/**
* 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.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Set;
import java.util.TreeSet;
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.util.LightWeightHashSet;
import org.apache.hadoop.util.Time;
/**
* 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 {
// Stores status of decommissioning.
// If node is not decommissioning, do not use this object for anything.
public DecommissioningStatus decommissioningStatus = new DecommissioningStatus();
/** Block and targets pair */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public static class BlockTargetPair {
public final Block block;
public final DatanodeDescriptor[] targets;
BlockTargetPair(Block block, DatanodeDescriptor[] 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 volatile BlockInfo blockList = null;
private int numBlocks = 0;
// isAlive == heartbeats.contains(this)
// This is an optimization, because contains takes O(n) time on Arraylist
public boolean isAlive = false;
public boolean needKeyUpdate = false;
/**
* Set to false on any NN failover, and reset to true
* whenever a block report is received.
*/
private boolean heartbeatedSinceFailover = false;
/**
* At startup or at any failover, the DNs in the cluster may
* have pending block deletions from a previous incarnation
* of the NameNode. Thus, we consider their block contents
* stale until we have received a block report. When a DN
* is considered stale, any replicas on it are transitively
* considered stale. If any block has at least one stale replica,
* then no invalidations will be processed for this block.
* See HDFS-1972.
*/
private boolean blockContentsStale = true;
// 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 BlockQueue<BlockTargetPair> replicateBlocks = new BlockQueue<BlockTargetPair>();
/** A queue of blocks to be recovered by this datanode */
private BlockQueue<BlockInfoUnderConstruction> recoverBlocks =
new BlockQueue<BlockInfoUnderConstruction>();
/** A set of blocks to be invalidated by this datanode */
private LightWeightHashSet<Block> invalidateBlocks = new LightWeightHashSet<Block>();
/* Variables for maintaining number of blocks scheduled to be written to
* this datanode. 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;
/** Set to false after processing first block report */
private boolean firstBlockReport = true;
/**
* 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) {
this(nodeID, 0L, 0L, 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) {
this(nodeID, networkLocation, 0L, 0L, 0L, 0L, 0, 0);
}
/**
* DatanodeDescriptor constructor
* @param nodeID id of the data node
* @param capacity capacity of the data node
* @param dfsUsed space used by the data node
* @param remaining remaining capacity of the data node
* @param bpused space used by the block pool corresponding to this namenode
* @param xceiverCount # of data transfers at the data node
*/
public DatanodeDescriptor(DatanodeID nodeID,
long capacity,
long dfsUsed,
long remaining,
long bpused,
int xceiverCount,
int failedVolumes) {
super(nodeID);
updateHeartbeat(capacity, dfsUsed, remaining, bpused, xceiverCount,
failedVolumes);
}
/**
* DatanodeDescriptor constructor
* @param nodeID id of the data node
* @param networkLocation location of the data node in network
* @param capacity capacity of the data node, including space used by non-dfs
* @param dfsUsed the used space by dfs datanode
* @param remaining remaining capacity of the data node
* @param bpused space used by the block pool corresponding to this namenode
* @param xceiverCount # of data transfers at the data node
*/
public DatanodeDescriptor(DatanodeID nodeID,
String networkLocation,
long capacity,
long dfsUsed,
long remaining,
long bpused,
int xceiverCount,
int failedVolumes) {
super(nodeID, networkLocation);
updateHeartbeat(capacity, dfsUsed, remaining, bpused, xceiverCount,
failedVolumes);
}
/**
* Add datanode to the block.
* Add block to the head of the list of blocks belonging to the data-node.
*/
public boolean addBlock(BlockInfo b) {
if(!b.addNode(this))
return false;
// add to the head of the data-node list
blockList = b.listInsert(blockList, this);
numBlocks++;
return true;
}
/**
* Remove block from the list of blocks belonging to the data-node.
* Remove datanode from the block.
*/
public boolean removeBlock(BlockInfo b) {
blockList = b.listRemove(blockList, this);
if ( b.removeNode(this) ) {
numBlocks--;
return true;
} else {
return false;
}
}
/**
* Move block to the head of the list of blocks belonging to the data-node.
* @return the index of the head of the blockList
*/
int moveBlockToHead(BlockInfo b, int curIndex, int headIndex) {
blockList = b.moveBlockToHead(blockList, this, curIndex, headIndex);
return curIndex;
}
/**
* Used for testing only
* @return the head of the blockList
*/
protected BlockInfo getHead(){
return blockList;
}
/**
* 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) {
boolean done = removeBlock(oldBlock);
assert done : "Old block should belong to the data-node when replacing";
done = 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.blockList = null;
this.invalidateBlocks.clear();
this.volumeFailures = 0;
}
public void clearBlockQueues() {
synchronized (invalidateBlocks) {
this.invalidateBlocks.clear();
this.recoverBlocks.clear();
this.replicateBlocks.clear();
}
}
public int numBlocks() {
return numBlocks;
}
/**
* Updates stats from datanode heartbeat.
*/
public void updateHeartbeat(long capacity, long dfsUsed, long remaining,
long blockPoolUsed, int xceiverCount, int volFailures) {
setCapacity(capacity);
setRemaining(remaining);
setBlockPoolUsed(blockPoolUsed);
setDfsUsed(dfsUsed);
setXceiverCount(xceiverCount);
setLastUpdate(Time.now());
this.volumeFailures = volFailures;
this.heartbeatedSinceFailover = true;
rollBlocksScheduled(getLastUpdate());
}
/**
* Iterates over the list of blocks belonging to the datanode.
*/
public static class BlockIterator implements Iterator<BlockInfo> {
private BlockInfo current;
private DatanodeDescriptor node;
BlockIterator(BlockInfo head, DatanodeDescriptor dn) {
this.current = head;
this.node = dn;
}
@Override
public boolean hasNext() {
return current != null;
}
@Override
public BlockInfo next() {
BlockInfo res = current;
current = current.getNext(current.findDatanode(node));
return res;
}
@Override
public void remove() {
throw new UnsupportedOperationException("Sorry. can't remove.");
}
}
public Iterator<BlockInfo> getBlockIterator() {
return new BlockIterator(this.blockList, this);
}
/**
* Store block replication work.
*/
void addBlockToBeReplicated(Block block, DatanodeDescriptor[] 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;
}
/**
* Increments counter for number of blocks scheduled.
*/
public void incBlocksScheduled() {
currApproxBlocksScheduled++;
}
/**
* Decrements counter for number of blocks scheduled.
*/
void decBlocksScheduled() {
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);
firstBlockReport = true; // must re-process IBR after re-registration
}
/**
* @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;
}
public boolean areBlockContentsStale() {
return blockContentsStale;
}
public void markStaleAfterFailover() {
heartbeatedSinceFailover = false;
blockContentsStale = true;
}
public void receivedBlockReport() {
if (heartbeatedSinceFailover) {
blockContentsStale = false;
}
firstBlockReport = false;
}
boolean isFirstBlockReport() {
return firstBlockReport;
}
@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();
}
}