diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/InnerNodeImpl.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/InnerNodeImpl.java index 81eaf7fdb4..5a2931bf6a 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/InnerNodeImpl.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/InnerNodeImpl.java @@ -63,7 +63,7 @@ int getNumOfChildren() { /** Judge if this node represents a rack * @return true if it has no child or its children are not InnerNodes */ - boolean isRack() { + public boolean isRack() { if (children.isEmpty()) { return true; } @@ -81,7 +81,7 @@ boolean isRack() { * @param n a node * @return true if this node is an ancestor of n */ - protected boolean isAncestor(Node n) { + public boolean isAncestor(Node n) { return getPath(this).equals(NodeBase.PATH_SEPARATOR_STR) || (n.getNetworkLocation()+NodeBase.PATH_SEPARATOR_STR). startsWith(getPath(this)+NodeBase.PATH_SEPARATOR_STR); @@ -92,12 +92,12 @@ protected boolean isAncestor(Node n) { * @param n a node * @return true if this node is the parent of n */ - protected boolean isParent(Node n) { + public boolean isParent(Node n) { return n.getNetworkLocation().equals(getPath(this)); } /* Return a child name of this node who is an ancestor of node n */ - protected String getNextAncestorName(Node n) { + public String getNextAncestorName(Node n) { if (!isAncestor(n)) { throw new IllegalArgumentException( this + "is not an ancestor of " + n); diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopologyWithNodeGroup.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopologyWithNodeGroup.java index a20d5fc855..bec0fe1306 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopologyWithNodeGroup.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/NetworkTopologyWithNodeGroup.java @@ -308,7 +308,7 @@ public InnerNodeWithNodeGroup(String path) { } @Override - boolean isRack() { + public boolean isRack() { // it is node group if (getChildren().isEmpty()) { return false; diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSNetworkTopology.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSNetworkTopology.java new file mode 100644 index 0000000000..ee83dba009 --- /dev/null +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSNetworkTopology.java @@ -0,0 +1,289 @@ +/** + * 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.net; + +import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Preconditions; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.StorageType; +import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor; +import org.apache.hadoop.net.NetworkTopology; +import org.apache.hadoop.net.Node; +import org.apache.hadoop.net.NodeBase; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.Random; + +/** + * The HDFS specific network topology class. The main purpose of doing this + * subclassing is to add storage-type-aware chooseRandom method. All the + * remaining parts should be the same. + * + * Currently a placeholder to test storage type info. + * TODO : add "chooseRandom with storageType info" function. + */ +public class DFSNetworkTopology extends NetworkTopology { + + private static final Random RANDOM = new Random(); + + public static DFSNetworkTopology getInstance(Configuration conf) { + DFSNetworkTopology nt = new DFSNetworkTopology(); + return (DFSNetworkTopology)nt.init(DFSTopologyNodeImpl.FACTORY); + } + + /** + * Randomly choose one node from scope, with specified storage type. + * + * If scope starts with ~, choose one from the all nodes except for the + * ones in scope; otherwise, choose one from scope. + * If excludedNodes is given, choose a node that's not in excludedNodes. + * + * @param scope range of nodes from which a node will be chosen + * @param excludedNodes nodes to be excluded from + * @return the chosen node + */ + public Node chooseRandomWithStorageType(final String scope, + final Collection excludedNodes, StorageType type) { + netlock.readLock().lock(); + try { + if (scope.startsWith("~")) { + return chooseRandomWithStorageType( + NodeBase.ROOT, scope.substring(1), excludedNodes, type); + } else { + return chooseRandomWithStorageType( + scope, null, excludedNodes, type); + } + } finally { + netlock.readLock().unlock(); + } + } + + /** + * Choose a random node based on given scope, excludedScope and excludedNodes + * set. Although in general the topology has at most three layers, this class + * will not impose such assumption. + * + * At high level, the idea is like this, say: + * + * R has two children A and B, and storage type is X, say: + * A has X = 6 (rooted at A there are 6 datanodes with X) and