/**
 * 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.namenode.metrics;

import java.util.concurrent.TimeUnit;
import org.apache.hadoop.crypto.key.JavaKeyStoreProvider;
import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
import org.apache.hadoop.fs.FileSystemTestHelper;
import org.apache.hadoop.fs.FileSystemTestWrapper;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.ha.HAServiceProtocol;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.StripedFileTestUtil;
import org.apache.hadoop.hdfs.client.CreateEncryptionZoneFlag;
import org.apache.hadoop.hdfs.client.HdfsAdmin;

import static org.apache.hadoop.fs.CommonConfigurationKeys.HA_HM_RPC_TIMEOUT_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeys.HA_HM_RPC_TIMEOUT_KEY;
import static org.apache.hadoop.test.MetricsAsserts.assertCounter;
import static org.apache.hadoop.test.MetricsAsserts.assertCounterGt;
import static org.apache.hadoop.test.MetricsAsserts.assertGauge;
import static org.apache.hadoop.test.MetricsAsserts.assertQuantileGauges;
import static org.apache.hadoop.test.MetricsAsserts.getMetrics;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.Random;
import com.google.common.collect.ImmutableList;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Options.Rename;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.DFSTestUtil;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.MiniDFSNNTopology;
import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
import org.apache.hadoop.hdfs.protocol.LocatedStripedBlock;
import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil;
import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
import org.apache.hadoop.hdfs.server.common.Storage;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
import org.apache.hadoop.hdfs.server.namenode.MockNameNodeResourceChecker;
import org.apache.hadoop.hdfs.server.namenode.NameNode;
import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.hadoop.hdfs.server.namenode.ha.HATestUtil;
import org.apache.hadoop.hdfs.tools.NNHAServiceTarget;
import org.apache.hadoop.hdfs.util.HostsFileWriter;
import org.apache.hadoop.metrics2.MetricsRecordBuilder;
import org.apache.hadoop.metrics2.MetricsSource;
import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
import org.apache.hadoop.test.GenericTestUtils;
import org.apache.hadoop.test.MetricsAsserts;
import org.apache.log4j.Level;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Test for metrics published by the Namenode
 */
public class TestNameNodeMetrics {
  private static final Configuration CONF = new HdfsConfiguration();
  private static final int DFS_REDUNDANCY_INTERVAL = 1;
  private static final Path TEST_ROOT_DIR_PATH = 
    new Path("/testNameNodeMetrics");
  private static final String NN_METRICS = "NameNodeActivity";
  private static final String NS_METRICS = "FSNamesystem";
  private static final int BLOCK_SIZE = 1024 * 1024;
  private static final ErasureCodingPolicy EC_POLICY =
      SystemErasureCodingPolicies.getByID(
          SystemErasureCodingPolicies.XOR_2_1_POLICY_ID);

  public static final Log LOG = LogFactory.getLog(TestNameNodeMetrics.class);
  
  // Number of datanodes in the cluster
  private static final int DATANODE_COUNT = EC_POLICY.getNumDataUnits() +
      EC_POLICY.getNumParityUnits() + 1;
  private static final int WAIT_GAUGE_VALUE_RETRIES = 20;
  
  // Rollover interval of percentile metrics (in seconds)
  private static final int PERCENTILES_INTERVAL = 1;

  static {
    CONF.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
    CONF.setInt(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_KEY, 1);
    CONF.setLong(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY,
        DFS_REDUNDANCY_INTERVAL);
    // Set it long enough to essentially disable unless we manually call it
    // Used for decommissioning DataNode metrics
    CONF.setTimeDuration(
        MiniDFSCluster.DFS_NAMENODE_DECOMMISSION_INTERVAL_TESTING_KEY, 999,
        TimeUnit.DAYS);
    // Next two configs used for checking failed volume metrics
    CONF.setTimeDuration(DFSConfigKeys.DFS_DATANODE_DISK_CHECK_MIN_GAP_KEY,
        10, TimeUnit.MILLISECONDS);
    CONF.setInt(DFSConfigKeys.DFS_DATANODE_FAILED_VOLUMES_TOLERATED_KEY, 1);
    CONF.setInt(DFSConfigKeys.DFS_NAMENODE_REDUNDANCY_INTERVAL_SECONDS_KEY,
        DFS_REDUNDANCY_INTERVAL);
    CONF.set(DFSConfigKeys.DFS_METRICS_PERCENTILES_INTERVALS_KEY, 
        "" + PERCENTILES_INTERVAL);
    // Enable stale DataNodes checking
    CONF.setBoolean(
        DFSConfigKeys.DFS_NAMENODE_AVOID_STALE_DATANODE_FOR_READ_KEY, true);
    GenericTestUtils.setLogLevel(LogFactory.getLog(MetricsAsserts.class),
        Level.DEBUG);
  }
  
  private MiniDFSCluster cluster;
  private DistributedFileSystem fs;
  private final Random rand = new Random();
  private FSNamesystem namesystem;
  private HostsFileWriter hostsFileWriter;
  private BlockManager bm;
  private Path ecDir;

  private static Path getTestPath(String fileName) {
    return new Path(TEST_ROOT_DIR_PATH, fileName);
  }

  @Before
  public void setUp() throws Exception {
    hostsFileWriter = new HostsFileWriter();
    hostsFileWriter.initialize(CONF, "temp/decommission");
    cluster = new MiniDFSCluster.Builder(CONF).numDataNodes(DATANODE_COUNT)
        .build();
    cluster.waitActive();
    namesystem = cluster.getNamesystem();
    bm = namesystem.getBlockManager();
    fs = cluster.getFileSystem();
    fs.enableErasureCodingPolicy(EC_POLICY.getName());
    ecDir = getTestPath("/ec");
    fs.mkdirs(ecDir);
    fs.setErasureCodingPolicy(ecDir, EC_POLICY.getName());
  }
  
