HDFS-11799. Introduce a config to allow setting up write pipeline with fewer nodes than replication factor. Contributed by Brahma Reddy Battula
This commit is contained in:
Brahma Reddy Battula
parent
31b58406ac
commit
fda1221c55
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@ -223,6 +223,7 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory,
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final String clientName;
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final SocketFactory socketFactory;
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final ReplaceDatanodeOnFailure dtpReplaceDatanodeOnFailure;
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final short dtpReplaceDatanodeOnFailureReplication;
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private final FileSystem.Statistics stats;
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private final URI namenodeUri;
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private final Random r = new Random();
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@ -305,7 +306,17 @@ public DFSClient(URI nameNodeUri, ClientProtocol rpcNamenode,
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this.socketFactory = NetUtils.getSocketFactory(conf, ClientProtocol.class);
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this.dtpReplaceDatanodeOnFailure = ReplaceDatanodeOnFailure.get(conf);
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this.smallBufferSize = DFSUtilClient.getSmallBufferSize(conf);
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this.dtpReplaceDatanodeOnFailureReplication = (short) conf
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.getInt(HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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MIN_REPLICATION,
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HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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MIN_REPLICATION_DEFAULT);
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if (LOG.isDebugEnabled()) {
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LOG.debug(
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"Sets " + HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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MIN_REPLICATION + " to "
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+ dtpReplaceDatanodeOnFailureReplication);
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}
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this.ugi = UserGroupInformation.getCurrentUser();
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this.namenodeUri = nameNodeUri;
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@ -1384,7 +1384,36 @@ private void addDatanode2ExistingPipeline() throws IOException {
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setPipeline(lb);
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//find the new datanode
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final int d = findNewDatanode(original);
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final int d;
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try {
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d = findNewDatanode(original);
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} catch (IOException ioe) {
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// check the minimal number of nodes available to decide whether to
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// continue the write.
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//if live block location datanodes is greater than or equal to
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// HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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// MIN_REPLICATION threshold value, continue writing to the
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// remaining nodes. Otherwise throw exception.
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//
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// If HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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// MIN_REPLICATION is set to 0 or less than zero, an exception will be
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// thrown if a replacement could not be found.
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if (dfsClient.dtpReplaceDatanodeOnFailureReplication > 0 && nodes.length
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>= dfsClient.dtpReplaceDatanodeOnFailureReplication) {
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DFSClient.LOG.warn(
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"Failed to find a new datanode to add to the write pipeline, "
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+ " continue to write to the pipeline with " + nodes.length
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+ " nodes since it's no less than minimum replication: "
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+ dfsClient.dtpReplaceDatanodeOnFailureReplication
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+ " configured by "
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+ BlockWrite.ReplaceDatanodeOnFailure.MIN_REPLICATION
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+ ".", ioe);
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return;
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}
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throw ioe;
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}
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//transfer replica. pick a source from the original nodes
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final DatanodeInfo src = original[tried % original.length];
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final DatanodeInfo[] targets = {nodes[d]};
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@ -320,6 +320,8 @@ interface ReplaceDatanodeOnFailure {
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String POLICY_DEFAULT = "DEFAULT";
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String BEST_EFFORT_KEY = PREFIX + "best-effort";
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boolean BEST_EFFORT_DEFAULT = false;
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String MIN_REPLICATION = PREFIX + "min-replication";
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short MIN_REPLICATION_DEFAULT = 0;
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}
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}
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@ -658,6 +658,23 @@
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</description>
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</property>
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<property>
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<name>dfs.client.block.write.replace-datanode-on-failure.min-replication</name>
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<value>0</value>
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<description>
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The minimum number of replications that are needed to not to fail
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the write pipeline if new datanodes can not be found to replace
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failed datanodes (could be due to network failure) in the write pipeline.
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If the number of the remaining datanodes in the write pipeline is greater
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than or equal to this property value, continue writing to the remaining nodes.
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Otherwise throw exception.
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If this is set to 0, an exception will be thrown, when a replacement
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can not be found.
