Java tutorial
/** * * 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.master; import java.io.File; import java.io.IOException; import java.util.List; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.hbase.CoordinatedStateManager; import org.apache.hadoop.hbase.CoordinatedStateManagerFactory; import org.apache.hadoop.hbase.MasterNotRunningException; import org.apache.hadoop.hbase.ZNodeClearer; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.LocalHBaseCluster; import org.apache.hadoop.hbase.ZooKeeperConnectionException; import org.apache.hadoop.hbase.client.HBaseAdmin; import org.apache.hadoop.hbase.regionserver.HRegionServer; import org.apache.hadoop.hbase.util.JVMClusterUtil; import org.apache.hadoop.hbase.util.ServerCommandLine; import org.apache.hadoop.hbase.zookeeper.MiniZooKeeperCluster; import org.apache.hadoop.hbase.zookeeper.ZKUtil; import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem; import org.apache.zookeeper.KeeperException; @InterfaceAudience.Private public class HMasterCommandLine extends ServerCommandLine { private static final Log LOG = LogFactory.getLog(HMasterCommandLine.class); private static final String USAGE = "Usage: Master [opts] start|stop|clear\n" + " start Start Master. If local mode, start Master and RegionServer in same JVM\n" + " stop Start cluster shutdown; Master signals RegionServer shutdown\n" + " clear Delete the master znode in ZooKeeper after a master crashes\n " + " where [opts] are:\n" + " --minRegionServers=<servers> Minimum RegionServers needed to host user tables.\n" + " --localRegionServers=<servers> " + "RegionServers to start in master process when in standalone mode.\n" + " --masters=<servers> Masters to start in this process.\n" + " --backup Master should start in backup mode"; private final Class<? extends HMaster> masterClass; public HMasterCommandLine(Class<? extends HMaster> masterClass) { this.masterClass = masterClass; } protected String getUsage() { return USAGE; } public int run(String args[]) throws Exception { Options opt = new Options(); opt.addOption("localRegionServers", true, "RegionServers to start in master process when running standalone"); opt.addOption("masters", true, "Masters to start in this process"); opt.addOption("minRegionServers", true, "Minimum RegionServers needed to host user tables"); opt.addOption("backup", false, "Do not try to become HMaster until the primary fails"); CommandLine cmd; try { cmd = new GnuParser().parse(opt, args); } catch (ParseException e) { LOG.error("Could not parse: ", e); usage(null); return 1; } if (cmd.hasOption("minRegionServers")) { String val = cmd.getOptionValue("minRegionServers"); getConf().setInt("hbase.regions.server.count.min", Integer.valueOf(val)); LOG.debug("minRegionServers set to " + val); } // minRegionServers used to be minServers. Support it too. if (cmd.hasOption("minServers")) { String val = cmd.getOptionValue("minServers"); getConf().setInt("hbase.regions.server.count.min", Integer.valueOf(val)); LOG.debug("minServers set to " + val); } // check if we are the backup master - override the conf if so if (cmd.hasOption("backup")) { getConf().setBoolean(HConstants.MASTER_TYPE_BACKUP, true); } // How many regionservers to startup in this process (we run regionservers in same process as // master when we are in local/standalone mode. Useful testing) if (cmd.hasOption("localRegionServers")) { String val = cmd.getOptionValue("localRegionServers"); getConf().setInt("hbase.regionservers", Integer.valueOf(val)); LOG.debug("localRegionServers set to " + val); } // How many masters to startup inside this process; useful testing if (cmd.hasOption("masters")) { String val = cmd.getOptionValue("masters"); getConf().setInt("hbase.masters", Integer.valueOf(val)); LOG.debug("masters set to " + val); } @SuppressWarnings("unchecked") List<String> remainingArgs = cmd.getArgList(); if (remainingArgs.size() != 1) { usage(null); return 1; } String command = remainingArgs.get(0); if ("start".equals(command)) { return startMaster(); } else if ("stop".equals(command)) { return stopMaster(); } else if ("clear".equals(command)) { return (ZNodeClearer.clear(getConf()) ? 