back to 0.
private long bandwidth;
/** A queue of blocks to be replicated by this datanode */
private final BlockQueue<BlockTargetPair> replicateBlocks = new BlockQueue<BlockTargetPair>();
/** A queue of blocks to be recovered by this datanode */
private final BlockQueue<BlockInfoUnderConstruction> recoverBlocks =
new BlockQueue<BlockInfoUnderConstruction>();
/** A set of blocks to be invalidated by this datanode */
private final LightWeightHashSet<Block> invalidateBlocks = new LightWeightHashSet<Block>();
/* Variables for maintaining number of blocks scheduled to be written to
* this storage. This count is approximate and might be slightly bigger
* in case of errors (e.g. datanode does not report if an error occurs
* while writing the block).
*/
private int currApproxBlocksScheduled = 0;
private int prevApproxBlocksScheduled = 0;
private long lastBlocksScheduledRollTime = 0;
private static final int BLOCKS_SCHEDULED_ROLL_INTERVAL = 600*1000; //10min
private int volumeFailures = 0;
/**
* When set to true, the node is not in include list and is not allowed
* to communicate with the namenode
*/
private boolean disallowed = false;
/**
* DatanodeDescriptor constructor
* @param nodeID id of the data node
*/
public DatanodeDescriptor(DatanodeID nodeID) {
super(nodeID);
updateHeartbeat(StorageReport.EMPTY_ARRAY, 0L, 0L, 0, 0);
}
/**
* DatanodeDescriptor constructor
* @param nodeID id of the data node
* @param networkLocation location of the data node in network
*/
public DatanodeDescriptor(DatanodeID nodeID,
String networkLocation) {
super(nodeID, networkLocation);
updateHeartbeat(StorageReport.EMPTY_ARRAY, 0L, 0L, 0, 0);
}
/**
* Add data-node to the block. Add block to the head of the list of blocks
* belonging to the data-node.
*/
public boolean addBlock(String storageID, BlockInfo b) {
DatanodeStorageInfo s = getStorageInfo(storageID);
if (s != null) {
return s.addBlock(b);
}
return false;
}
@VisibleForTesting
public DatanodeStorageInfo getStorageInfo(String storageID) {
synchronized (storageMap) {
return storageMap.get(storageID);
}
}
DatanodeStorageInfo[] getStorageInfos() {
synchronized (storageMap) {
final Collection<DatanodeStorageInfo> storages = storageMap.values();
return storages.toArray(new DatanodeStorageInfo[storages.size()]);
}
}
boolean hasStaleStorages() {
synchronized (storageMap) {
for (DatanodeStorageInfo storage : storageMap.values()) {
if (storage.areBlockContentsStale()) {
return true;
}
}
return false;
}
}
/**
* Remove block from the list of blocks belonging to the data-node. Remove
* data-node from the block.
*/
boolean removeBlock(BlockInfo b) {
int index = b.findStorageInfo(this);
// if block exists on this datanode
if (index >= 0) {
DatanodeStorageInfo s = b.getStorageInfo(index);
if (s != null) {
return s.removeBlock(b);
}
}
return false;
}
/**
* Remove block from the list of blocks belonging to the data-node. Remove
* data-node from the block.
*/
boolean removeBlock(String storageID, BlockInfo b) {
DatanodeStorageInfo s = getStorageInfo(storageID);
if (s != null) {
return s.removeBlock(b);
}
return false;
}
/**
* Replace specified old block with a new one in the DataNodeDescriptor.
*
* @param oldBlock - block to be replaced
* @param newBlock - a replacement block
* @return the new block
*/
public BlockInfo replaceBlock(BlockInfo oldBlock, BlockInfo newBlock) {
int index = oldBlock.findStorageInfo(this);
DatanodeStorageInfo s = oldBlock.getStorageInfo(index);
boolean done = s.removeBlock(oldBlock);
assert done : "Old block should belong to the data-node when replacing";
done = s.addBlock(newBlock);
assert done : "New block should not belong to the data-node when replacing";
return newBlock;
}
public void resetBlocks() {
setCapacity(0);
setRemaining(0);
setBlockPoolUsed(0);
setDfsUsed(0);
setXceiverCount(0);
this.invalidateBlocks.clear();
this.volumeFailures = 0;
// pendingCached, cached, and pendingUncached are protected by the
// FSN lock.
this.pendingCached.clear();
this.cached.clear();
this.pendingUncached.clear();
}
public void clearBlockQueues() {
synchronized (invalidateBlocks) {
this.invalidateBlocks.clear();
this.recoverBlocks.clear();
this.replicateBlocks.clear();
}
// pendingCached, cached, and pendingUncached are protected by the
// FSN lock.
this.pendingCached.clear();
this.cached.clear();
this.pendingUncached.clear();
}
public int numBlocks() {
int blocks = 0;
for (DatanodeStorageInfo entry : getStorageInfos()) {
blocks += entry.numBlocks();
}
return blocks;
}
/**
* Updates stats from datanode heartbeat.
