/**
* 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.hbase.util;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Random;
import java.util.Set;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.ClusterStatus;
import org.apache.hadoop.hbase.HBaseCluster;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.IntegrationTestingUtility;
import org.apache.hadoop.hbase.IntegrationTestDataIngestWithChaosMonkey;
import org.apache.hadoop.hbase.ServerLoad;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.util.StringUtils;
import org.apache.hadoop.util.ToolRunner;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.protobuf.ServiceException;
/**
* A utility to injects faults in a running cluster.
* <p>
* ChaosMonkey defines Action's and Policy's. Actions are sequences of events, like
* - Select a random server to kill
* - Sleep for 5 sec
* - Start the server on the same host
* Actions can also be complex events, like rolling restart of all of the servers.
* <p>
* Policies on the other hand are responsible for executing the actions based on a strategy.
* The default policy is to execute a random action every minute based on predefined action
* weights. ChaosMonkey executes predefined named policies until it is stopped. More than one
* policy can be active at any time.
* <p>
* Chaos monkey can be run from the command line, or can be invoked from integration tests.
* See {@link IntegrationTestDataIngestWithChaosMonkey} or other integration tests that use
* chaos monkey for code examples.
* <p>
* ChaosMonkey class is indeed inspired by the Netflix's same-named tool:
* http://techblog.netflix.com/2012/07/chaos-monkey-released-into-wild.html
*/
public class ChaosMonkey extends AbstractHBaseTool implements Stoppable {
private static final Log LOG = LogFactory.getLog(ChaosMonkey.class);
private static final long ONE_SEC = 1000;
private static final long FIVE_SEC = 5 * ONE_SEC;
private static final long ONE_MIN = 60 * ONE_SEC;
private static final long TIMEOUT = ONE_MIN;
final IntegrationTestingUtility util;
/**
* Construct a new ChaosMonkey
* @param util the HBaseIntegrationTestingUtility already configured
* @param policies names of pre-defined policies to use
*/
public ChaosMonkey(IntegrationTestingUtility util, String... policies) {
this.util = util;
setPoliciesByName(policies);
}
/**
* Construct a new ChaosMonkey
* @param util the HBaseIntegrationTestingUtility already configured
* @param policies custom policies to use
*/
public ChaosMonkey(IntegrationTestingUtility util, Policy... policies) {
this.util = util;
this.policies = policies;
}
private void setPoliciesByName(String... policies) {
this.policies = new Policy[policies.length];
for (int i=0; i < policies.length; i++) {
this.policies[i] = NAMED_POLICIES.get(policies[i]);
}
}
/**
* Context for Action's
*/
private static class ActionContext {
private IntegrationTestingUtility util;
ActionContext(IntegrationTestingUtility util) {
this.util = util;
}
IntegrationTestingUtility getHaseIntegrationTestingUtility() {
return util;
}
HBaseCluster getHBaseCluster() {
return util.getHBaseClusterInterface();
}
}
/**
* A (possibly mischievous) action that the ChaosMonkey can perform.
*/
public static class Action {
// TODO: interesting question - should actions be implemented inside
// ChaosMonkey, or outside? If they are inside (initial), the class becomes
// huge and all-encompassing; if they are outside ChaosMonkey becomes just
// a random task scheduler. For now, keep inside.
protected ActionContext context;
protected HBaseCluster cluster;
protected ClusterStatus initialStatus;
protected ServerName[] initialServers;
void init(ActionContext context) throws Exception {
this.context = context;
cluster = context.getHBaseCluster();
initialStatus = cluster.getInitialClusterStatus();
Collection<ServerName> regionServers = initialStatus.getServers();
initialServers = regionServers.toArray(new ServerName[regionServers.size()]);
}
void perform() throws Exception { };
// TODO: perhaps these methods should be elsewhere?
