/**
* 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.net;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* The class extends NetworkTopology to represents a cluster of computer with
* a 4-layers hierarchical network topology.
* In this network topology, leaves represent data nodes (computers) and inner
* nodes represent switches/routers that manage traffic in/out of data centers,
* racks or physical host (with virtual switch).
*
* @see NetworkTopology
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Unstable
public class NetworkTopologyWithNodeGroup extends NetworkTopology {
public final static String DEFAULT_NODEGROUP = "/default-nodegroup";
public NetworkTopologyWithNodeGroup() {
clusterMap = new InnerNodeWithNodeGroup(InnerNode.ROOT);
}
@Override
protected Node getNodeForNetworkLocation(Node node) {
// if node only with default rack info, here we need to add default
// nodegroup info
if (NetworkTopology.DEFAULT_RACK.equals(node.getNetworkLocation())) {
node.setNetworkLocation(node.getNetworkLocation()
+ DEFAULT_NODEGROUP);
}
Node nodeGroup = getNode(node.getNetworkLocation());
if (nodeGroup == null) {
nodeGroup = new InnerNodeWithNodeGroup(node.getNetworkLocation());
}
return getNode(nodeGroup.getNetworkLocation());
}
@Override
public String getRack(String loc) {
netlock.readLock().lock();
try {
loc = InnerNode.normalize(loc);
Node locNode = getNode(loc);
if (locNode instanceof InnerNodeWithNodeGroup) {
InnerNodeWithNodeGroup node = (InnerNodeWithNodeGroup) locNode;
if (node.isRack()) {
return loc;
} else if (node.isNodeGroup()) {
return node.getNetworkLocation();
} else {
// may be a data center
return null;
}
} else {
// not in cluster map, don't handle it
return loc;
}
} finally {
netlock.readLock().unlock();
}
}
/**
* Given a string representation of a node group for a specific network
* location
*
* @param loc
* a path-like string representation of a network location
* @return a node group string
*/
public String getNodeGroup(String loc) {
netlock.readLock().lock();
try {
loc = InnerNode.normalize(loc);
Node locNode = getNode(loc);
if (locNode instanceof InnerNodeWithNodeGroup) {
InnerNodeWithNodeGroup node = (InnerNodeWithNodeGroup) locNode;
if (node.isNodeGroup()) {
return loc;
} else if (node.isRack()) {
// not sure the node group for a rack
return null;
} else {
// may be a leaf node
if(!(node.getNetworkLocation() == null ||
node.getNetworkLocation().isEmpty())) {
return getNodeGroup(node.getNetworkLocation());
} else {
return NodeBase.ROOT;
}
}
} else {
// not in cluster map, don't handle it
return loc;
}
} finally {
netlock.readLock().unlock();
}
}
@Override
public boolean isOnSameRack( Node node1, Node node2) {
if (node1 == null || node2 == null ||
node1.getParent() == null || node2.getParent() == null) {
return false;
}
netlock.readLock().lock();
try {
return isSameParents(node1.getParent(), node2.getParent());
} finally {
netlock.readLock().unlock();
}
}
/**
* Check if two nodes are on the same node group (hypervisor) The
* assumption here is: each nodes are leaf nodes.
*
* @param node1
* one node (can be null)
* @param node2
* another node (can be null)
* @return true if node1 and node2 are on the same node group; false
* otherwise
* @exception IllegalArgumentException
* when either node1 or node2 is null, or node1 or node2 do
* not belong to the cluster
*/
@Override
public boolean isOnSameNodeGroup(Node node1, Node node2) {
if (node1 == null || node2 == null) {
return false;
}
netlock.readLock().lock();
try {
return isSameParents(node1, node2);
} finally {
netlock.readLock().unlock();
}
}
/**
* Check if network topology is aware of NodeGroup
*/
@Override
public boolean isNodeGroupAware() {
return true;
}
/** Add a leaf node
* Update node counter & rack counter if necessary
* @param node node to be added; can be null
* @exception IllegalArgumentException if add a node to a leave
* or node to be added is not a leaf
*/
@Override
public void add(Node node) {
if (node==null) return;
if( node instanceof InnerNode ) {
throw new IllegalArgumentException(
"Not allow to add an inner node: "+NodeBase.getPath(node));
}
netlock.writeLock().lock();
try {
Node rack = null;
// if node only with default rack info, here we need to add default
// nodegroup info
if (NetworkTopology.DEFAULT_RACK.equals(node.getNetworkLocation())) {
node.setNetworkLocation(node.getNetworkLocation() +
NetworkTopologyWithNodeGroup.DEFAULT_NODEGROUP);
}
Node nodeGroup = getNode(node.getNetworkLocation());
if (nodeGroup == null) {
nodeGroup = new InnerNodeWithNodeGroup(node.getNetworkLocation());
}
rack = getNode(nodeGroup.getNetworkLocation());
// rack should be an innerNode and with parent.