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See also dfs.client.block.write.replace-datanode-on-failure.policy
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</description>
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</property>
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<property>
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<name>dfs.blockreport.intervalMsec</name>
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<value>21600000</value>
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@ -0,0 +1,291 @@
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/**
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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* <p>
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* http://www.apache.org/licenses/LICENSE-2.0
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* <p>
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.hadoop.hdfs;
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.concurrent.TimeoutException;
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import org.apache.commons.logging.Log;
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import org.apache.commons.logging.LogFactory;
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import org.apache.hadoop.conf.Configuration;
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import org.apache.hadoop.fs.FSDataInputStream;
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import org.apache.hadoop.fs.Path;
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import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
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import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
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import org.apache.hadoop.hdfs.protocol.datatransfer.ReplaceDatanodeOnFailure;
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import org.apache.hadoop.hdfs.protocol.datatransfer.ReplaceDatanodeOnFailure.Policy;
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import org.apache.hadoop.io.IOUtils;
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import org.junit.Assert;
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import org.junit.Test;
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/**
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* Verify the behaviours of HdfsClientConfigKeys.BlockWrite.
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* ReplaceDatanodeOnFailure.MIN_REPLICATION.if live block location datanodes is
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* greater than or equal to
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* 'dfs.client.block.write.replace-datanode-on-failure.min.replication'
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* threshold value, if yes continue writing to the two remaining nodes.
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* Otherwise it will throw exception.
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* <p>
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* If this HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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* MIN_REPLICATION is set to 0 or less than zero, an exception will be thrown
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* if a replacement could not be found.
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*/
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public class TestReplaceDatanodeFailureReplication {
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static final Log LOG = LogFactory
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.getLog(TestReplaceDatanodeFailureReplication.class);
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static final String DIR =
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"/" + TestReplaceDatanodeFailureReplication.class.getSimpleName() + "/";
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static final short REPLICATION = 3;
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final private static String RACK0 = "/rack0";
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/**
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* Test fail last datanode in the pipeline.
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*/
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@Test
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public void testLastDatanodeFailureInPipeline() throws Exception {
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testWriteFileAndVerifyAfterDNStop(2, 1, 10, false);
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}
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/**
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* Test fail first datanode in the pipeline.
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*/
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@Test
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public void testFirstDatanodeFailureInPipeline() throws Exception {
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testWriteFileAndVerifyAfterDNStop(2, 0, 10, false);
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}
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/**
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* Test fail all the datanodes except first in the pipeline.
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*/
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@Test
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public void testWithOnlyFirstDatanodeIsAlive() throws Exception {
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testWriteFileAndVerifyAfterDNStop(1, 1, 1, true);
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}
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/**
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* Test fail all the datanodes except lastnode in the pipeline.
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*/
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@Test
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public void testWithOnlyLastDatanodeIsAlive() throws Exception {
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testWriteFileAndVerifyAfterDNStop(1, 0, 1, true);
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}
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/**
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* Test when number of live nodes are less than the
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* "dfs.client.block.write.replace-datanode-on-failure.min.replication".
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*/
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@Test
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public void testLessNumberOfLiveDatanodesThanWriteReplaceDatanodeOnFailureRF()
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throws Exception {
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final MiniDFSCluster cluster = setupCluster(2);
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try {
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final DistributedFileSystem fs = cluster.getFileSystem();
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final Path dir = new Path(DIR);
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final SlowWriter[] slowwriters = new SlowWriter[1];
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for (int i = 1; i <= slowwriters.length; i++) {
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// create slow writers in different speed
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slowwriters[i - 1] = new SlowWriter(fs, new Path(dir, "file" + i),
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i * 200L);
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}
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for (SlowWriter s : slowwriters) {
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s.start();
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}
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// Let slow writers write something.
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// Some of them are too slow and will be not yet started.
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sleepSeconds(1);
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// stop an old datanode
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cluster.stopDataNode(0);
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cluster.stopDataNode(0);
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// Let the slow writer writes a few more seconds
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// Everyone should have written something.
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sleepSeconds(20);
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// check replication and interrupt.
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for (SlowWriter s : slowwriters) {
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try {
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s.out.getCurrentBlockReplication();
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Assert.fail(
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"Must throw exception as failed to add a new datanode for write "
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+ "pipeline, minimum failure replication");
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} catch (IOException e) {
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// expected
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}
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s.interruptRunning();
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}
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// close files
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for (SlowWriter s : slowwriters) {
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s.joinAndClose();
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}
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// Verify the file
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verifyFileContent(fs, slowwriters);
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} finally {
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if (cluster != null) {
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cluster.shutdown();
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}
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}
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}
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private MiniDFSCluster setupCluster(int failRF) throws IOException {
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final Configuration conf = new HdfsConfiguration();
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conf.setInt(HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.