  @After
  public void tearDown() throws Exception {
    MetricsSource source = DefaultMetricsSystem.instance().getSource("UgiMetrics");
    if (source != null) {
      // Run only once since the UGI metrics is cleaned up during teardown
      MetricsRecordBuilder rb = getMetrics(source);
      assertQuantileGauges("GetGroups1s", rb);
    }
    if (hostsFileWriter != null) {
      hostsFileWriter.cleanup();
      hostsFileWriter = null;
    }
    if (cluster != null) {
      cluster.shutdown();
      cluster = null;
    }
  }
  
  /** create a file with a length of <code>fileLen</code> */
  private void createFile(Path file, long fileLen, short replicas) throws IOException {
    DFSTestUtil.createFile(fs, file, fileLen, replicas, rand.nextLong());
  }

  private void readFile(FileSystem fileSys,Path name) throws IOException {
    //Just read file so that getNumBlockLocations are incremented
    DataInputStream stm = fileSys.open(name);
    byte [] buffer = new byte[4];
    stm.read(buffer,0,4);
    stm.close();
  }

  /**
   * Test that capacity metrics are exported and pass
   * basic sanity tests.
   */
  @Test (timeout = 10000)
  public void testCapacityMetrics() throws Exception {
    MetricsRecordBuilder rb = getMetrics(NS_METRICS);
    long capacityTotal = MetricsAsserts.getLongGauge("CapacityTotal", rb);
    assert(capacityTotal != 0);
    long capacityUsed = MetricsAsserts.getLongGauge("CapacityUsed", rb);
    long capacityRemaining =
        MetricsAsserts.getLongGauge("CapacityRemaining", rb);
    long capacityUsedNonDFS =
        MetricsAsserts.getLongGauge("CapacityUsedNonDFS", rb);
    // There will be 5% space reserved in ext filesystem which is not
    // considered.
    assert (capacityUsed + capacityRemaining + capacityUsedNonDFS <=
        capacityTotal);
  }

  /** Test metrics indicating the number of stale DataNodes */
  @Test
  public void testStaleNodes() throws Exception {
    // Set two datanodes as stale
    for (int i = 0; i < 2; i++) {
      DataNode dn = cluster.getDataNodes().get(i);
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, true);
      long staleInterval = CONF.getLong(
          DFSConfigKeys.DFS_NAMENODE_STALE_DATANODE_INTERVAL_KEY,
          DFSConfigKeys.DFS_NAMENODE_STALE_DATANODE_INTERVAL_DEFAULT);
      DatanodeDescriptor dnDes = cluster.getNameNode().getNamesystem()
          .getBlockManager().getDatanodeManager()
          .getDatanode(dn.getDatanodeId());
      DFSTestUtil.resetLastUpdatesWithOffset(dnDes, -(staleInterval + 1));
    }
    // Let HeartbeatManager to check heartbeat
    BlockManagerTestUtil.checkHeartbeat(cluster.getNameNode().getNamesystem()
        .getBlockManager());
    assertGauge("StaleDataNodes", 2, getMetrics(NS_METRICS));
    
    // Reset stale datanodes
    for (int i = 0; i < 2; i++) {
      DataNode dn = cluster.getDataNodes().get(i);
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, false);
      DatanodeDescriptor dnDes = cluster.getNameNode().getNamesystem()
          .getBlockManager().getDatanodeManager()
          .getDatanode(dn.getDatanodeId());
      DFSTestUtil.resetLastUpdatesWithOffset(dnDes, 0);
    }
    
    // Let HeartbeatManager to refresh
    BlockManagerTestUtil.checkHeartbeat(cluster.getNameNode().getNamesystem()
        .getBlockManager());
    assertGauge("StaleDataNodes", 0, getMetrics(NS_METRICS));
  }

  /**
   * Test metrics associated with volume failures.
   */
  @Test
  public void testVolumeFailures() throws Exception {
    assertGauge("VolumeFailuresTotal", 0, getMetrics(NS_METRICS));
    assertGauge("EstimatedCapacityLostTotal", 0L, getMetrics(NS_METRICS));
    DataNode dn = cluster.getDataNodes().get(0);
    FsDatasetSpi.FsVolumeReferences volumeReferences =
        DataNodeTestUtils.getFSDataset(dn).getFsVolumeReferences();
    FsVolumeImpl fsVolume = (FsVolumeImpl) volumeReferences.get(0);
    File dataDir = new File(fsVolume.getBaseURI());
    long capacity = fsVolume.getCapacity();
    volumeReferences.close();
    File storageDir = new File(dataDir, Storage.STORAGE_DIR_CURRENT);
    DataNodeTestUtils.injectDataDirFailure(storageDir);
    DataNodeTestUtils.waitForDiskError(dn, fsVolume);
    DataNodeTestUtils.triggerHeartbeat(dn);
    BlockManagerTestUtil.checkHeartbeat(bm);
    assertGauge("VolumeFailuresTotal", 1, getMetrics(NS_METRICS));
    assertGauge("EstimatedCapacityLostTotal", capacity, getMetrics(NS_METRICS));
  }

  /**
   * Test metrics associated with liveness and decommission status of DataNodes.
   */
  @Test
  public void testDataNodeLivenessAndDecom() throws Exception {
    List<DataNode> dataNodes = cluster.getDataNodes();
    DatanodeDescriptor[] dnDescriptors = new DatanodeDescriptor[DATANODE_COUNT];
    String[] dnAddresses = new String[DATANODE_COUNT];
    for (int i = 0; i < DATANODE_COUNT; i++) {
      dnDescriptors[i] = bm.getDatanodeManager()
          .getDatanode(dataNodes.get(i).getDatanodeId());
      dnAddresses[i] = dnDescriptors[i].getXferAddr();
    }
    // First put all DNs into include
    hostsFileWriter.initIncludeHosts(dnAddresses);
    bm.getDatanodeManager().refreshNodes(CONF);
    assertGauge("NumDecomLiveDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumLiveDataNodes", DATANODE_COUNT, getMetrics(NS_METRICS));

    // Now decommission one DN
    hostsFileWriter.initExcludeHost(dnAddresses[0]);
    bm.getDatanodeManager().refreshNodes(CONF);
    assertGauge("NumDecommissioningDataNodes", 1, getMetrics(NS_METRICS));
    BlockManagerTestUtil.recheckDecommissionState(bm.getDatanodeManager());
    assertGauge("NumDecommissioningDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumDecomLiveDataNodes", 1, getMetrics(NS_METRICS));
    assertGauge("NumLiveDataNodes", DATANODE_COUNT, getMetrics(NS_METRICS));