// note: rack's null parent case is: node's topology only has one layer,
// so rack is recognized as "/" and no parent.
// This will be recognized as a node with fault topology.
if (rack != null &&
(!(rack instanceof InnerNode) || rack.getParent() == null)) {
throw new IllegalArgumentException("Unexpected data node "
+ node.toString()
+ " at an illegal network location");
}
if (clusterMap.add(node)) {
LOG.info("Adding a new node: " + NodeBase.getPath(node));
if (rack == null) {
// We only track rack number here
incrementRacks();
}
}
if(LOG.isDebugEnabled()) {
LOG.debug("NetworkTopology became:\n" + this.toString());
}
} finally {
netlock.writeLock().unlock();
}
}
/** Remove a node
* Update node counter and rack counter if necessary
* @param node node to be removed; can be null
*/
@Override
public void remove(Node node) {
if (node==null) return;
if( node instanceof InnerNode ) {
throw new IllegalArgumentException(
"Not allow to remove an inner node: "+NodeBase.getPath(node));
}
LOG.info("Removing a node: "+NodeBase.getPath(node));
netlock.writeLock().lock();
try {
if (clusterMap.remove(node)) {
Node nodeGroup = getNode(node.getNetworkLocation());
if (nodeGroup == null) {
nodeGroup = new InnerNode(node.getNetworkLocation());
}
InnerNode rack = (InnerNode)getNode(nodeGroup.getNetworkLocation());
if (rack == null) {
numOfRacks--;
}
}
if(LOG.isDebugEnabled()) {
LOG.debug("NetworkTopology became:\n" + this.toString());
}
} finally {
netlock.writeLock().unlock();
}
}
@Override
protected int getWeight(Node reader, Node node) {
// 0 is local, 1 is same node group, 2 is same rack, 3 is off rack
// Start off by initializing to off rack
int weight = 3;
if (reader != null) {
if (reader.equals(node)) {
weight = 0;
} else if (isOnSameNodeGroup(reader, node)) {
weight = 1;
} else if (isOnSameRack(reader, node)) {
weight = 2;
}
}
return weight;
}
/**
* Sort nodes array by their distances to <i>reader</i>.
* <p/>
* This is the same as {@link NetworkTopology#sortByDistance(Node, Node[],
* int)} except with a four-level network topology which contains the
* additional network distance of a "node group" which is between local and
* same rack.
*
* @param reader Node where data will be read
* @param nodes Available replicas with the requested data
* @param activeLen Number of active nodes at the front of the array
*/
@Override
public void sortByDistance(Node reader, Node[] nodes, int activeLen) {
// If reader is not a datanode (not in NetworkTopology tree), we need to
// replace this reader with a sibling leaf node in tree.
if (reader != null && !this.contains(reader)) {
Node nodeGroup = getNode(reader.getNetworkLocation());
if (nodeGroup != null && nodeGroup instanceof InnerNode) {
InnerNode parentNode = (InnerNode) nodeGroup;
// replace reader with the first children of its parent in tree
reader = parentNode.getLeaf(0, null);
} else {
return;
}
}
super.sortByDistance(reader, nodes, activeLen);
}
/** InnerNodeWithNodeGroup represents a switch/router of a data center, rack
* or physical host. Different from a leaf node, it has non-null children.
*/
static class InnerNodeWithNodeGroup extends InnerNode {
public InnerNodeWithNodeGroup(String name, String location,
InnerNode parent, int level) {
super(name, location, parent, level);
}
public InnerNodeWithNodeGroup(String name, String location) {
super(name, location);
}
public InnerNodeWithNodeGroup(String path) {
super(path);
}
@Override
boolean isRack() {
// it is node group
if (getChildren().isEmpty()) {
return false;
}
Node firstChild = children.get(0);
if (firstChild instanceof InnerNode) {
Node firstGrandChild = (((InnerNode) firstChild).children).get(0);
if (firstGrandChild instanceof InnerNode) {
// it is datacenter
return false;
} else {
return true;
}
}
return false;
}
/**
* Judge if this node represents a node group
*
* @return true if it has no child or its children are not InnerNodes
*/
boolean isNodeGroup() {
if (children.isEmpty()) {
return true;
}
Node firstChild = children.get(0);
if (firstChild instanceof InnerNode) {
// it is rack or datacenter
return false;
}
return true;
}
@Override
protected boolean isLeafParent() {
return isNodeGroup();
}
@Override
protected InnerNode createParentNode(String parentName) {
return new InnerNodeWithNodeGroup(parentName, getPath(this), this,
this.getLevel() + 1);
}
@Override
protected boolean areChildrenLeaves() {
return isNodeGroup();
}
}
}