/** Returns current region servers */
protected ServerName[] getCurrentServers() throws IOException {
Collection<ServerName> regionServers = cluster.getClusterStatus().getServers();
return regionServers.toArray(new ServerName[regionServers.size()]);
}
protected void killMaster(ServerName server) throws IOException {
LOG.info("Killing master:" + server);
cluster.killMaster(server);
cluster.waitForMasterToStop(server, TIMEOUT);
LOG.info("Killed master server:" + server);
}
protected void startMaster(ServerName server) throws IOException {
LOG.info("Starting master:" + server.getHostname());
cluster.startMaster(server.getHostname());
cluster.waitForActiveAndReadyMaster(TIMEOUT);
LOG.info("Started master: " + server);
}
protected void killRs(ServerName server) throws IOException {
LOG.info("Killing region server:" + server);
cluster.killRegionServer(server);
cluster.waitForRegionServerToStop(server, TIMEOUT);
LOG.info("Killed region server:" + server + ". Reported num of rs:"
+ cluster.getClusterStatus().getServersSize());
}
protected void startRs(ServerName server) throws IOException {
LOG.info("Starting region server:" + server.getHostname());
cluster.startRegionServer(server.getHostname());
cluster.waitForRegionServerToStart(server.getHostname(), TIMEOUT);
LOG.info("Started region server:" + server + ". Reported num of rs:"
+ cluster.getClusterStatus().getServersSize());
}
}
private static class RestartActionBase extends Action {
long sleepTime; // how long should we sleep
public RestartActionBase(long sleepTime) {
this.sleepTime = sleepTime;
}
void sleep(long sleepTime) {
LOG.info("Sleeping for:" + sleepTime);
Threads.sleep(sleepTime);
}
void restartMaster(ServerName server, long sleepTime) throws IOException {
killMaster(server);
sleep(sleepTime);
startMaster(server);
}
void restartRs(ServerName server, long sleepTime) throws IOException {
killRs(server);
sleep(sleepTime);
startRs(server);
}
}
public static class RestartActiveMaster extends RestartActionBase {
public RestartActiveMaster(long sleepTime) {
super(sleepTime);
}
@Override
void perform() throws Exception {
LOG.info("Performing action: Restart active master");
ServerName master = cluster.getClusterStatus().getMaster();
restartMaster(master, sleepTime);
}
}
public static class RestartRandomRs extends RestartActionBase {
public RestartRandomRs(long sleepTime) {
super(sleepTime);
}
@Override
void perform() throws Exception {
LOG.info("Performing action: Restart random region server");
ServerName server = selectRandomItem(getCurrentServers());
restartRs(server, sleepTime);
}
}
public static class RestartRsHoldingMeta extends RestartRandomRs {
public RestartRsHoldingMeta(long sleepTime) {
super(sleepTime);
}
@Override
void perform() throws Exception {
LOG.info("Performing action: Restart region server holding META");
ServerName server = cluster.getServerHoldingMeta();
if (server == null) {
LOG.warn("No server is holding .META. right now.");
return;
}
restartRs(server, sleepTime);
}
}
public static class RestartRsHoldingRoot extends RestartRandomRs {
public RestartRsHoldingRoot(long sleepTime) {
super(sleepTime);
}
@Override
void perform() throws Exception {
LOG.info("Performing action: Restart region server holding ROOT");
ServerName server = cluster.getServerHoldingMeta();
if (server == null) {
LOG.warn("No server is holding -ROOT- right now.");
return;
}
restartRs(server, sleepTime);
}
}
/**
* Restarts a ratio of the running regionservers at the same time
*/
public static class BatchRestartRs extends RestartActionBase {
float ratio; //ratio of regionservers to restart
public BatchRestartRs(long sleepTime, float ratio) {
super(sleepTime);
this.ratio = ratio;
}
@Override
void perform() throws Exception {
LOG.info(String.format("Performing action: Batch restarting %d%% of region servers",
(int)(ratio * 100)));
List<ServerName> selectedServers = selectRandomItems(getCurrentServers(), ratio);
for (ServerName server : selectedServers) {
LOG.info("Killing region server:" + server);
cluster.killRegionServer(server);
}
for (ServerName server : selectedServers) {
cluster.waitForRegionServerToStop(server, TIMEOUT);
}
LOG.info("Killed " + selectedServers.size() + " region servers. Reported num of rs:"
+ cluster.getClusterStatus().getServersSize());
sleep(sleepTime);
for (ServerName server : selectedServers) {
LOG.info("Starting region server:" + server.getHostname());
cluster.startRegionServer(server.getHostname());
}
for (ServerName server : selectedServers) {
cluster.waitForRegionServerToStart(server.getHostname(), TIMEOUT);
}
LOG.info("Started " + selectedServers.size() +" region servers. Reported num of rs:"
+ cluster.getClusterStatus().getServersSize());
}
}
/**
* Restarts a ratio of the regionservers in a rolling fashion. At each step, either kills a
* server, or starts one, sleeping randomly (0-sleepTime) in between steps.