*/
public void updateHeartbeat(StorageReport[] reports, long cacheCapacity,
long cacheUsed, int xceiverCount, int volFailures) {
long totalCapacity = 0;
long totalRemaining = 0;
long totalBlockPoolUsed = 0;
long totalDfsUsed = 0;
setCacheCapacity(cacheCapacity);
setCacheUsed(cacheUsed);
setXceiverCount(xceiverCount);
setLastUpdate(Time.now());
this.volumeFailures = volFailures;
for (StorageReport report : reports) {
DatanodeStorageInfo storage = updateStorage(report.getStorage());
storage.receivedHeartbeat(report);
totalCapacity += report.getCapacity();
totalRemaining += report.getRemaining();
totalBlockPoolUsed += report.getBlockPoolUsed();
totalDfsUsed += report.getDfsUsed();
}
rollBlocksScheduled(getLastUpdate());
// Update total metrics for the node.
setCapacity(totalCapacity);
setRemaining(totalRemaining);
setBlockPoolUsed(totalBlockPoolUsed);
setDfsUsed(totalDfsUsed);
}
private static class BlockIterator implements Iterator<BlockInfo> {
private int index = 0;
private final List<Iterator<BlockInfo>> iterators;
private BlockIterator(final DatanodeStorageInfo... storages) {
List<Iterator<BlockInfo>> iterators = new ArrayList<Iterator<BlockInfo>>();
for (DatanodeStorageInfo e : storages) {
iterators.add(e.getBlockIterator());
}
this.iterators = Collections.unmodifiableList(iterators);
}
@Override
public boolean hasNext() {
update();
return !iterators.isEmpty() && iterators.get(index).hasNext();
}
@Override
public BlockInfo next() {
update();
return iterators.get(index).next();
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove unsupported.");
}
private void update() {
while(index < iterators.size() - 1 && !iterators.get(index).hasNext()) {
index++;
}
}
}
Iterator<BlockInfo> getBlockIterator() {
return new BlockIterator(getStorageInfos());
}
Iterator<BlockInfo> getBlockIterator(final String storageID) {
return new BlockIterator(getStorageInfo(storageID));
}
/**
* Store block replication work.
*/
void addBlockToBeReplicated(Block block, DatanodeStorageInfo[] targets) {
assert(block != null && targets != null && targets.length > 0);
replicateBlocks.offer(new BlockTargetPair(block, targets));
}
/**
* Store block recovery work.
*/
void addBlockToBeRecovered(BlockInfoUnderConstruction block) {
if(recoverBlocks.contains(block)) {
// this prevents adding the same block twice to the recovery queue
BlockManager.LOG.info(block + " is already in the recovery queue");
return;
}
recoverBlocks.offer(block);
}
/**
* Store block invalidation work.
*/
void addBlocksToBeInvalidated(List<Block> blocklist) {
assert(blocklist != null && blocklist.size() > 0);
synchronized (invalidateBlocks) {
for(Block blk : blocklist) {
invalidateBlocks.add(blk);
}
}
}
/**
* The number of work items that are pending to be replicated
*/
int getNumberOfBlocksToBeReplicated() {
return replicateBlocks.size();
}
/**
* The number of block invalidation items that are pending to
* be sent to the datanode
*/
int getNumberOfBlocksToBeInvalidated() {
synchronized (invalidateBlocks) {
return invalidateBlocks.size();
}
}
public List<BlockTargetPair> getReplicationCommand(int maxTransfers) {
return replicateBlocks.poll(maxTransfers);
}
public BlockInfoUnderConstruction[] getLeaseRecoveryCommand(int maxTransfers) {
List<BlockInfoUnderConstruction> blocks = recoverBlocks.poll(maxTransfers);
if(blocks == null)
return null;
return blocks.toArray(new BlockInfoUnderConstruction[blocks.size()]);
}
/**
* Remove the specified number of blocks to be invalidated
*/
public Block[] getInvalidateBlocks(int maxblocks) {
synchronized (invalidateBlocks) {
Block[] deleteList = invalidateBlocks.pollToArray(new Block[Math.min(
invalidateBlocks.size(), maxblocks)]);
return deleteList.length == 0 ? null : deleteList;
}
}
/**
* @return Approximate number of blocks currently scheduled to be written
* to this datanode.
*/
public int getBlocksScheduled() {
return currApproxBlocksScheduled + prevApproxBlocksScheduled;
}
/** Increment the number of blocks scheduled. */
void incrementBlocksScheduled() {
currApproxBlocksScheduled++;
}
/** Decrement the number of blocks scheduled. */
void decrementBlocksScheduled() {
if (prevApproxBlocksScheduled > 0) {
prevApproxBlocksScheduled--;
} else if (currApproxBlocksScheduled > 0) {
currApproxBlocksScheduled--;
}
// its ok if both counters are zero.
