/**
* 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.datanode;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assume.assumeTrue;
import java.io.File;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.impl.Log4JLogger;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSTestUtil;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.util.DiskChecker;
import org.apache.hadoop.util.DiskChecker.DiskErrorException;
import org.apache.log4j.Level;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
/**
* Test the ability of a DN to tolerate volume failures.
*/
public class TestDataNodeVolumeFailureToleration {
private static final Log LOG = LogFactory.getLog(TestDataNodeVolumeFailureToleration.class);
{
((Log4JLogger)TestDataNodeVolumeFailureToleration.LOG).getLogger().setLevel(Level.ALL);
}
private FileSystem fs;
private MiniDFSCluster cluster;
private Configuration conf;
private String dataDir;
private int dirId;
@Before
public void setUp() throws Exception {
conf = new Configuration();
conf.setLong("dfs.block.size", 512);
conf.setInt("dfs.datanode.failed.volumes.tolerated", 1);
/*
* Lower the DN heartbeat, DF rate, and recheck interval to one second
* so state about failures and datanode death propagates faster.
*/
conf.setInt("dfs.heartbeat.interval", 1);
conf.setInt("dfs.df.interval", 1000);
conf.setInt("heartbeat.recheck.interval", 1000);
cluster = new MiniDFSCluster(conf, 1, true, null);
cluster.waitActive();
fs = cluster.getFileSystem();
dataDir = cluster.getDataDirectory();
}
@After
public void tearDown() throws Exception {
if (cluster != null)
cluster.shutdown();
}
/**
* Test the dfs.datanode.failed.volumes.tolerated configuration
* option, ie the DN tolerates a failed-to-use scenario during
* its start-up.
*/
@Test
public void testValidVolumesAtStartup() throws Exception {
assumeTrue(!System.getProperty("os.name").startsWith("Windows"));
// Make sure no DNs are running.
cluster.shutdownDataNodes();
File dataDir1 = new File(cluster.getBaseDataDir(), "data1");
dataDir1.mkdirs();
File dataDir2 = new File(cluster.getBaseDataDir(), "data2");
dataDir2.mkdirs();
try {
// Bring up a datanode with two default data dirs, but with one bad one.
assertEquals("Couldn't chmod local vol", 0,
FileUtil.chmod(dataDir1.toString(), "000"));
conf.setInt("dfs.datanode.failed.volumes.tolerated", 1);
// Start DN with manually managed DN dir
String dfsDir = dataDir2.getPath() + "," + dataDir1.getPath();
conf.set("dfs.data.dir", dfsDir);
cluster.startDataNodes(conf, 1, false, null, null);
cluster.waitActive();
assertTrue("The DN should have started up fine.",
cluster.isDataNodeUp());
DataNode dn = cluster.getDataNodes().get(0);
String si = dn.getFSDataset().getStorageInfo();
assertFalse("The DN shouldn't have a bad directory.",
si.contains(dataDir1.getPath()));
assertTrue("The DN should have started with this directory",
si.contains(dataDir2.getPath()));
} finally {
FileUtil.chmod(dataDir1.toString(), "755");
}
}
/**
* Test the dfs.datanode.failed.volumes.tolerated configuration
* option, ie the DN shuts itself down when the number of failures
* experienced drops below the tolerated amount.
*/
@Test
public void testConfigureMinValidVolumes() throws Exception {
assumeTrue(!System.getProperty("os.name").startsWith("Windows"));
// Bring up two additional datanodes that need both of their volumes
// functioning in order to stay up
conf.setInt("dfs.datanode.failed.volumes.tolerated", 0);
cluster.startDataNodes(conf, 2, true, null, null);
cluster.waitActive();
// Fail a volume on the 2nd DN
File dn2Vol1 = new File(new File(dataDir, "data"+(2*1+1)), "current");
try {
assertTrue("Couldn't chmod local vol", dn2Vol1.setExecutable(false));
// Should only get two replicas (the first DN and the 3rd)
Path file1 = new Path("/test1");
DFSTestUtil.createFile(fs, file1, 1024, (short)3, 1L);
DFSTestUtil.waitReplication(fs, file1, (short)2);
DFSTestUtil.waitNSecond(2);
assertFalse("2nd DN should be dead", cluster.getDataNodes().get(1).isDatanodeUp());
// If we restore the volume we should still only be able to get
// two replicas since the DN is still considered dead.
assertTrue("Couldn't chmod local vol", dn2Vol1.setExecutable(true));
Path file2 = new Path("/test2");
DFSTestUtil.createFile(fs, file2, 1024, (short)3, 1L);
DFSTestUtil.waitReplication(fs, file2, (short)2);
DFSTestUtil.waitNSecond(2);
assertFalse("2nd DN should be dead", cluster.getDataNodes().get(1).isDatanodeUp());
}
finally {
dn2Vol1.setExecutable(true);
}
}
/**
* Restart the datanodes with a new volume tolerated value.
* @param volTolerated number of dfs data dir failures to tolerate
* @param manageDfsDirs whether the mini cluster should manage data dirs
* @throws IOException
*/
private void restartDatanodes(int volTolerated, boolean manageDfsDirs)
throws IOException {
// Make sure no datanode is running
cluster.shutdownDataNodes();
conf.setInt("dfs.datanode.failed.volumes.tolerated", volTolerated);
cluster.startDataNodes(conf, 1, manageDfsDirs, null, null);
cluster.waitActive();
}
/**
* Test for different combination of volume configs and volumes tolerated
* values.
*/
@Test
public void testVolumeAndTolerableConfiguration() throws Exception {
dirId = 3;
// Check if Block Pool Service exit for an invalid conf value.
testVolumeConfig(-1, 0, false);
// Ditto if the value is too big.
testVolumeConfig(100, 0, false);
// Test for one failed volume with 1 tolerable volume
testVolumeConfig(1, 1, true);
// Test all good volumes
testVolumeConfig(0, 0, true);
// Test for one failed volume
testVolumeConfig(0, 1, false);
// Test all failed volumes
testVolumeConfig(0, 2, false);
}
/**
* Tests for a given volumes to be tolerated and volumes failed.
*/
private void testVolumeConfig(int volumesTolerated, int volumesFailed,
boolean expectedServiceState)
throws IOException, InterruptedException, TimeoutException {
assumeTrue(!System.getProperty("os.name").startsWith("Windows"));
File[] dirs = {
new File(dataDir, "data" + (dirId++)),
new File(dataDir, "data" + (dirId++))};
for (File dir: dirs) {
dir.mkdirs();
}
String dfsDir = dirs[0].getPath() + "," + dirs[1].getPath();
conf.set("dfs.data.dir", dfsDir);
try {
for (int i = 0; i < volumesFailed; i++) {
prepareDirToFail(dirs[i]);
}
try {
restartDatanodes(volumesTolerated, false);
}
catch (IOException e) {
LOG.error(e.toString());
}
if (expectedServiceState) {
assertTrue(cluster.isDataNodeUp() && cluster.getDataNodes().get(0).isDatanodeUp());
} else {
assertTrue(!cluster.isDataNodeUp() || !cluster.getDataNodes().get(0).isDatanodeUp());
}
} finally {
for (File dir : dirs) {
FileUtil.chmod(dir.toString(), "755");
}
}
}
/**
* Prepare directories for a failure, set dir permission to 000
* @param dir
* @throws IOException
* @throws InterruptedException
*/
private void prepareDirToFail(File dir) throws IOException,
InterruptedException {
dir.mkdirs();
assertEquals("Couldn't chmod local vol", 0,
FileUtil.chmod(dir.toString(), "000"));
}
}