hadoop SshFenceByTcpPort 源码

  • 2022-10-20
  • 浏览 (486)

haddop SshFenceByTcpPort 代码

文件路径:/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/SshFenceByTcpPort.java

/**
 * 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.ha;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Collection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.hadoop.conf.Configured;

import org.apache.hadoop.classification.VisibleForTesting;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This fencing implementation sshes to the target node and uses 
 * <code>fuser</code> to kill the process listening on the service's
 * TCP port. This is more accurate than using "jps" since it doesn't 
 * require parsing, and will work even if there are multiple service
 * processes running on the same machine.<p>
 * It returns a successful status code if:
 * <ul>
 * <li><code>fuser</code> indicates it successfully killed a process, <em>or</em>
 * <li><code>nc -z</code> indicates that nothing is listening on the target port
 * </ul>
 * <p>
 * This fencing mechanism is configured as following in the fencing method
 * list:
 * <code>sshfence([[username][:ssh-port]])</code>
 * where the optional argument specifies the username and port to use
 * with ssh.
 * <p>
 * In order to achieve passwordless SSH, the operator must also configure
 * <code>dfs.ha.fencing.ssh.private-key-files</code> to point to an
 * SSH key that has passphrase-less access to the given username and host.
 */
public class SshFenceByTcpPort extends Configured
  implements FenceMethod {

  static final Logger LOG = LoggerFactory.getLogger(SshFenceByTcpPort.class);

  static final String CONF_CONNECT_TIMEOUT_KEY =
    "dfs.ha.fencing.ssh.connect-timeout";
  private static final int CONF_CONNECT_TIMEOUT_DEFAULT =
    30*1000;
  static final String CONF_IDENTITIES_KEY =
    "dfs.ha.fencing.ssh.private-key-files";

  /**
   * Verify that the argument, if given, in the conf is parseable.
   */
  @Override
  public void checkArgs(String argStr) throws BadFencingConfigurationException {
    if (argStr != null) {
      new Args(argStr);
    }
  }

  @Override
  public boolean tryFence(HAServiceTarget target, String argsStr)
      throws BadFencingConfigurationException {

    Args args = new Args(argsStr);
    InetSocketAddress serviceAddr = target.getAddress();
    String host = serviceAddr.getHostName();
    
    Session session;
    try {
      session = createSession(serviceAddr.getHostName(), args);
    } catch (JSchException e) {
      LOG.warn("Unable to create SSH session", e);
      return false;
    }

    LOG.info("Connecting to " + host + "...");
    
    try {
      session.connect(getSshConnectTimeout());
    } catch (JSchException e) {
      LOG.warn("Unable to connect to " + host
          + " as user " + args.user, e);
      return false;
    }
    LOG.info("Connected to " + host);

    try {
      return doFence(session, serviceAddr);
    } catch (JSchException e) {
      LOG.warn("Unable to achieve fencing on remote host", e);
      return false;
    } finally {
      session.disconnect();
    }
  }


  private Session createSession(String host, Args args) throws JSchException {
    JSch jsch = new JSch();
    for (String keyFile : getKeyFiles()) {
      jsch.addIdentity(keyFile);
    }
    JSch.setLogger(new LogAdapter());

    Session session = jsch.getSession(args.user, host, args.sshPort);
    session.setConfig("StrictHostKeyChecking", "no");
    return session;
  }

  private boolean doFence(Session session, InetSocketAddress serviceAddr)
      throws JSchException {
    int port = serviceAddr.getPort();
    try {
      LOG.info("Looking for process running on port " + port);
      int rc = execCommand(session,
          "PATH=$PATH:/sbin:/usr/sbin fuser -v -k -n tcp " + port);
      if (rc == 0) {
        LOG.info("Successfully killed process that was " +
            "listening on port " + port);
        // exit code 0 indicates the process was successfully killed.
        return true;
      } else if (rc == 1) {
        // exit code 1 indicates either that the process was not running
        // or that fuser didn't have root privileges in order to find it
        // (eg running as a different user)
        LOG.info(
            "Indeterminate response from trying to kill service. " +
            "Verifying whether it is running using nc...");
        rc = execCommand(session, "nc -z " + serviceAddr.getHostName() +
            " " + serviceAddr.getPort());
        if (rc == 0) {
          // the service is still listening - we are unable to fence
          LOG.warn("Unable to fence - it is running but we cannot kill it");
          return false;
        } else {
          LOG.info("Verified that the service is down.");
          return true;          
        }
      } else {
        // other 
      }
      LOG.info("rc: " + rc);
      return rc == 0;
    } catch (InterruptedException e) {
      LOG.warn("Interrupted while trying to fence via ssh", e);
      return false;
    } catch (IOException e) {
      LOG.warn("Unknown failure while trying to fence via ssh", e);
      return false;
    }
  }
  