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MIN_REPLICATION, failRF);
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// always replace a datanode
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ReplaceDatanodeOnFailure.write(Policy.ALWAYS, false, conf);
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final String[] racks = new String[REPLICATION];
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Arrays.fill(racks, RACK0);
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return new MiniDFSCluster.Builder(conf).racks(racks)
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.numDataNodes(REPLICATION).build();
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}
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private void testWriteFileAndVerifyAfterDNStop(int failRF, int dnindex,
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int slowWrites, boolean failPipeLine)
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throws IOException, InterruptedException, TimeoutException {
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final MiniDFSCluster cluster = setupCluster(failRF);
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try {
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final DistributedFileSystem fs = cluster.getFileSystem();
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final Path dir = new Path(DIR);
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final SlowWriter[] slowwriters = new SlowWriter[slowWrites];
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for (int i = 1; i <= slowwriters.length; i++) {
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// create slow writers in different speed
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slowwriters[i - 1] = new SlowWriter(fs, new Path(dir, "file" + i),
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i * 200L);
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}
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for (SlowWriter s : slowwriters) {
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s.start();
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}
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// Let slow writers write something.
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// Some of them are too slow and will be not yet started.
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sleepSeconds(3);
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// stop an datanode
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cluster.stopDataNode(dnindex);
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if (failPipeLine) {
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cluster.stopDataNode(dnindex);
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}
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// Let the slow writer writes a few more seconds
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// Everyone should have written something.
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sleepSeconds(5);
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cluster.waitFirstBRCompleted(0, 10000);
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// check replication and interrupt.
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for (SlowWriter s : slowwriters) {
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Assert.assertEquals(failRF, s.out.getCurrentBlockReplication());
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s.interruptRunning();
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}
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// close files
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for (SlowWriter s : slowwriters) {
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s.joinAndClose();
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}
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// Verify the file
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verifyFileContent(fs, slowwriters);
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} finally {
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if (cluster != null) {
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cluster.shutdown();
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}
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}
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}
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private void verifyFileContent(DistributedFileSystem fs,
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SlowWriter[] slowwriters) throws IOException {
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LOG.info("Verify the file");
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for (int i = 0; i < slowwriters.length; i++) {
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LOG.info(slowwriters[i].filepath + ": length=" + fs
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.getFileStatus(slowwriters[i].filepath).getLen());
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FSDataInputStream in = null;
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try {
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in = fs.open(slowwriters[i].filepath);
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for (int j = 0, x;; j++) {
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x = in.read();
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if ((x) != -1) {
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Assert.assertEquals(j, x);
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} else {
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return;
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}
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}
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} finally {
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IOUtils.closeStream(in);
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}
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}
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}
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static void sleepSeconds(final int waittime) throws InterruptedException {
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LOG.info("Wait " + waittime + " seconds");
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Thread.sleep(waittime * 1000L);
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}
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static class SlowWriter extends Thread {
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private final Path filepath;
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private final HdfsDataOutputStream out;
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private final long sleepms;
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private volatile boolean running = true;
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SlowWriter(DistributedFileSystem fs, Path filepath, final long sleepms)
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throws IOException {
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super(SlowWriter.class.getSimpleName() + ":" + filepath);
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this.filepath = filepath;
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this.out = (HdfsDataOutputStream) fs.create(filepath, REPLICATION);
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this.sleepms = sleepms;
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}
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@Override public void run() {
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int i = 0;
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try {
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sleep(sleepms);
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for (; running; i++) {
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LOG.info(getName() + " writes " + i);
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out.write(i);
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out.hflush();
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sleep(sleepms);
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}
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} catch (InterruptedException e) {
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LOG.info(getName() + " interrupted:" + e);
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} catch (IOException e) {
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throw new RuntimeException(getName(), e);
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} finally {
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LOG.info(getName() + " terminated: i=" + i);
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}
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}
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void interruptRunning() {
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running = false;
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interrupt();
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}
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void joinAndClose() throws InterruptedException {
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LOG.info(getName() + " join and close");
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join();
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IOUtils.closeStream(out);
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}
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}
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}
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@ -41,8 +41,8 @@ public class TestHdfsConfigFields extends TestConfigurationFieldsBase {
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public void initializeMemberVariables() {
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xmlFilename = new String("hdfs-default.xml");
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configurationClasses = new Class[] { HdfsClientConfigKeys.class,
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HdfsClientConfigKeys.StripedRead.class,
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DFSConfigKeys.class};
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HdfsClientConfigKeys.StripedRead.class, DFSConfigKeys.class,
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HdfsClientConfigKeys.BlockWrite.ReplaceDatanodeOnFailure.class };
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// Set error modes
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errorIfMissingConfigProps = true;
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