    // Now kill all DNs by expiring their heartbeats
    for (int i = 0; i < DATANODE_COUNT; i++) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dataNodes.get(i), true);
      long expireInterval = CONF.getLong(
          DFSConfigKeys.DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_KEY,
          DFSConfigKeys.DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_DEFAULT) * 2L
          + CONF.getLong(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY,
          DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_DEFAULT) * 10 * 1000L;
      DFSTestUtil.resetLastUpdatesWithOffset(dnDescriptors[i],
          -(expireInterval + 1));
    }
    BlockManagerTestUtil.checkHeartbeat(bm);
    assertGauge("NumDecomLiveDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumDecomDeadDataNodes", 1, getMetrics(NS_METRICS));
    assertGauge("NumLiveDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumDeadDataNodes", DATANODE_COUNT, getMetrics(NS_METRICS));

    // Now remove the decommissioned DN altogether
    String[] includeHosts = new String[dnAddresses.length - 1];
    for (int i = 0; i < includeHosts.length; i++) {
      includeHosts[i] = dnAddresses[i + 1];
    }
    hostsFileWriter.initIncludeHosts(includeHosts);
    hostsFileWriter.initExcludeHosts(new ArrayList<>());
    bm.getDatanodeManager().refreshNodes(CONF);
    assertGauge("NumDecomLiveDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumDecomDeadDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumLiveDataNodes", 0, getMetrics(NS_METRICS));
    assertGauge("NumDeadDataNodes", DATANODE_COUNT - 1, getMetrics(NS_METRICS));

    // Finally mark the remaining DNs as live again
    for (int i = 1; i < dataNodes.size(); i++) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dataNodes.get(i), false);
      DFSTestUtil.resetLastUpdatesWithOffset(dnDescriptors[i], 0);
    }
    BlockManagerTestUtil.checkHeartbeat(bm);
    assertGauge("NumLiveDataNodes", DATANODE_COUNT - 1, getMetrics(NS_METRICS));
    assertGauge("NumDeadDataNodes", 0, getMetrics(NS_METRICS));
  }
  
  /** Test metrics associated with addition of a file */
  @Test
  public void testFileAdd() throws Exception {
    // File creations
    final long blockCount = 32;
    final Path normalFile = getTestPath("testFileAdd");
    createFile(normalFile, blockCount * BLOCK_SIZE, (short)3);
    final Path ecFile = new Path(ecDir, "ecFile.log");
    DFSTestUtil.createStripedFile(cluster, ecFile, null, (int) blockCount, 1,
        false, EC_POLICY);

    int blockCapacity = namesystem.getBlockCapacity();
    assertGauge("BlockCapacity", blockCapacity, getMetrics(NS_METRICS));

    MetricsRecordBuilder rb = getMetrics(NN_METRICS);
    // File create operations are 2
    assertCounter("CreateFileOps", 2L, rb);
    // Number of files created is depth of normalFile and ecFile, after
    // removing the duplicate accounting for root test dir.
    assertCounter("FilesCreated",
        (long)(normalFile.depth() + ecFile.depth()), rb);

    long filesTotal = normalFile.depth() + ecFile.depth() + 1 /* ecDir */;
    rb = getMetrics(NS_METRICS);
    assertGauge("FilesTotal", filesTotal, rb);
    assertGauge("BlocksTotal", blockCount * 2, rb);
    fs.delete(normalFile, true);
    filesTotal--; // reduce the filecount for deleted file

    rb = waitForDnMetricValue(NS_METRICS, "FilesTotal", filesTotal);
    assertGauge("BlocksTotal", blockCount, rb);
    assertGauge("PendingDeletionBlocks", 0L, rb);

    fs.delete(ecFile, true);
    filesTotal--;
    rb = waitForDnMetricValue(NS_METRICS, "FilesTotal", filesTotal);
    assertGauge("BlocksTotal", 0L, rb);
    assertGauge("PendingDeletionBlocks", 0L, rb);

    rb = getMetrics(NN_METRICS);
    // Delete file operations and number of files deleted must be 1
    assertCounter("DeleteFileOps", 2L, rb);
    assertCounter("FilesDeleted", 2L, rb);
  }

  /**
   * Verify low redundancy and corrupt blocks metrics are zero.
   * @throws Exception
   */
  private void verifyZeroMetrics() throws Exception {
    BlockManagerTestUtil.updateState(bm);
    MetricsRecordBuilder rb = waitForDnMetricValue(NS_METRICS,
        "CorruptBlocks", 0L, 500);

    // Verify aggregated blocks metrics
    assertGauge("UnderReplicatedBlocks", 0L, rb); // Deprecated metric
    assertGauge("LowRedundancyBlocks", 0L, rb);
    assertGauge("PendingReplicationBlocks", 0L, rb); // Deprecated metric
    assertGauge("PendingReconstructionBlocks", 0L, rb);

    // Verify replica metrics
    assertGauge("LowRedundancyReplicatedBlocks", 0L, rb);
    assertGauge("CorruptReplicatedBlocks", 0L, rb);

    // Verify striped block groups metrics
    assertGauge("LowRedundancyECBlockGroups", 0L, rb);
    assertGauge("CorruptECBlockGroups", 0L, rb);
  }