0 : 1); } else { usage("Invalid command: " + command); return 1; } } private int startMaster() { Configuration conf = getConf(); try { // If 'local', defer to LocalHBaseCluster instance. Starts master // and regionserver both in the one JVM. if (LocalHBaseCluster.isLocal(conf)) { DefaultMetricsSystem.setMiniClusterMode(true); conf.setInt(ServerManager.WAIT_ON_REGIONSERVERS_MINTOSTART, 1); final MiniZooKeeperCluster zooKeeperCluster = new MiniZooKeeperCluster(conf); File zkDataPath = new File(conf.get(HConstants.ZOOKEEPER_DATA_DIR)); int zkClientPort = conf.getInt(HConstants.ZOOKEEPER_CLIENT_PORT, 0); if (zkClientPort == 0) { throw new IOException("No config value for " + HConstants.ZOOKEEPER_CLIENT_PORT); } zooKeeperCluster.setDefaultClientPort(zkClientPort); // login the zookeeper server principal (if using security) ZKUtil.loginServer(conf, "hbase.zookeeper.server.keytab.file", "hbase.zookeeper.server.kerberos.principal", null); int clientPort = zooKeeperCluster.startup(zkDataPath); if (clientPort != zkClientPort) { String errorMsg = "Could not start ZK at requested port of " + zkClientPort + ". ZK was started at port: " + clientPort + ". Aborting as clients (e.g. shell) will not be able to find " + "this ZK quorum."; System.err.println(errorMsg); throw new IOException(errorMsg); } conf.set(HConstants.ZOOKEEPER_CLIENT_PORT, Integer.toString(clientPort)); conf.setInt(HConstants.ZK_SESSION_TIMEOUT, 10 * 1000); // Need to have the zk cluster shutdown when master is shutdown. // Run a subclass that does the zk cluster shutdown on its way out. LocalHBaseCluster cluster = new LocalHBaseCluster(conf, conf.getInt("hbase.masters", 1), conf.getInt("hbase.regionservers", 0), LocalHMaster.class, HRegionServer.class); ((LocalHMaster) cluster.getMaster(0)).setZKCluster(zooKeeperCluster); cluster.startup(); waitOnMasterThreads(cluster); } else { logProcessInfo(getConf()); CoordinatedStateManager csm = CoordinatedStateManagerFactory.getCoordinatedStateManager(conf); HMaster master = HMaster.constructMaster(masterClass, conf, csm); if (master.isStopped()) { LOG.info("Won't bring the Master up as a shutdown is requested"); return 1; } master.start(); master.join(); if (master.isAborted()) throw new RuntimeException("HMaster Aborted"); } } catch (Throwable t) { LOG.error("Master exiting", t); return 1; } return 0; } private int stopMaster() { HBaseAdmin adm = null; try { Configuration conf = getConf(); // Don't try more than once conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 1); adm = new HBaseAdmin(getConf()); } catch (MasterNotRunningException e) { LOG.error("Master not running"); return 1; } catch (ZooKeeperConnectionException e) { LOG.error("ZooKeeper not available"); return 1; } catch (IOException e) { LOG.error("Got IOException: " + e.getMessage(), e); return 1; } try { adm.shutdown(); } catch (Throwable t) { LOG.error("Failed to stop master", t); return 1; } return 0; } private void waitOnMasterThreads(LocalHBaseCluster cluster) throws InterruptedException { List<JVMClusterUtil.MasterThread> masters = cluster.getMasters(); List<JVMClusterUtil.RegionServerThread> regionservers = cluster.getRegionServers(); if (masters != null) { for (JVMClusterUtil.MasterThread t : masters) { t.join(); if (t.getMaster().isAborted()) { closeAllRegionServerThreads(regionservers); throw new RuntimeException("HMaster Aborted"); } } } } private static void closeAllRegionServerThreads(List<JVMClusterUtil.RegionServerThread> regionservers) { for (JVMClusterUtil.RegionServerThread t : regionservers) { t.getRegionServer().stop("HMaster Aborted; Bringing down regions servers"); } } /* * Version of master that will shutdown the passed zk cluster on its way out. */ public static class LocalHMaster extends HMaster { private MiniZooKeeperCluster zkcluster = null; public LocalHMaster(Configuration conf, CoordinatedStateManager csm) throws IOException, KeeperException, InterruptedException { super(conf, csm); } @Override public void run() { super.run(); if (this.zkcluster != null) { try { this.zkcluster.shutdown(); } catch (IOException e) { e.printStackTrace(); } } } void setZKCluster(final MiniZooKeeperCluster zkcluster) { this.zkcluster = zkcluster; } } }