/**
* 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 java.io.File;
import java.io.IOException;
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.hdfs.server.namenode.FSNamesystem;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.impl.Log4JLogger;
import org.apache.log4j.Level;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.*;
import static org.junit.Assume.assumeTrue;
/**
* 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;
// Sleep at least 3 seconds (a 1s heartbeat plus padding) to allow
// for heartbeats to propagate from the datanodes to the namenode.
final int WAIT_FOR_HEARTBEATS = 3000;
// Wait at least (2 * re-check + 10 * heartbeat) seconds for
// a datanode to be considered dead by the namenode.
final int WAIT_FOR_DEATH = 15000;
@Before
public void setUp() throws Exception {
conf = new Configuration();
conf.setLong("dfs.block.size", 512L);
/*
* Lower the DN heartbeat, DF rate, and recheck interval to one second
* so state about failures and datanode death propagates faster.
*/
conf.setInt(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1);
conf.setInt(DFSConfigKeys.DFS_DF_INTERVAL_KEY, 1000);
conf.setInt("heartbeat.recheck.interval", 1000);
// Allow a single volume failure (there are two volumes)
conf.setInt("dfs.datanode.failed.volumes.tolerated", 1);
cluster = new MiniDFSCluster(conf, 1, true, null);
cluster.waitActive();
fs = cluster.getFileSystem();
dataDir = cluster.getDataDirectory();
}
@After
public void tearDown() throws Exception {
for (int i = 0; i < 3; i++) {
new File(dataDir, "data"+(2*i+1)).setExecutable(true);
new File(dataDir, "data"+(2*i+2)).setExecutable(true);
}
cluster.shutdown();
}
/**
* Test the DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY 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();
FSNamesystem ns = cluster.getNameNode().getNamesystem();
long origCapacity = DFSTestUtil.getLiveDatanodeCapacity(ns);
long dnCapacity = DFSTestUtil.getDatanodeCapacity(ns, 0);
// Fail a volume on the 2nd DN
File dn2Vol1 = new File(dataDir, "data"+(2*1+1));
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);
// Check that this single failure caused a DN to die.
DFSTestUtil.waitForDatanodeStatus(ns, 2, 1, 0,
origCapacity - (1*dnCapacity), WAIT_FOR_HEARTBEATS);
// 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);
}
/**
* Restart the datanodes in the cluster with a new volume tolerated value.
* @param volTolerated
* @param manageDfsDirs
* @throws IOException
*/
private void restartDatanodes(int volTolerated, boolean manageDfsDirs)
throws IOException {
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 testInvalidFailedVolumesConfig() throws Exception {
assumeTrue(!System.getProperty("os.name").startsWith("Windows"));
// Check if DN exits for an invalid conf value.
testVolumeConfig(-1, 0, false, true);
testVolumeConfig(100, 0, false, true);
// Test for one failed volume
testVolumeConfig(0, 1, false, false);
// Test for one failed volume with 1 tolerable volume
testVolumeConfig(1, 1, true, false);
// Test all good volumes
testVolumeConfig(0, 0, true, false);
// Test all failed volumes
testVolumeConfig(0, 2, false, false);
}
/**
* Tests for a given volumes to be tolerated and volumes failed.
*/
private void testVolumeConfig(int volumesTolerated, int volumesFailed,
boolean expectDnUp, boolean manageDfsDirs)
throws IOException, InterruptedException {
File dir0 = new File(dataDir, "data1");
File dir1 = new File(dataDir, "data2");
// Fail the current directory since invalid storage directory perms
// get fixed up automatically on datanode startup.
File[] currDirs = { new File(dir0, "/current"),
new File(dir1, "/current") };
try {
for (int i = 0; i < volumesFailed; i++) {
prepareDirToFail(currDirs[i]);
}
try {
restartDatanodes(volumesTolerated, manageDfsDirs);
assertEquals(expectDnUp, cluster.getDataNodes().get(0).isDatanodeUp());
} catch (IOException ioe) {
assertFalse("Expected successful restart but got " + ioe, expectDnUp);
}
} finally {
for (File dir : currDirs) {
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"));
}
/**
* Test that a volume that is considered failed on startup is seen as
* a failed volume by the NN.
*/
@Test
public void testFailedVolumeOnStartupIsCounted() throws Exception {
assumeTrue(!System.getProperty("os.name").startsWith("Windows"));
FSNamesystem ns = cluster.getNameNode().getNamesystem();
long origCapacity = DFSTestUtil.getLiveDatanodeCapacity(ns);
File dir = new File(dataDir, "data1/current");
try {
prepareDirToFail(dir);
restartDatanodes(1, false);
// The cluster is up..
assertTrue(cluster.getDataNodes().get(0).isDatanodeUp());
// but there has been a single volume failure
DFSTestUtil.waitForDatanodeStatus(ns, 1, 0, 1,
origCapacity / 2, WAIT_FOR_HEARTBEATS);
} finally {
FileUtil.chmod(dir.toString(), "755");
}
}
}