B has X = 8. + * + * Then R will generate a random int between 1~14, if it's <= 6, recursively + * call into A, otherwise B. This will maintain a uniformed randomness of + * choosing datanodes. + * + * The tricky part is how to handle excludes. + * + * For excludedNodes, since this set is small: currently the main reason of + * being an excluded node is because it already has a replica. So randomly + * picking up this node again should be rare. Thus we only check that, if the + * chosen node is excluded, we do chooseRandom again. + * + * For excludedScope, we locate the root of the excluded scope. Subtracting + * all it's ancestors' storage counters accordingly, this way the excluded + * root is out of the picture. + * + * TODO : this function has duplicate code as NetworkTopology, need to + * refactor in the future. + * + * @param scope + * @param excludedScope + * @param excludedNodes + * @return + */ + @VisibleForTesting + Node chooseRandomWithStorageType(final String scope, + String excludedScope, final Collection excludedNodes, + StorageType type) { + if (excludedScope != null) { + if (scope.startsWith(excludedScope)) { + return null; + } + if (!excludedScope.startsWith(scope)) { + excludedScope = null; + } + } + Node node = getNode(scope); + if (node == null) { + LOG.debug("Invalid scope {}, non-existing node", scope); + return null; + } + if (!(node instanceof DFSTopologyNodeImpl)) { + // a node is either DFSTopologyNodeImpl, or a DatanodeDescriptor + return ((DatanodeDescriptor)node).hasStorageType(type) ? node : null; + } + DFSTopologyNodeImpl root = (DFSTopologyNodeImpl)node; + Node excludeRoot = excludedScope == null ? null : getNode(excludedScope); + + // check to see if there are nodes satisfying the condition at all + int availableCount = root.getSubtreeStorageCount(type); + if (excludeRoot != null && root.isAncestor(excludeRoot)) { + if (excludeRoot instanceof DFSTopologyNodeImpl) { + availableCount -= ((DFSTopologyNodeImpl)excludeRoot) + .getSubtreeStorageCount(type); + } else { + availableCount -= ((DatanodeDescriptor)excludeRoot) + .hasStorageType(type) ? 1 : 0; + } + } + if (excludedNodes != null) { + for (Node excludedNode : excludedNodes) { + // all excluded nodes should be DatanodeDescriptor + Preconditions.checkArgument(excludedNode instanceof DatanodeDescriptor); + availableCount -= ((DatanodeDescriptor) excludedNode) + .hasStorageType(type) ? 1 : 0; + } + } + if (availableCount <= 0) { + // should never be <0 in general, adding <0 check for safety purpose + return null; + } + // to this point, it is guaranteed that there is at least one node + // that satisfies the requirement, keep trying until we found one. + Node chosen; + do { + chosen = chooseRandomWithStorageTypeAndExcludeRoot(root, excludeRoot, + type); + if (excludedNodes == null || !excludedNodes.contains(chosen)) { + break; + } else { + LOG.debug("Node {} is excluded, continuing.", chosen); + } + } while (true); + LOG.debug("chooseRandom returning {}", chosen); + return chosen; + } + + /** + * Choose a random node that has the required storage type, under the given + * root, with an excluded subtree root (could also just be a leaf node). + * + * Note that excludedNode is checked after a random node, so it is not being + * handled here. + * + * @param root the root node where we start searching for a datanode + * @param excludeRoot the root of the subtree what should be excluded + * @param type the expected storage type + * @return a random datanode, with the storage type, and is not in excluded + * scope + */ + private Node chooseRandomWithStorageTypeAndExcludeRoot( + DFSTopologyNodeImpl root, Node excludeRoot, StorageType type) { + Node chosenNode; + if (root.isRack()) { + // children are datanode descriptor + ArrayList candidates = new ArrayList<>(); + for (Node node : root.getChildren()) { + if (node.equals(excludeRoot)) { + continue; + } + DatanodeDescriptor dnDescriptor = (DatanodeDescriptor)node; + if (dnDescriptor.hasStorageType(type)) { + candidates.add(node); + } + } + if (candidates.size() == 0) { + return null; + } + // to this point, all nodes in candidates are valid choices, and they are + // all datanodes, pick a random one. + chosenNode = candidates.get(RANDOM.nextInt(candidates.size())); + } else { + // the children are inner nodes + ArrayList candidates = + getEligibleChildren(root, excludeRoot, type); + if (candidates.size() == 0) { + return null; + } + // again, all children are also inner nodes, we can do this cast. + // to maintain uniformality, the search needs to be based on the counts + // of valid