  /**
   * Verify aggregated metrics equals the sum of replicated blocks metrics
   * and erasure coded blocks metrics.
   * @throws Exception
   */
  private void verifyAggregatedMetricsTally() throws Exception {
    BlockManagerTestUtil.updateState(bm);
    assertEquals("Under replicated metrics not matching!",
        namesystem.getLowRedundancyBlocks(),
        namesystem.getUnderReplicatedBlocks());
    assertEquals("Low redundancy metrics not matching!",
        namesystem.getLowRedundancyBlocks(),
        namesystem.getLowRedundancyReplicatedBlocks() +
            namesystem.getLowRedundancyECBlockGroups());
    assertEquals("Corrupt blocks metrics not matching!",
        namesystem.getCorruptReplicaBlocks(),
        namesystem.getCorruptReplicatedBlocks() +
            namesystem.getCorruptECBlockGroups());
    assertEquals("Missing blocks metrics not matching!",
        namesystem.getMissingBlocksCount(),
        namesystem.getMissingReplicatedBlocks() +
            namesystem.getMissingECBlockGroups());
    assertEquals("Missing blocks with replication factor one not matching!",
        namesystem.getMissingReplOneBlocksCount(),
        namesystem.getMissingReplicationOneBlocks());
    assertEquals("Bytes in future blocks metrics not matching!",
        namesystem.getBytesInFuture(),
        namesystem.getBytesInFutureReplicatedBlocks() +
            namesystem.getBytesInFutureECBlockGroups());
    assertEquals("Pending deletion blocks metrics not matching!",
        namesystem.getPendingDeletionBlocks(),
        namesystem.getPendingDeletionReplicatedBlocks() +
            namesystem.getPendingDeletionECBlocks());
  }

  /** Corrupt a block and ensure metrics reflects it */
  @Test
  public void testCorruptBlock() throws Exception {
    // Create a file with single block with two replicas
    final Path file = getTestPath("testCorruptBlock");
    final short replicaCount = 2;
    createFile(file, 100, replicaCount);
    DFSTestUtil.waitForReplication(fs, file, replicaCount, 15000);

    // Disable the heartbeats, so that no corrupted replica
    // can be fixed
    for (DataNode dn : cluster.getDataNodes()) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, true);
    }

    verifyZeroMetrics();
    verifyAggregatedMetricsTally();

    // Corrupt first replica of the block
    LocatedBlock block = NameNodeAdapter.getBlockLocations(
        cluster.getNameNode(), file.toString(), 0, 1).get(0);
    cluster.getNamesystem().writeLock();
    try {
      bm.findAndMarkBlockAsCorrupt(block.getBlock(), block.getLocations()[0],
          "STORAGE_ID", "TEST");
    } finally {
      cluster.getNamesystem().writeUnlock();
    }

    BlockManagerTestUtil.updateState(bm);
    MetricsRecordBuilder  rb = waitForDnMetricValue(NS_METRICS,
        "CorruptBlocks", 1L, 500);
    // Verify aggregated blocks metrics
    assertGauge("LowRedundancyBlocks", 1L, rb);
    assertGauge("PendingReplicationBlocks", 0L, rb);
    assertGauge("PendingReconstructionBlocks", 0L, rb);
    // Verify replicated blocks metrics
    assertGauge("LowRedundancyReplicatedBlocks", 1L, rb);
    assertGauge("CorruptReplicatedBlocks", 1L, rb);
    // Verify striped blocks metrics
    assertGauge("LowRedundancyECBlockGroups", 0L, rb);
    assertGauge("CorruptECBlockGroups", 0L, rb);

    verifyAggregatedMetricsTally();

    for (DataNode dn : cluster.getDataNodes()) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, false);
    }

    // Start block reconstruction work
    BlockManagerTestUtil.getComputedDatanodeWork(bm);

    BlockManagerTestUtil.updateState(bm);
    DFSTestUtil.waitForReplication(fs, file, replicaCount, 30000);
    rb = waitForDnMetricValue(NS_METRICS, "CorruptBlocks", 0L, 500);

    // Verify aggregated blocks metrics
    assertGauge("LowRedundancyBlocks", 0L, rb);
    assertGauge("CorruptBlocks", 0L, rb);
    assertGauge("PendingReplicationBlocks", 0L, rb);
    assertGauge("PendingReconstructionBlocks", 0L, rb);
    // Verify replicated blocks metrics
    assertGauge("LowRedundancyReplicatedBlocks", 0L, rb);
    assertGauge("CorruptReplicatedBlocks", 0L, rb);
    // Verify striped blocks metrics
    assertGauge("LowRedundancyECBlockGroups", 0L, rb);
    assertGauge("CorruptECBlockGroups", 0L, rb);

    verifyAggregatedMetricsTally();

    fs.delete(file, true);
    BlockManagerTestUtil.getComputedDatanodeWork(bm);
    // During the file deletion, both BlockManager#corruptReplicas and
    // BlockManager#pendingReplications will be updated, i.e., the records
    // for the blocks of the deleted file will be removed from both
    // corruptReplicas and pendingReplications. The corresponding
    // metrics (CorruptBlocks and PendingReplicationBlocks) will only be updated
    // when BlockManager#computeDatanodeWork is run where the
    // BlockManager#updateState is called. And in
    // BlockManager#computeDatanodeWork the metric ScheduledReplicationBlocks
    // will also be updated.
    BlockManagerTestUtil.updateState(bm);
    waitForDnMetricValue(NS_METRICS, "CorruptBlocks", 0L, 500);
    verifyZeroMetrics();
    verifyAggregatedMetricsTally();
  }

  @Test (timeout = 90000L)
  public void testStripedFileCorruptBlocks() throws Exception {
    final long fileLen = BLOCK_SIZE * 4;
    final Path ecFile = new Path(ecDir, "ecFile.log");
    DFSTestUtil.createFile(fs, ecFile, fileLen, (short) 1, 0L);
    StripedFileTestUtil.waitBlockGroupsReported(fs, ecFile.toString());

    // Disable the heartbeats, so that no corrupted replica
    // can be fixed
    for (DataNode dn : cluster.getDataNodes()) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, true);
    }

    verifyZeroMetrics();
    verifyAggregatedMetricsTally();

    // Corrupt first replica of the block
    LocatedBlocks lbs = fs.getClient().getNamenode().getBlockLocations(
        ecFile.toString(), 0, fileLen);
    assert lbs.get(0) instanceof LocatedStripedBlock;
    LocatedStripedBlock bg = (LocatedStripedBlock) (lbs.get(0));

    cluster.getNamesystem().writeLock();
    try {
      bm.findAndMarkBlockAsCorrupt(bg.getBlock(), bg.getLocations()[0],
          "STORAGE_ID", "TEST");
    } finally {
      cluster.getNamesystem().writeUnlock();
    }

