org.apache.hadoop.hbase.chaos.actions.RollingBatchRestartRsAction.java Source code

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Here is the source code for org.apache.hadoop.hbase.chaos.actions.RollingBatchRestartRsAction.java

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/**
 * 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.chaos.actions;

import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;

import org.apache.commons.lang.math.RandomUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.chaos.monkies.PolicyBasedChaosMonkey;

/**
 * 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 class RollingBatchRestartRsAction extends BatchRestartRsAction {
    private static Log LOG = LogFactory.getLog(RollingBatchRestartRsAction.class);

    public RollingBatchRestartRsAction(long sleepTime, float ratio) {
        super(sleepTime, ratio);
    }

    @Override
    public void perform() throws Exception {
        LOG.info(String.format("Performing action: Rolling batch restarting %d%% of region servers",
                (int) (ratio * 100)));
        List<ServerName> selectedServers = PolicyBasedChaosMonkey.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 = RandomUtils.nextBoolean();
            }

            if (action) {
                ServerName server = serversToBeKilled.remove();
                try {
                    killRs(server);
                } catch (org.apache.hadoop.util.Shell.ExitCodeException e) {
                    // We've seen this in test runs where we timeout but the kill went through. HBASE-9743
                    // So, add to deadServers even if exception so the start gets called.
                    LOG.info("Problem killing but presume successful; code=" + e.getExitCode(), e);
                }
                deadServers.add(server);
            } else {
                try {
                    ServerName server = deadServers.remove();
                    startRs(server);
                } catch (org.apache.hadoop.util.Shell.ExitCodeException e) {
                    // The start may fail but better to just keep going though we may lose server.
                    //
                    LOG.info("Problem starting, will retry; code=" + e.getExitCode(), e);
                }
            }

            sleep(RandomUtils.nextInt((int) sleepTime));
        }
    }

    /**
     * Small test to ensure the class basically works.
     * @param args
     * @throws Exception
     */
    public static void main(final String[] args) throws Exception {
        RollingBatchRestartRsAction action = new RollingBatchRestartRsAction(1, 1.0f) {
            private int invocations = 0;

            @Override
            protected ServerName[] getCurrentServers() throws IOException {
                final int count = 4;
                List<ServerName> serverNames = new ArrayList<ServerName>(count);
                for (int i = 0; i < 4; i++) {
                    serverNames.add(ServerName.valueOf(i + ".example.org", i, i));
                }
                return serverNames.toArray(new ServerName[] {});
            }

            @Override
            protected void killRs(ServerName server) throws IOException {
                LOG.info("Killed " + server);
                if (this.invocations++ % 3 == 0) {
                    throw new org.apache.hadoop.util.Shell.ExitCodeException(-1, "Failed");
                }
            }

            @Override
            protected void startRs(ServerName server) throws IOException {
                LOG.info("Started " + server);
                if (this.invocations++ % 3 == 0) {
                    throw new org.apache.hadoop.util.Shell.ExitCodeException(-1, "Failed");
                }
            }
        };

        action.perform();
    }
}