| /** |
| * 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.metrics; |
| |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.metrics2.MetricsJsonBuilder; |
| import org.apache.hadoop.metrics2.lib.MutableRollingAverages; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.Map; |
| import java.util.concurrent.ThreadLocalRandom; |
| |
| /** |
| * This class maintains DataNode peer metrics (e.g. numOps, AvgTime, etc.) for |
| * various peer operations. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class DataNodePeerMetrics { |
| |
| public static final Logger LOG = LoggerFactory.getLogger( |
| DataNodePeerMetrics.class); |
| |
| private final MutableRollingAverages sendPacketDownstreamRollingAverages; |
| |
| private final String name; |
| |
| /** |
| * Threshold in milliseconds below which a DataNode is definitely not slow. |
| */ |
| private static final long LOW_THRESHOLD_MS = 5; |
| private static final long MIN_OUTLIER_DETECTION_NODES = 10; |
| |
| private final OutlierDetector slowNodeDetector; |
| |
| /** |
| * Minimum number of packet send samples which are required to qualify |
| * for outlier detection. If the number of samples is below this then |
| * outlier detection is skipped. |
| */ |
| @VisibleForTesting |
| static final long MIN_OUTLIER_DETECTION_SAMPLES = 1000; |
| |
| public DataNodePeerMetrics(final String name) { |
| this.name = name; |
| this.slowNodeDetector = new OutlierDetector(MIN_OUTLIER_DETECTION_NODES, |
| LOW_THRESHOLD_MS); |
| sendPacketDownstreamRollingAverages = new MutableRollingAverages("Time"); |
| } |
| |
| public String name() { |
| return name; |
| } |
| |
| /** |
| * Creates an instance of DataNodePeerMetrics, used for registration. |
| */ |
| public static DataNodePeerMetrics create(String dnName) { |
| final String name = "DataNodePeerActivity-" + (dnName.isEmpty() |
| ? "UndefinedDataNodeName" + ThreadLocalRandom.current().nextInt() |
| : dnName.replace(':', '-')); |
| |
| return new DataNodePeerMetrics(name); |
| } |
| |
| /** |
| * Adds invocation and elapsed time of SendPacketDownstream for peer. |
| * <p> |
| * The caller should pass in a well-formatted peerAddr. e.g. |
| * "[192.168.1.110:1010]" is good. This will be translated into a full |
| * qualified metric name, e.g. "[192.168.1.110:1010]AvgTime". |
| * </p> |
| */ |
| public void addSendPacketDownstream( |
| final String peerAddr, |
| final long elapsedMs) { |
| sendPacketDownstreamRollingAverages.add(peerAddr, elapsedMs); |
| } |
| |
| /** |
| * Dump SendPacketDownstreamRollingAvgTime metrics as JSON. |
| */ |
| public String dumpSendPacketDownstreamAvgInfoAsJson() { |
| final MetricsJsonBuilder builder = new MetricsJsonBuilder(null); |
| sendPacketDownstreamRollingAverages.snapshot(builder, true); |
| return builder.toString(); |
| } |
| |
| /** |
| * Collects states maintained in {@link ThreadLocal}, if any. |
| */ |
| public void collectThreadLocalStates() { |
| sendPacketDownstreamRollingAverages.collectThreadLocalStates(); |
| } |
| |
| /** |
| * Retrieve the set of dataNodes that look significantly slower |
| * than their peers. |
| */ |
| public Map<String, Double> getOutliers() { |
| // This maps the metric name to the aggregate latency. |
| // The metric name is the datanode ID. |
| final Map<String, Double> stats = |
| sendPacketDownstreamRollingAverages.getStats( |
| MIN_OUTLIER_DETECTION_SAMPLES); |
| LOG.trace("DataNodePeerMetrics: Got stats: {}", stats); |
| |
| return slowNodeDetector.getOutliers(stats); |
| } |
| |
| public MutableRollingAverages getSendPacketDownstreamRollingAverages() { |
| return sendPacketDownstreamRollingAverages; |
| } |
| } |