*/
public static class RollingBatchRestartRs extends BatchRestartRs {
public RollingBatchRestartRs(long sleepTime, float ratio) {
super(sleepTime, ratio);
}
@Override
void perform() throws Exception {
LOG.info(String.format("Performing action: Rolling batch restarting %d%% of region servers",
(int)(ratio * 100)));
Random random = new Random();
List<ServerName> selectedServers = selectRandomItems(getCurrentServers(), ratio);
Queue<ServerName> serversToBeKilled = new LinkedList<ServerName>(selectedServers);
Queue<ServerName> deadServers = new LinkedList<ServerName>();
//
while (!serversToBeKilled.isEmpty() || !deadServers.isEmpty()) {
boolean action = true; //action true = kill server, false = start server
if (serversToBeKilled.isEmpty() || deadServers.isEmpty()) {
action = deadServers.isEmpty();
} else {
action = random.nextBoolean();
}
if (action) {
ServerName server = serversToBeKilled.remove();
killRs(server);
deadServers.add(server);
} else {
ServerName server = deadServers.remove();
startRs(server);
}
sleep(random.nextInt((int)sleepTime));
}
}
}
public static class UnbalanceRegionsAction extends Action {
private double fractionOfRegions;
private double fractionOfServers;
private Random random = new Random();
/**
* Unbalances the regions on the cluster by choosing "target" servers, and moving
* some regions from each of the non-target servers to random target servers.
* @param fractionOfRegions Fraction of regions to move from each server.
* @param fractionOfServers Fraction of servers to be chosen as targets.
*/
public UnbalanceRegionsAction(double fractionOfRegions, double fractionOfServers) {
this.fractionOfRegions = fractionOfRegions;
this.fractionOfServers = fractionOfServers;
}
@Override
void perform() throws Exception {
LOG.info("Unbalancing regions");
ClusterStatus status = this.cluster.getClusterStatus();
List<ServerName> victimServers = new LinkedList<ServerName>(status.getServers());
int targetServerCount = (int)Math.ceil(fractionOfServers * victimServers.size());
List<byte[]> targetServers = new ArrayList<byte[]>(targetServerCount);
for (int i = 0; i < targetServerCount; ++i) {
int victimIx = random.nextInt(victimServers.size());
String serverName = victimServers.remove(victimIx).getServerName();
targetServers.add(Bytes.toBytes(serverName));
}
List<byte[]> victimRegions = new LinkedList<byte[]>();
for (ServerName server : victimServers) {
ServerLoad serverLoad = status.getLoad(server);
// Ugh.