  /**
   * Execute a command through the ssh session, pumping its
   * stderr and stdout to our own logs.
   */
  private int execCommand(Session session, String cmd)
      throws JSchException, InterruptedException, IOException {
    LOG.debug("Running cmd: " + cmd);
    ChannelExec exec = null;
    try {
      exec = (ChannelExec)session.openChannel("exec");
      exec.setCommand(cmd);
      exec.setInputStream(null);
      exec.connect();

      // Pump stdout of the command to our WARN logs
      StreamPumper outPumper = new StreamPumper(LOG, cmd + " via ssh",
          exec.getInputStream(), StreamPumper.StreamType.STDOUT);
      outPumper.start();
      
      // Pump stderr of the command to our WARN logs
      StreamPumper errPumper = new StreamPumper(LOG, cmd + " via ssh",
          exec.getErrStream(), StreamPumper.StreamType.STDERR);
      errPumper.start();
      
      outPumper.join();
      errPumper.join();
      return exec.getExitStatus();
    } finally {
      cleanup(exec);
    }
  }

  private static void cleanup(ChannelExec exec) {
    if (exec != null) {
      try {
        exec.disconnect();
      } catch (Throwable t) {
        LOG.warn("Couldn't disconnect ssh channel", t);
      }
    }
  }

  private int getSshConnectTimeout() {
    return getConf().getInt(
        CONF_CONNECT_TIMEOUT_KEY, CONF_CONNECT_TIMEOUT_DEFAULT);
  }

  private Collection<String> getKeyFiles() {
    return getConf().getTrimmedStringCollection(CONF_IDENTITIES_KEY);
  }
  
  /**
   * Container for the parsed arg line for this fencing method.
   */
  @VisibleForTesting
  static class Args {
    private static final Pattern USER_PORT_RE = Pattern.compile(
      "([^:]+?)?(?:\\:(\\d+))?");

    private static final int DEFAULT_SSH_PORT = 22;

    String user;
    int sshPort;
    
    public Args(String arg) 
        throws BadFencingConfigurationException {
      user = System.getProperty("user.name");
      sshPort = DEFAULT_SSH_PORT;

      // Parse optional user and ssh port
      if (arg != null && !arg.isEmpty()) {
        Matcher m = USER_PORT_RE.matcher(arg);
        if (!m.matches()) {
          throw new BadFencingConfigurationException(
              "Unable to parse user and SSH port: "+ arg);
        }
        if (m.group(1) != null) {
          user = m.group(1);
        }
        if (m.group(2) != null) {
          sshPort = parseConfiggedPort(m.group(2));
        }
      }
    }

    private int parseConfiggedPort(String portStr)
        throws BadFencingConfigurationException {
      try {
        return Integer.parseInt(portStr);
      } catch (NumberFormatException nfe) {
        throw new BadFencingConfigurationException(
            "Port number '" + portStr + "' invalid");
      }
    }
  }

  /**
   * Adapter from JSch's logger interface to our log4j
   */
  private static class LogAdapter implements com.jcraft.jsch.Logger {
    static final Logger LOG = LoggerFactory.getLogger(
        SshFenceByTcpPort.class.getName() + ".jsch");

    @Override
    public boolean isEnabled(int level) {
      switch (level) {
      case com.jcraft.jsch.Logger.DEBUG:
        return LOG.isDebugEnabled();
      case com.jcraft.jsch.Logger.INFO:
        return LOG.isInfoEnabled();
      case com.jcraft.jsch.Logger.WARN:
        return LOG.isWarnEnabled();
      case com.jcraft.jsch.Logger.ERROR:
      case com.jcraft.jsch.Logger.FATAL:
        return LOG.isErrorEnabled();
      default:
        return false;
      }
    }
      
    @Override
    public void log(int level, String message) {
      switch (level) {
      case com.jcraft.jsch.Logger.DEBUG:
        LOG.debug(message);
        break;
      case com.jcraft.jsch.Logger.INFO:
        LOG.info(message);
        break;
      case com.jcraft.jsch.Logger.WARN:
        LOG.warn(message);
        break;
      case com.jcraft.jsch.Logger.ERROR:
      case com.jcraft.jsch.Logger.FATAL:
        LOG.error(message);
        break;
      default:
        break;
      }
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop ActiveStandbyElector 源码

hadoop BadFencingConfigurationException 源码

hadoop FailoverController 源码

hadoop FailoverFailedException 源码

hadoop FenceMethod 源码

hadoop HAAdmin 源码

hadoop HAServiceProtocol 源码

hadoop HAServiceProtocolHelper 源码

hadoop HAServiceStatus 源码

hadoop HAServiceTarget 源码

0  赞