datanodes. Below is a random weighted choose. + int totalCounts = 0; + int[] countArray = new int[candidates.size()]; + for (int i = 0; i < candidates.size(); i++) { + DFSTopologyNodeImpl innerNode = candidates.get(i); + int subTreeCount = innerNode.getSubtreeStorageCount(type); + totalCounts += subTreeCount; + countArray[i] = subTreeCount; + } + // generate a random val between [1, totalCounts] + int randomCounts = RANDOM.nextInt(totalCounts) + 1; + int idxChosen = 0; + // searching for the idxChosen can potentially be done with binary + // search, but does not seem to worth it here. + for (int i = 0; i < countArray.length; i++) { + if (randomCounts <= countArray[i]) { + idxChosen = i; + break; + } + randomCounts -= countArray[i]; + } + DFSTopologyNodeImpl nextRoot = candidates.get(idxChosen); + chosenNode = chooseRandomWithStorageTypeAndExcludeRoot( + nextRoot, excludeRoot, type); + } + return chosenNode; + } + + /** + * Given root, excluded root and storage type. Find all the children of the + * root, that has the storage type available. One check is that if the + * excluded root is under a children, this children must subtract the storage + * count of the excluded root. + * @param root the subtree root we check. + * @param excludeRoot the root of the subtree that should be excluded. + * @param type the storage type we look for. + * @return a list of possible nodes, each of them is eligible as the next + * level root we search. + */ + private ArrayList getEligibleChildren( + DFSTopologyNodeImpl root, Node excludeRoot, StorageType type) { + ArrayList candidates = new ArrayList<>(); + int excludeCount = 0; + if (excludeRoot != null && root.isAncestor(excludeRoot)) { + // the subtree to be excluded is under the given root, + // find out the number of nodes to be excluded. + if (excludeRoot instanceof DFSTopologyNodeImpl) { + // if excludedRoot is an inner node, get the counts of all nodes on + // this subtree of that storage type. + excludeCount = ((DFSTopologyNodeImpl) excludeRoot) + .getSubtreeStorageCount(type); + } else { + // if excludedRoot is a datanode, simply ignore this one node + if (((DatanodeDescriptor) excludeRoot).hasStorageType(type)) { + excludeCount = 1; + } + } + } + // have calculated the number of storage counts to be excluded. + // walk through all children to check eligibility. + for (Node node : root.getChildren()) { + DFSTopologyNodeImpl dfsNode = (DFSTopologyNodeImpl) node; + int storageCount = dfsNode.getSubtreeStorageCount(type); + if (excludeRoot != null && excludeCount != 0 && + (dfsNode.isAncestor(excludeRoot) || dfsNode.equals(excludeRoot))) { + storageCount -= excludeCount; + } + if (storageCount > 0) { + candidates.add(dfsNode); + } + } + return candidates; + } +} diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTopologyNodeImpl.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSTopologyNodeImpl.java similarity index 94% rename from hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTopologyNodeImpl.java rename to hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSTopologyNodeImpl.java index e746823a2e..92bb30395f 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTopologyNodeImpl.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/net/DFSTopologyNodeImpl.java @@ -15,7 +15,7 @@ * See the License for the specific language governing permissions and * limitations under the License. */ -package org.apache.hadoop.hdfs; +package org.apache.hadoop.hdfs.net; import com.google.common.annotations.VisibleForTesting; import org.apache.hadoop.fs.StorageType; @@ -27,6 +27,7 @@ import java.util.EnumMap; import java.util.EnumSet; import java.util.HashMap; +import java.util.Map; /** * The HDFS-specific representation of a network topology inner node. The @@ -86,6 +87,17 @@ public InnerNodeImpl newInnerNode(String path) { childrenStorageInfo = new HashMap<>(); } + public int getSubtreeStorageCount(StorageType type) { + int res = 0; + for (Map.Entry> entry : + childrenStorageInfo.entrySet()) { + if (entry.getValue().containsKey(type)) { + res += entry.getValue().get(type); + } + } + return res; + } + int getNumOfChildren() { return children.size(); } @@ -178,6 +190,16 @@ private DFSTopologyNodeImpl createParentNode(String parentName) { parentName, getPath(this), this, this.getLevel() + 1); } + @Override + public boolean equals(Object o) { + return super.equals(o); + } + + @Override + public int hashCode() { + return super.hashCode(); + } + @Override public boolean remove(Node n) { if (!isAncestor(n)) { diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java index 7b3e4e17d5..53d272aeca 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java @@ -941,5 +941,14 @@ public void setForceRegistration(boolean force) { public boolean isRegistered() { return isAlive() && !forceRegistration; } + + public boolean hasStorageType(StorageType type) { + for (DatanodeStorageInfo dnStorage : getStorageInfos()) { + if (dnStorage.getStorageType() == type) { + return true; + } + } + return false; + } } diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSNetworkTopology.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSNetworkTopology.java deleted file mode 100644 index a6b8c007ab..0000000000 --- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSNetworkTopology.java +++ /dev/null @@ -1,36 +0,0 @@ -/** - * 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; - -import org.apache.hadoop.conf.Configuration; -import org.apache.hadoop.net.NetworkTopology; - -/** - * The HDFS specific network topology class. The main purpose of doing this - * subclassing is to add storage-type-aware chooseRandom method. All the - * remaining parts should be the same. - * - * Currently a placeholder to test storage type info. - * TODO : add "chooseRandom with storageType info" function. - */ -public class DFSNetworkTopology extends NetworkTopology { - public static DFSNetworkTopology getInstance(Configuration conf) { - DFSNetworkTopology nt = new DFSNetworkTopology(); - return (DFSNetworkTopology)nt.init(DFSTopologyNodeImpl.FACTORY); - } -} diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSNetworkTopology.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/net/TestDFSNetworkTopology.java similarity index 60% rename from hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSNetworkTopology.java rename to hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/net/TestDFSNetworkTopology.java index ac1edf9e32..32ecf88670 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSNetworkTopology.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/net/TestDFSNetworkTopology.java @@ -15,14 +15,17 @@ * See the License for the specific language governing permissions and * limitations under the License. */ -package org.apache.hadoop.hdfs; +package org.apache.hadoop.hdfs.net; +import com.google.common.collect.Sets; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.StorageType; +import org.apache.hadoop.hdfs.DFSTestUtil; import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor; import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeStorageInfo; +import org.apache.hadoop.net.Node; import org.junit.Before; import org.junit.Rule; import org.junit.Test; @@ -30,6 +33,8 @@ import java.util.EnumMap; import java.util.HashMap; +import java.util.HashSet; +import java.util.Set; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertNull; @@ -62,9 +67,9 @@ public void setupDatanodes() { "/l2/d4/r1", "/l2/d4/r1"}; final String[] hosts = { "host1", "host2", "host3", "host4", "host5", - "host6", "host7", "host8", "host9", "host10", - "host11", "host12", "host13", "host14", "host15", - "host16", "host17", "host18", "host19", "host20"}; + "host6", "host7", "host8", + "host9", "host10", "host11", "host12", "host13", + "host14", "host15", "host16", "host17", "host18", "host19", "host20"}; final StorageType[] types = { StorageType.ARCHIVE, StorageType.DISK, StorageType.ARCHIVE, StorageType.DISK, StorageType.DISK, @@ -257,4 +262,188 @@ public void testAddAndRemoveTopology() throws Exception { assertNull(CLUSTER.getNode("/l1/d3")); } + + @Test + public void testChooseRandomWithStorageType() throws Exception { + Node n; + DatanodeDescriptor dd; + // test the choose random can return desired storage type nodes without + // exclude + Set diskUnderL1 = + Sets.newHashSet("host2", "host4", "host5", "host6"); + Set archiveUnderL1 = Sets.newHashSet("host1", "host3"); + Set ramdiskUnderL1 = Sets.newHashSet("host7"); + Set ssdUnderL1 = Sets.newHashSet("host8"); + for (int i = 0; i < 10; i++) { + n = CLUSTER.chooseRandomWithStorageType("/l1", null, null, + StorageType.DISK); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(diskUnderL1.contains(dd.getHostName())); + + n = CLUSTER.chooseRandomWithStorageType("/l1", null, null, + StorageType.RAM_DISK); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(ramdiskUnderL1.contains(dd.getHostName())); + + n = CLUSTER.chooseRandomWithStorageType("/l1", null, null, + StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(archiveUnderL1.contains(dd.getHostName())); + + n = CLUSTER.chooseRandomWithStorageType("/l1", null, null, + StorageType.SSD); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(ssdUnderL1.contains(dd.getHostName())); + } + } + + @Test + public void testChooseRandomWithStorageTypeWithExcluded() throws Exception { + Node n; + DatanodeDescriptor dd; + // below test choose random with exclude, for /l2/d3, every rack has exactly + // one host + // /l2/d3 has five racks r[1~5] but only r4 and r5 have ARCHIVE + // host12 is the one under "/l2/d3/r4", host13 is the one under "/l2/d3/r5" + n = CLUSTER.chooseRandomWithStorageType("/l2/d3/r4", null, null, + StorageType.ARCHIVE); + HashSet excluded = new HashSet<>(); + // exclude the host on r4 (since there is only one host, no randomness here) + excluded.add(n); + + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType("/l2/d3", null, null, + StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host12") || + dd.getHostName().equals("host13")); + } + + // test exclude nodes + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType("/l2/d3", null, excluded, + StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host13")); + } + + // test exclude scope + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType("/l2/d3", "/l2/d3/r4", null, + StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host13")); + } + + // test exclude scope + excluded node with expected null return node + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType("/l2/d3", "/l2/d3/r5", excluded, + StorageType.ARCHIVE); + assertNull(n); + } + + // test exclude scope + excluded node with expected non-null return node + n = CLUSTER.chooseRandomWithStorageType("/l1/d2", null, null, + StorageType.DISK); + dd = (DatanodeDescriptor)n; + assertEquals("host6", dd.getHostName()); + // exclude the host on r4 (since there is only one host, no randomness here) + excluded.add(n); + Set expectedSet = Sets.newHashSet("host4", "host5"); + for (int i = 0; i<10; i++) { + // under l1, there are four hosts with DISK: + // /l1/d1/r1/host2, /l1/d1/r2/host4, /l1/d1/r2/host5 and /l1/d2/r3/host6 + // host6 is excludedNode, host2 is under excluded range scope /l1/d1/r1 + // so should always return r4 or r5 + n = CLUSTER.chooseRandomWithStorageType( + "/l1", "/l1/d1/r1", excluded, StorageType.DISK); + dd = (DatanodeDescriptor) n; + assertTrue(expectedSet.contains(dd.getHostName())); + } + } + + + /** + * This test tests the wrapper method. The wrapper method only takes one scope + * where if it starts with a ~, it is an excluded scope, and searching always + * from root. Otherwise it is a scope. + * @throws Exception throws exception. + */ + @Test + public void testChooseRandomWithStorageTypeWrapper() throws Exception { + Node n; + DatanodeDescriptor dd; + n = CLUSTER.chooseRandomWithStorageType("/l2/d3/r4", null, null, + StorageType.ARCHIVE); + HashSet excluded = new HashSet<>(); + // exclude the host on r4 (since there is only one host, no randomness here) + excluded.add(n); + + // search with given scope being desired scope + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType( + "/l2/d3", null, StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host12") || + dd.getHostName().equals("host13")); + } + + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType( + "/l2/d3", excluded, StorageType.ARCHIVE); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host13")); + } + + // search with given scope being exclude scope + + // a total of 4 ramdisk nodes: + // /l1/d2/r3/host7, /l2/d3/r2/host10, /l2/d4/r1/host7 and /l2/d4/r1/host10 + // so if we exclude /l2/d4/r1, if should be always either host7 or host10 + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType( + "~/l2/d4", null, StorageType.RAM_DISK); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host7") || + dd.getHostName().equals("host10")); + } + + // similar to above, except that we also exclude host10 here. so it should + // always be host7 + n = CLUSTER.chooseRandomWithStorageType("/l2/d3/r2", null, null, + StorageType.RAM_DISK); + // add host10 to exclude + excluded.add(n); + for (int i = 0; i<10; i++) { + n = CLUSTER.chooseRandomWithStorageType( + "~/l2/d4", excluded, StorageType.RAM_DISK); + assertTrue(n instanceof DatanodeDescriptor); + dd = (DatanodeDescriptor) n; + assertTrue(dd.getHostName().equals("host7")); + } + } + + @Test + public void testNonExistingNode() throws Exception { + Node n; + n = CLUSTER.chooseRandomWithStorageType( + "/l100", null, null, StorageType.DISK); + assertNull(n); + n = CLUSTER.chooseRandomWithStorageType( + "/l100/d100", null, null, StorageType.DISK); + assertNull(n); + n = CLUSTER.chooseRandomWithStorageType( + "/l100/d100/r100", null, null, StorageType.DISK); + assertNull(n); + } }