    BlockManagerTestUtil.updateState(bm);
    MetricsRecordBuilder  rb = waitForDnMetricValue(NS_METRICS,
        "CorruptBlocks", 1L, 500);
    // Verify aggregated blocks metrics
    assertGauge("LowRedundancyBlocks", 1L, rb);
    assertGauge("PendingReplicationBlocks", 0L, rb);
    assertGauge("PendingReconstructionBlocks", 0L, rb);
    // Verify replica metrics
    assertGauge("LowRedundancyReplicatedBlocks", 0L, rb);
    assertGauge("CorruptReplicatedBlocks", 0L, rb);
    // Verify striped block groups metrics
    assertGauge("LowRedundancyECBlockGroups", 1L, rb);
    assertGauge("CorruptECBlockGroups", 1L, rb);

    verifyAggregatedMetricsTally();

    for (DataNode dn : cluster.getDataNodes()) {
      DataNodeTestUtils.setHeartbeatsDisabledForTests(dn, false);
    }

    // Start block reconstruction work
    BlockManagerTestUtil.getComputedDatanodeWork(bm);
    BlockManagerTestUtil.updateState(bm);
    StripedFileTestUtil.waitForReconstructionFinished(ecFile, fs, 3);

    rb = waitForDnMetricValue(NS_METRICS, "CorruptBlocks", 0L, 500);
    assertGauge("CorruptBlocks", 0L, rb);
    assertGauge("PendingReplicationBlocks", 0L, rb);
    assertGauge("PendingReconstructionBlocks", 0L, rb);
    // Verify replicated blocks metrics
    assertGauge("LowRedundancyReplicatedBlocks", 0L, rb);
    assertGauge("CorruptReplicatedBlocks", 0L, rb);
    // Verify striped blocks metrics
    assertGauge("LowRedundancyECBlockGroups", 0L, rb);
    assertGauge("CorruptECBlockGroups", 0L, rb);

    verifyAggregatedMetricsTally();

    fs.delete(ecFile, true);
    BlockManagerTestUtil.getComputedDatanodeWork(bm);
    // During the file deletion, both BlockManager#corruptReplicas and
    // BlockManager#pendingReplications will be updated, i.e., the records
    // for the blocks of the deleted file will be removed from both
    // corruptReplicas and pendingReplications. The corresponding
    // metrics (CorruptBlocks and PendingReplicationBlocks) will only be updated
    // when BlockManager#computeDatanodeWork is run where the
    // BlockManager#updateState is called. And in
    // BlockManager#computeDatanodeWork the metric ScheduledReplicationBlocks
    // will also be updated.
    BlockManagerTestUtil.updateState(bm);
    waitForDnMetricValue(NS_METRICS, "CorruptBlocks", 0L, 500);
    verifyZeroMetrics();
    verifyAggregatedMetricsTally();
  }

  /** Create excess blocks by reducing the replication factor for
   * for a file and ensure metrics reflects it
   */
  @Test
  public void testExcessBlocks() throws Exception {
    Path file = getTestPath("testExcessBlocks");
    createFile(file, 100, (short)2);
    NameNodeAdapter.setReplication(namesystem, file.toString(), (short)1);
    MetricsRecordBuilder rb = getMetrics(NS_METRICS);
    assertGauge("ExcessBlocks", 1L, rb);

    // verify ExcessBlocks metric is decremented and
    // excessReplicateMap is cleared after deleting a file
    fs.delete(file, true);
    rb = getMetrics(NS_METRICS);
    assertGauge("ExcessBlocks", 0L, rb);
    assertEquals(0L, bm.getExcessBlocksCount());
  }
  
  /** Test to ensure metrics reflects missing blocks */
  @Test
  public void testMissingBlock() throws Exception {
    // Create a file with single block with two replicas
    Path file = getTestPath("testMissingBlocks");
    createFile(file, 100, (short)1);
    
    // Corrupt the only replica of the block to result in a missing block
    LocatedBlock block = NameNodeAdapter.getBlockLocations(
        cluster.getNameNode(), file.toString(), 0, 1).get(0);
    cluster.getNamesystem().writeLock();
    try {
      bm.findAndMarkBlockAsCorrupt(block.getBlock(), block.getLocations()[0],
          "STORAGE_ID", "TEST");
    } finally {
      cluster.getNamesystem().writeUnlock();
    }
    Thread.sleep(1000); // Wait for block to be marked corrupt
    MetricsRecordBuilder rb = getMetrics(NS_METRICS);
    assertGauge("UnderReplicatedBlocks", 1L, rb);
    assertGauge("MissingBlocks", 1L, rb);
    assertGauge("MissingReplOneBlocks", 1L, rb);
    fs.delete(file, true);
    waitForDnMetricValue(NS_METRICS, "UnderReplicatedBlocks", 0L);
  }

  private void waitForDeletion() throws InterruptedException {
    // Wait for more than DATANODE_COUNT replication intervals to ensure all
    // the blocks pending deletion are sent for deletion to the datanodes.
    Thread.sleep(DFS_REDUNDANCY_INTERVAL * DATANODE_COUNT * 1000);
  }

  /**
   * Wait for the named gauge value from the metrics source to reach the
   * desired value.
   *
   * There's an initial delay then a spin cycle of sleep and poll. Because
   * all the tests use a shared FS instance, these tests are not independent;
   * that's why the initial sleep is in there.
   *
   * @param source metrics source
   * @param name gauge name
   * @param expected expected value
   * @return the last metrics record polled
   * @throws Exception if something went wrong.
   */
  private MetricsRecordBuilder waitForDnMetricValue(String source,
      String name, long expected) throws Exception {
    // initial wait
    waitForDeletion();
    return waitForDnMetricValue(source, name, expected,
        DFS_REDUNDANCY_INTERVAL * 500);
  }

  private MetricsRecordBuilder waitForDnMetricValue(String source,
      String name, long expected, long sleepInterval) throws Exception {
    MetricsRecordBuilder rb;
    long gauge;
    // Lots of retries are allowed for slow systems.
    // Fast ones will still exit early.
    int retries = DATANODE_COUNT * WAIT_GAUGE_VALUE_RETRIES;
    rb = getMetrics(source);
    gauge = MetricsAsserts.getLongGauge(name, rb);
    while (gauge != expected && (--retries > 0)) {
      Thread.sleep(sleepInterval);
      BlockManagerTestUtil.updateState(bm);
      rb = getMetrics(source);
      gauge = MetricsAsserts.getLongGauge(name, rb);
    }
    //at this point the assertion is valid or the retry count ran out
    assertGauge(name, expected, rb);
    return rb;
  }