List<byte[]> regions = new LinkedList<byte[]>(serverLoad.getRegionsLoad().keySet());
int victimRegionCount = (int)Math.ceil(fractionOfRegions * regions.size());
LOG.debug("Removing " + victimRegionCount + " regions from " + server.getServerName());
for (int i = 0; i < victimRegionCount; ++i) {
int victimIx = random.nextInt(regions.size());
String regionId = HRegionInfo.encodeRegionName(regions.remove(victimIx));
victimRegions.add(Bytes.toBytes(regionId));
}
}
LOG.info("Moving " + victimRegions.size() + " regions from " + victimServers.size()
+ " servers to " + targetServers.size() + " different servers");
HBaseAdmin admin = this.context.getHaseIntegrationTestingUtility().getHBaseAdmin();
for (byte[] victimRegion : victimRegions) {
int targetIx = random.nextInt(targetServers.size());
admin.move(victimRegion, targetServers.get(targetIx));
}
}
}
public static class ForceBalancerAction extends Action {
@Override
void perform() throws Exception {
LOG.info("Balancing regions");
HBaseAdmin admin = this.context.getHaseIntegrationTestingUtility().getHBaseAdmin();
boolean result = admin.balancer();
if (!result) {
LOG.error("Balancer didn't succeed");
}
}
}
/**
* A context for a Policy
*/
private static class PolicyContext extends ActionContext {
PolicyContext(IntegrationTestingUtility util) {
super(util);
}
}
/**
* A policy to introduce chaos to the cluster
*/
public static abstract class Policy extends StoppableImplementation implements Runnable {
PolicyContext context;
public void init(PolicyContext context) throws Exception {
this.context = context;
}
}
/**
* A policy, which picks a random action according to the given weights,
* and performs it every configurable period.
*/
public static class PeriodicRandomActionPolicy extends Policy {
private long periodMs;
private List<Pair<Action, Integer>> actions;
public PeriodicRandomActionPolicy(long periodMs, List<Pair<Action, Integer>> actions) {
this.periodMs = periodMs;
this.actions = actions;
}
public PeriodicRandomActionPolicy(long periodMs, Pair<Action, Integer>... actions) {
// We don't expect it to be modified.
this(periodMs, Arrays.asList(actions));
}
public PeriodicRandomActionPolicy(long periodMs, Action... actions) {
this.periodMs = periodMs;
this.actions = new ArrayList<Pair<Action, Integer>>(actions.length);
for (Action action : actions) {
this.actions.add(new Pair<Action, Integer>(action, 1));
}
}
@Override
public void run() {
//add some jitter
int jitter = new Random().nextInt((int)periodMs);
LOG.info("Sleeping for " + jitter + " to add jitter");
Threads.sleep(jitter);
while (!isStopped()) {
long start = System.currentTimeMillis();
Action action = selectWeightedRandomItem(actions);
try {
action.perform();
} catch (Exception ex) {
LOG.warn("Exception occured during performing action: "
+ StringUtils.stringifyException(ex));
}
long sleepTime = periodMs - (System.currentTimeMillis() - start);
if (sleepTime > 0) {
LOG.info("Sleeping for:" + sleepTime);
Threads.sleep(sleepTime);
}
}
}
@Override
public void init(PolicyContext context) throws Exception {
super.init(context);
LOG.info("Using ChaosMonkey Policy: " + this.getClass() + ", period:" + periodMs);
for (Pair<Action, Integer> action : actions) {
action.getFirst().init(this.context);
}
}
}
/** Selects a random item from the given items */
static <T> T selectRandomItem(T[] items) {
Random random = new Random();
return items[random.nextInt(items.length)];
}
/** Selects a random item from the given items with weights*/
static <T> T selectWeightedRandomItem(List<Pair<T, Integer>> items) {
Random random = new Random();
int totalWeight = 0;
for (Pair<T, Integer> pair : items) {
