| /* |
| * Copyright 2015-present Open Networking Foundation |
| * |
| * Licensed 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.onosproject.store.cluster.impl; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import java.util.Map; |
| |
| import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics; |
| import org.onosproject.cluster.NodeId; |
| |
| import com.google.common.collect.Maps; |
| |
| /** |
| * Phi Accrual failure detector. |
| * <p> |
| * Based on a paper titled: "The φ Accrual Failure Detector" by Hayashibara, et al. |
| */ |
| public class PhiAccrualFailureDetector { |
| private final Map<NodeId, History> states = Maps.newConcurrentMap(); |
| |
| // Default value |
| private static final int DEFAULT_WINDOW_SIZE = 250; |
| private static final int DEFAULT_MIN_SAMPLES = 25; |
| private static final double DEFAULT_PHI_FACTOR = 1.0 / Math.log(10.0); |
| |
| // If a node does not have any heartbeats, this is the phi |
| // value to report. Indicates the node is inactive (from the |
| // detectors perspective. |
| private static final double DEFAULT_BOOTSTRAP_PHI_VALUE = 100.0; |
| |
| |
| private int minSamples = DEFAULT_MIN_SAMPLES; |
| private double phiFactor = DEFAULT_PHI_FACTOR; |
| private double bootstrapPhiValue = DEFAULT_BOOTSTRAP_PHI_VALUE; |
| |
| /** |
| * Report a new heart beat for the specified node id. |
| * @param nodeId node id |
| */ |
| public void report(NodeId nodeId) { |
| report(nodeId, System.currentTimeMillis()); |
| } |
| |
| /** |
| * Report a new heart beat for the specified node id. |
| * @param nodeId node id |
| * @param arrivalTime arrival time |
| */ |
| public void report(NodeId nodeId, long arrivalTime) { |
| checkNotNull(nodeId, "NodeId must not be null"); |
| checkArgument(arrivalTime >= 0, "arrivalTime must not be negative"); |
| History nodeState = |
| states.computeIfAbsent(nodeId, key -> new History()); |
| synchronized (nodeState) { |
| long latestHeartbeat = nodeState.latestHeartbeatTime(); |
| if (latestHeartbeat != -1) { |
| nodeState.samples().addValue(arrivalTime - latestHeartbeat); |
| } |
| nodeState.setLatestHeartbeatTime(arrivalTime); |
| } |
| } |
| |
| /** |
| * Resets the failure detector for the given node. |
| * |
| * @param nodeId node identifier for the node for which to reset the failure detector |
| */ |
| public void reset(NodeId nodeId) { |
| states.put(nodeId, new History()); |
| } |
| |
| /** |
| * Compute phi for the specified node id. |
| * @param nodeId node id |
| * @return phi value |
| */ |
| public double phi(NodeId nodeId) { |
| checkNotNull(nodeId, "NodeId must not be null"); |
| if (!states.containsKey(nodeId)) { |
| return bootstrapPhiValue; |
| } |
| History nodeState = states.get(nodeId); |
| synchronized (nodeState) { |
| long latestHeartbeat = nodeState.latestHeartbeatTime(); |
| DescriptiveStatistics samples = nodeState.samples(); |
| if (latestHeartbeat == -1 || samples.getN() < minSamples) { |
| return 0.0; |
| } |
| return computePhi(samples, latestHeartbeat, System.currentTimeMillis()); |
| } |
| } |
| |
| private double computePhi(DescriptiveStatistics samples, long tLast, long tNow) { |
| long size = samples.getN(); |
| long t = tNow - tLast; |
| return (size > 0) |
| ? phiFactor * t / samples.getMean() |
| : bootstrapPhiValue; |
| } |
| |
| |
| private void setMinSamples(int samples) { |
| minSamples = samples; |
| } |
| |
| private void setPhiFactor(double factor) { |
| phiFactor = factor; |
| } |
| |
| private void setBootstrapPhiValue(double phiValue) { |
| bootstrapPhiValue = phiValue; |
| } |
| |
| |
| private static class History { |
| DescriptiveStatistics samples = |
| new DescriptiveStatistics(DEFAULT_WINDOW_SIZE); |
| long lastHeartbeatTime = -1; |
| |
| public DescriptiveStatistics samples() { |
| return samples; |
| } |
| |
| public long latestHeartbeatTime() { |
| return lastHeartbeatTime; |
| } |
| |
| public void setLatestHeartbeatTime(long value) { |
| lastHeartbeatTime = value; |
| } |
| } |
| } |