  @Test
  public void testRenameMetrics() throws Exception {
    Path src = getTestPath("src");
    createFile(src, 100, (short)1);
    Path target = getTestPath("target");
    createFile(target, 100, (short)1);
    fs.rename(src, target, Rename.OVERWRITE);
    MetricsRecordBuilder rb = getMetrics(NN_METRICS);
    assertCounter("FilesRenamed", 1L, rb);
    assertCounter("FilesDeleted", 1L, rb);
  }
  
  /**
   * Test numGetBlockLocations metric   
   * 
   * Test initiates and performs file operations (create,read,close,open file )
   * which results in metrics changes. These metrics changes are updated and 
   * tested for correctness.
   * 
   *  create file operation does not increment numGetBlockLocation
   *  one read file operation increments numGetBlockLocation by 1
   *    
   * @throws IOException in case of an error
   */
  @Test
  public void testGetBlockLocationMetric() throws Exception {
    Path file1_Path = new Path(TEST_ROOT_DIR_PATH, "file1.dat");

    // When cluster starts first time there are no file  (read,create,open)
    // operations so metric GetBlockLocations should be 0.
    assertCounter("GetBlockLocations", 0L, getMetrics(NN_METRICS));

    //Perform create file operation
    createFile(file1_Path,100,(short)2);
  
    //Create file does not change numGetBlockLocations metric
    //expect numGetBlockLocations = 0 for previous and current interval 
    assertCounter("GetBlockLocations", 0L, getMetrics(NN_METRICS));
  
    // Open and read file operation increments GetBlockLocations
    // Perform read file operation on earlier created file
    readFile(fs, file1_Path);
    // Verify read file operation has incremented numGetBlockLocations by 1
    assertCounter("GetBlockLocations", 1L, getMetrics(NN_METRICS));

    // opening and reading file  twice will increment numGetBlockLocations by 2
    readFile(fs, file1_Path);
    readFile(fs, file1_Path);
    assertCounter("GetBlockLocations", 3L, getMetrics(NN_METRICS));
  }
  
  /**
   * Testing TransactionsSinceLastCheckpoint. Need a new cluster as
   * the other tests in here don't use HA. See HDFS-7501.
   */
  @Test(timeout = 300000)
  public void testTransactionSinceLastCheckpointMetrics() throws Exception {
    Random random = new Random();
    int retryCount = 0;
    while (retryCount < 5) {
      try {
        int basePort = 10060 + random.nextInt(100) * 2;
        MiniDFSNNTopology topology = new MiniDFSNNTopology()
            .addNameservice(new MiniDFSNNTopology.NSConf("ns1")
            .addNN(new MiniDFSNNTopology.NNConf("nn1").setHttpPort(basePort))
            .addNN(new MiniDFSNNTopology.NNConf("nn2").setHttpPort(basePort + 1)));

        HdfsConfiguration conf2 = new HdfsConfiguration();
        // Lower the checkpoint condition for purpose of testing.
        conf2.setInt(
            DFSConfigKeys.DFS_NAMENODE_CHECKPOINT_TXNS_KEY,
            100);
        // Check for checkpoint condition very often, for purpose of testing.
        conf2.setInt(
            DFSConfigKeys.DFS_NAMENODE_CHECKPOINT_CHECK_PERIOD_KEY,
            1);
        // Poll and follow ANN txns very often, for purpose of testing.
        conf2.setInt(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY, 1);
        MiniDFSCluster cluster2 = new MiniDFSCluster.Builder(conf2)
            .nnTopology(topology).numDataNodes(1).build();
        cluster2.waitActive();
        DistributedFileSystem fs2 = cluster2.getFileSystem(0);
        NameNode nn0 = cluster2.getNameNode(0);
        NameNode nn1 = cluster2.getNameNode(1);
        cluster2.transitionToActive(0);
        fs2.mkdirs(new Path("/tmp-t1"));
        fs2.mkdirs(new Path("/tmp-t2"));
        HATestUtil.waitForStandbyToCatchUp(nn0, nn1);
        // Test to ensure tracking works before the first-ever
        // checkpoint.
        assertEquals("SBN failed to track 2 transactions pre-checkpoint.",
            4L, // 2 txns added further when catch-up is called.
            cluster2.getNameNode(1).getNamesystem()
              .getTransactionsSinceLastCheckpoint());
        // Complete up to the boundary required for
        // an auto-checkpoint. Using 94 to expect fsimage
        // rounded at 100, as 4 + 94 + 2 (catch-up call) = 100.
        for (int i = 1; i <= 94; i++) {
          fs2.mkdirs(new Path("/tmp-" + i));
        }
        HATestUtil.waitForStandbyToCatchUp(nn0, nn1);
        // Assert 100 transactions in checkpoint.
        HATestUtil.waitForCheckpoint(cluster2, 1, ImmutableList.of(100));
        // Test to ensure number tracks the right state of
        // uncheckpointed edits, and does not go negative
        // (as fixed in HDFS-7501).
        assertEquals("Should be zero right after the checkpoint.",
            0L,
            cluster2.getNameNode(1).getNamesystem()
              .getTransactionsSinceLastCheckpoint());
        fs2.mkdirs(new Path("/tmp-t3"));
        fs2.mkdirs(new Path("/tmp-t4"));
        HATestUtil.waitForStandbyToCatchUp(nn0, nn1);
        // Test to ensure we track the right numbers after
        // the checkpoint resets it to zero again.
        assertEquals("SBN failed to track 2 added txns after the ckpt.",
            4L,
            cluster2.getNameNode(1).getNamesystem()
              .getTransactionsSinceLastCheckpoint());
        cluster2.shutdown();
        break;
      } catch (Exception e) {
        LOG.warn("Unable to set up HA cluster, exception thrown: " + e);
        retryCount++;
      }
    }
  }
  /**
   * Test NN checkpoint and transaction-related metrics.
   */
  @Test
  public void testTransactionAndCheckpointMetrics() throws Exception {
    long lastCkptTime = MetricsAsserts.getLongGauge("LastCheckpointTime",
        getMetrics(NS_METRICS));
    