totalWeight += pair.getSecond();
}
int cutoff = random.nextInt(totalWeight);
int cummulative = 0;
T item = null;
//warn: O(n)
for (int i=0; i<items.size(); i++) {
int curWeight = items.get(i).getSecond();
if ( cutoff < cummulative + curWeight) {
item = items.get(i).getFirst();
break;
}
cummulative += curWeight;
}
return item;
}
/** Selects and returns ceil(ratio * items.length) random items from the given array */
static <T> List<T> selectRandomItems(T[] items, float ratio) {
Random random = new Random();
int remaining = (int)Math.ceil(items.length * ratio);
List<T> selectedItems = new ArrayList<T>(remaining);
for (int i=0; i<items.length && remaining > 0; i++) {
if (random.nextFloat() < ((float)remaining/(items.length-i))) {
selectedItems.add(items[i]);
remaining--;
}
}
return selectedItems;
}
/**
* All actions that deal with RS's with the following weights (relative probabilities):
* - Restart active master (sleep 5 sec) : 2
* - Restart random regionserver (sleep 5 sec) : 2
* - Restart random regionserver (sleep 60 sec) : 2
* - Restart META regionserver (sleep 5 sec) : 1
* - Restart ROOT regionserver (sleep 5 sec) : 1
* - Batch restart of 50% of regionservers (sleep 5 sec) : 2
* - Rolling restart of 100% of regionservers (sleep 5 sec) : 2
*/
@SuppressWarnings("unchecked")
private static final List<Pair<Action, Integer>> ALL_ACTIONS = Lists.newArrayList(
new Pair<Action,Integer>(new RestartActiveMaster(FIVE_SEC), 2),
new Pair<Action,Integer>(new RestartRandomRs(FIVE_SEC), 2),
new Pair<Action,Integer>(new RestartRandomRs(ONE_MIN), 2),
new Pair<Action,Integer>(new RestartRsHoldingMeta(FIVE_SEC), 1),
new Pair<Action,Integer>(new RestartRsHoldingRoot(FIVE_SEC), 1),
new Pair<Action,Integer>(new BatchRestartRs(FIVE_SEC, 0.5f), 2),
new Pair<Action,Integer>(new RollingBatchRestartRs(FIVE_SEC, 1.0f), 2)
);
public static final String EVERY_MINUTE_RANDOM_ACTION_POLICY = "EVERY_MINUTE_RANDOM_ACTION_POLICY";
private Policy[] policies;
private Thread[] monkeyThreads;
public void start() throws Exception {
monkeyThreads = new Thread[policies.length];
for (int i=0; i<policies.length; i++) {
policies[i].init(new PolicyContext(this.util));
Thread monkeyThread = new Thread(policies[i]);
monkeyThread.start();
monkeyThreads[i] = monkeyThread;
}
}
@Override
public void stop(String why) {
for (Policy policy : policies) {
policy.stop(why);
}
}
@Override
public boolean isStopped() {
return policies[0].isStopped();
}
/**
* Wait for ChaosMonkey to stop.
* @throws InterruptedException
*/
public void waitForStop() throws InterruptedException {
for (Thread monkeyThread : monkeyThreads) {
monkeyThread.join();
}
}
private static final Map<String, Policy> NAMED_POLICIES = Maps.newHashMap();
static {
NAMED_POLICIES.put(EVERY_MINUTE_RANDOM_ACTION_POLICY,
new PeriodicRandomActionPolicy(ONE_MIN, ALL_ACTIONS));
}
@Override
protected void addOptions() {
addOptWithArg("policy", "a named policy defined in ChaosMonkey.java. Possible values: "
+ NAMED_POLICIES.keySet());
//we can add more options, and make policies more configurable
}
@Override
protected void processOptions(CommandLine cmd) {
String[] policies = cmd.getOptionValues("policy");
if (policies != null) {
setPoliciesByName(policies);
}
}
@Override
protected int doWork() throws Exception {
start();
waitForStop();
return 0;
}
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
IntegrationTestingUtility.setUseDistributedCluster(conf);
IntegrationTestingUtility util = new IntegrationTestingUtility(conf);
util.initializeCluster(1);
ChaosMonkey monkey = new ChaosMonkey(util, EVERY_MINUTE_RANDOM_ACTION_POLICY);
int ret = ToolRunner.run(conf, monkey, args);
System.exit(ret);
}
}