}
/** Adjusts curr and prev number of blocks scheduled every few minutes. */
private void rollBlocksScheduled(long now) {
if (now - lastBlocksScheduledRollTime > BLOCKS_SCHEDULED_ROLL_INTERVAL) {
prevApproxBlocksScheduled = currApproxBlocksScheduled;
currApproxBlocksScheduled = 0;
lastBlocksScheduledRollTime = now;
}
}
@Override
public int hashCode() {
// Super implementation is sufficient
return super.hashCode();
}
@Override
public boolean equals(Object obj) {
// Sufficient to use super equality as datanodes are uniquely identified
// by DatanodeID
return (this == obj) || super.equals(obj);
}
/** Decommissioning status */
public class DecommissioningStatus {
private int underReplicatedBlocks;
private int decommissionOnlyReplicas;
private int underReplicatedInOpenFiles;
private long startTime;
synchronized void set(int underRep,
int onlyRep, int underConstruction) {
if (isDecommissionInProgress() == false) {
return;
}
underReplicatedBlocks = underRep;
decommissionOnlyReplicas = onlyRep;
underReplicatedInOpenFiles = underConstruction;
}
/** @return the number of under-replicated blocks */
public synchronized int getUnderReplicatedBlocks() {
if (isDecommissionInProgress() == false) {
return 0;
}
return underReplicatedBlocks;
}
/** @return the number of decommission-only replicas */
public synchronized int getDecommissionOnlyReplicas() {
if (isDecommissionInProgress() == false) {
return 0;
}
return decommissionOnlyReplicas;
}
/** @return the number of under-replicated blocks in open files */
public synchronized int getUnderReplicatedInOpenFiles() {
if (isDecommissionInProgress() == false) {
return 0;
}
return underReplicatedInOpenFiles;
}
/** Set start time */
public synchronized void setStartTime(long time) {
startTime = time;
}
/** @return start time */
public synchronized long getStartTime() {
if (isDecommissionInProgress() == false) {
return 0;
}
return startTime;
}
} // End of class DecommissioningStatus
/**
* Set the flag to indicate if this datanode is disallowed from communicating
* with the namenode.
*/
public void setDisallowed(boolean flag) {
disallowed = flag;
}
/** Is the datanode disallowed from communicating with the namenode? */
public boolean isDisallowed() {
return disallowed;
}
/**
* @return number of failed volumes in the datanode.
*/
public int getVolumeFailures() {
return volumeFailures;
}
/**
* @param nodeReg DatanodeID to update registration for.
*/
@Override
public void updateRegInfo(DatanodeID nodeReg) {
super.updateRegInfo(nodeReg);
// must re-process IBR after re-registration
for(DatanodeStorageInfo storage : getStorageInfos()) {
storage.setBlockReportCount(0);
}
}
/**
* @return balancer bandwidth in bytes per second for this datanode
*/
public long getBalancerBandwidth() {
return this.bandwidth;
}
/**
* @param bandwidth balancer bandwidth in bytes per second for this datanode
*/
public void setBalancerBandwidth(long bandwidth) {
this.bandwidth = bandwidth;
}
@Override
public String dumpDatanode() {
StringBuilder sb = new StringBuilder(super.dumpDatanode());
int repl = replicateBlocks.size();
if (repl > 0) {
sb.append(" ").append(repl).append(" blocks to be replicated;");
}
int inval = invalidateBlocks.size();
if (inval > 0) {
sb.append(" ").append(inval).append(" blocks to be invalidated;");
}
int recover = recoverBlocks.size();
if (recover > 0) {
sb.append(" ").append(recover).append(" blocks to be recovered;");
}
return sb.toString();
}
DatanodeStorageInfo updateStorage(DatanodeStorage s) {
synchronized (storageMap) {
DatanodeStorageInfo storage = storageMap.get(s.getStorageID());
if (storage == null) {
LOG.info("Adding new storage ID " + s.getStorageID() +
" for DN " + getXferAddr());
storage = new DatanodeStorageInfo(this, s);
storageMap.put(s.getStorageID(), storage);
} else if (storage.getState() != s.getState() ||
storage.getStorageType() != s.getStorageType()) {
// For backwards compatibility, make sure that the type and
// state are updated. Some reports from older datanodes do
// not include these fields so we may have assumed defaults.
// This check can be removed in the next major release after
// 2.4.
storage.updateFromStorage(s);
storageMap.put(storage.getStorageID(), storage);
}
return storage;
}
}
/**
* @return The time at which we last sent caching directives to this
* DataNode, in monotonic milliseconds.
*/
public long getLastCachingDirectiveSentTimeMs() {
return this.lastCachingDirectiveSentTimeMs;
}
/**
* @param time The time at which we last sent caching directives to this
* DataNode, in monotonic milliseconds.
*/
public void setLastCachingDirectiveSentTimeMs(long time) {
this.lastCachingDirectiveSentTimeMs = time;
}
}