    assertGauge("LastCheckpointTime", lastCkptTime, getMetrics(NS_METRICS));
    assertGauge("LastWrittenTransactionId", 4L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastCheckpoint", 4L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastLogRoll", 4L, getMetrics(NS_METRICS));
    
    fs.mkdirs(new Path(TEST_ROOT_DIR_PATH, "/tmp"));
    
    assertGauge("LastCheckpointTime", lastCkptTime, getMetrics(NS_METRICS));
    assertGauge("LastWrittenTransactionId", 5L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastCheckpoint", 5L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastLogRoll", 5L, getMetrics(NS_METRICS));
    
    cluster.getNameNodeRpc().rollEditLog();
    
    assertGauge("LastCheckpointTime", lastCkptTime, getMetrics(NS_METRICS));
    assertGauge("LastWrittenTransactionId", 7L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastCheckpoint", 7L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastLogRoll", 1L, getMetrics(NS_METRICS));
    
    cluster.getNameNodeRpc().setSafeMode(SafeModeAction.SAFEMODE_ENTER, false);
    cluster.getNameNodeRpc().saveNamespace(0, 0);
    cluster.getNameNodeRpc().setSafeMode(SafeModeAction.SAFEMODE_LEAVE, false);
    
    long newLastCkptTime = MetricsAsserts.getLongGauge("LastCheckpointTime",
        getMetrics(NS_METRICS));
    assertTrue(lastCkptTime < newLastCkptTime);
    assertGauge("LastWrittenTransactionId", 9L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastCheckpoint", 1L, getMetrics(NS_METRICS));
    assertGauge("TransactionsSinceLastLogRoll", 1L, getMetrics(NS_METRICS));
  }
  
  /**
   * Tests that the sync and block report metrics get updated on cluster
   * startup.
   */
  @Test
  public void testSyncAndBlockReportMetric() throws Exception {
    MetricsRecordBuilder rb = getMetrics(NN_METRICS);
    // We have one sync when the cluster starts up, just opening the journal
    assertCounter("SyncsNumOps", 4L, rb);
    // Each datanode reports in when the cluster comes up
    assertCounter("StorageBlockReportNumOps",
                  (long) DATANODE_COUNT * cluster.getStoragesPerDatanode(), rb);
    
    // Sleep for an interval+slop to let the percentiles rollover
    Thread.sleep((PERCENTILES_INTERVAL+1)*1000);
    
    // Check that the percentiles were updated
    assertQuantileGauges("Syncs1s", rb);
    assertQuantileGauges("StorageBlockReport1s", rb);
  }

  /**
   * Test NN ReadOps Count and WriteOps Count
   */
  @Test
  public void testReadWriteOps() throws Exception {
    MetricsRecordBuilder rb = getMetrics(NN_METRICS);
    long startWriteCounter = MetricsAsserts.getLongCounter("TransactionsNumOps",
        rb);
    Path file1_Path = new Path(TEST_ROOT_DIR_PATH, "ReadData.dat");

    //Perform create file operation
    createFile(file1_Path, 1024, (short) 2);

    // Perform read file operation on earlier created file
    readFile(fs, file1_Path);
    MetricsRecordBuilder rbNew = getMetrics(NN_METRICS);
    assertTrue(MetricsAsserts.getLongCounter("TransactionsNumOps", rbNew) >
        startWriteCounter);
  }

  /**
   * Test metrics indicating the number of active clients and the files under
   * construction
   */
  @Test(timeout = 60000)
  public void testNumActiveClientsAndFilesUnderConstructionMetrics()
      throws Exception {
    final Path file1 = getTestPath("testFileAdd1");
    createFile(file1, 100, (short) 3);
    assertGauge("NumActiveClients", 0L, getMetrics(NS_METRICS));
    assertGauge("NumFilesUnderConstruction", 0L, getMetrics(NS_METRICS));

    Path file2 = new Path("/testFileAdd2");
    FSDataOutputStream output2 = fs.create(file2);
    output2.writeBytes("Some test data");
    assertGauge("NumActiveClients", 1L, getMetrics(NS_METRICS));
    assertGauge("NumFilesUnderConstruction", 1L, getMetrics(NS_METRICS));

    Path file3 = new Path("/testFileAdd3");
    FSDataOutputStream output3 = fs.create(file3);
    output3.writeBytes("Some test data");
    assertGauge("NumActiveClients", 1L, getMetrics(NS_METRICS));
    assertGauge("NumFilesUnderConstruction", 2L, getMetrics(NS_METRICS));

    // create another DistributedFileSystem client
    DistributedFileSystem fs1 = (DistributedFileSystem) cluster
        .getNewFileSystemInstance(0);
    try {
      Path file4 = new Path("/testFileAdd4");
      FSDataOutputStream output4 = fs1.create(file4);
      output4.writeBytes("Some test data");
      assertGauge("NumActiveClients", 2L, getMetrics(NS_METRICS));
      assertGauge("NumFilesUnderConstruction", 3L, getMetrics(NS_METRICS));

      Path file5 = new Path("/testFileAdd35");
      FSDataOutputStream output5 = fs1.create(file5);
      output5.writeBytes("Some test data");
      assertGauge("NumActiveClients", 2L, getMetrics(NS_METRICS));
      assertGauge("NumFilesUnderConstruction", 4L, getMetrics(NS_METRICS));

      output2.close();
      output3.close();
      assertGauge("NumActiveClients", 1L, getMetrics(NS_METRICS));
      assertGauge("NumFilesUnderConstruction", 2L, getMetrics(NS_METRICS));

      output4.close();
      output5.close();
      assertGauge("NumActiveClients", 0L, getMetrics(NS_METRICS));
      assertGauge("NumFilesUnderConstruction", 0L, getMetrics(NS_METRICS));
    } finally {
      fs1.close();
    }
  }

  @Test
  public void testGenerateEDEKTime() throws IOException,
      NoSuchAlgorithmException {
    //Create new MiniDFSCluster with EncryptionZone configurations
    Configuration conf = new HdfsConfiguration();
    FileSystemTestHelper fsHelper = new FileSystemTestHelper();
    // Set up java key store
    String testRoot = fsHelper.getTestRootDir();
    File testRootDir = new File(testRoot).getAbsoluteFile();
    conf.set(CommonConfigurationKeysPublic.HADOOP_SECURITY_KEY_PROVIDER_PATH,
        JavaKeyStoreProvider.SCHEME_NAME + "://file" +
        new Path(testRootDir.toString(), "test.jks").toUri());
    conf.setBoolean(DFSConfigKeys
        .DFS_NAMENODE_DELEGATION_TOKEN_ALWAYS_USE_KEY, true);
    conf.setInt(DFSConfigKeys.DFS_NAMENODE_LIST_ENCRYPTION_ZONES_NUM_RESPONSES,
        2);
    File basedir = new File(MiniDFSCluster.getBaseDirectory(),
        GenericTestUtils.getMethodName());

    try (MiniDFSCluster clusterEDEK = new MiniDFSCluster.Builder(conf, basedir)
        .numDataNodes(1).build()) {

      DistributedFileSystem fsEDEK =
          clusterEDEK.getFileSystem();
      FileSystemTestWrapper fsWrapper = new FileSystemTestWrapper(
          fsEDEK);
      HdfsAdmin dfsAdmin = new HdfsAdmin(clusterEDEK.getURI(),
          conf);
      fsEDEK.getClient().setKeyProvider(
          clusterEDEK.getNameNode().getNamesystem()
              .getProvider());

      String testKey = "test_key";
      DFSTestUtil.createKey(testKey, clusterEDEK, conf);

      final Path zoneParent = new Path("/zones");
      final Path zone1 = new Path(zoneParent, "zone1");
      fsWrapper.mkdir(zone1, FsPermission.getDirDefault(), true);
      dfsAdmin.createEncryptionZone(zone1, "test_key", EnumSet.of(
          CreateEncryptionZoneFlag.NO_TRASH));

      MetricsRecordBuilder rb = getMetrics(NN_METRICS);

      for (int i = 0; i < 3; i++) {
        Path filePath = new Path("/zones/zone1/testfile-" + i);
        DFSTestUtil.createFile(fsEDEK, filePath, 1024, (short) 3, 1L);

        assertQuantileGauges("GenerateEDEKTime1s", rb);
      }
    }
  }

  @Test
  public void testResourceCheck() throws Exception {
    HdfsConfiguration conf = new HdfsConfiguration();
    File basedir = new File(MiniDFSCluster.getBaseDirectory(),
        GenericTestUtils.getMethodName());
    MiniDFSCluster tmpCluster = new MiniDFSCluster.Builder(conf, basedir)
        .numDataNodes(0)
        .nnTopology(MiniDFSNNTopology.simpleHATopology())
        .build();
    try {
      MockNameNodeResourceChecker mockResourceChecker =
          new MockNameNodeResourceChecker(conf);
      tmpCluster.getNameNode(0).getNamesystem()
          .setNNResourceChecker(mockResourceChecker);
      NNHAServiceTarget haTarget = new NNHAServiceTarget(conf,
          DFSUtil.getNamenodeNameServiceId(
              new HdfsConfiguration()), "nn1");
      HAServiceProtocol rpc = haTarget.getHealthMonitorProxy(conf, conf.getInt(
          HA_HM_RPC_TIMEOUT_KEY, HA_HM_RPC_TIMEOUT_DEFAULT));

      MetricsRecordBuilder rb = getMetrics(NN_METRICS);
      for (long i = 0; i < 10; i++) {
        rpc.monitorHealth();
        assertQuantileGauges("ResourceCheckTime1s", rb);
      }
    } finally {
      if (tmpCluster != null) {
        tmpCluster.shutdown();
      }
    }
  }

  @Test
  public void testEditLogTailing() throws Exception {
    HdfsConfiguration conf = new HdfsConfiguration();
    conf.setInt(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY, 1);
    conf.setInt(DFSConfigKeys.DFS_METRICS_PERCENTILES_INTERVALS_KEY, 60);
    MiniDFSCluster dfsCluster = null;
    try {
      dfsCluster = new MiniDFSCluster.Builder(conf)
          .numDataNodes(0)
          .nnTopology(MiniDFSNNTopology.simpleHATopology())
          .build();
      DistributedFileSystem dfs = dfsCluster.getFileSystem(0);
      dfsCluster.transitionToActive(0);
      dfsCluster.waitActive();

      Path testDir = new Path("/testdir");
      dfs.mkdir(testDir, FsPermission.getDefault());

      dfsCluster.getNameNodeRpc(0).rollEditLog();
      Thread.sleep(2 * 1000);

      // We need to get the metrics for the SBN (excluding the NN from dfs
      // cluster created in setUp() and the ANN).
      MetricsRecordBuilder rb = getMetrics(NN_METRICS+"-2");
      assertQuantileGauges("EditLogTailTime60s", rb);
      assertQuantileGauges("EditLogFetchTime60s", rb);
      assertQuantileGauges("NumEditLogLoaded60s", rb, "Count");
      assertQuantileGauges("EditLogTailInterval60s", rb);
      assertCounterGt("EditLogTailTimeNumOps", 0L, rb);
      assertCounterGt("EditLogFetchTimeNumOps", 0L, rb);
      assertCounterGt("NumEditLogLoadedNumOps", 0L, rb);
      assertCounterGt("EditLogTailIntervalNumOps", 0L, rb);
    } finally {
      if (dfsCluster != null) {
        dfsCluster.shutdown();
      }
    }

  }
}
