client/mapreduce/src/main/java/org/apache/accumulo/core/client/mapreduce/lib/impl/MapReduceClientOpts.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.accumulo.core.client.mapreduce.lib.impl;

import org.apache.accumulo.core.cli.ClientOpts;
import org.apache.accumulo.core.client.Accumulo;
import org.apache.accumulo.core.client.AccumuloClient;
import org.apache.accumulo.core.client.AccumuloSecurityException;
import org.apache.accumulo.core.client.admin.DelegationTokenConfig;
import org.apache.accumulo.core.client.mapreduce.AccumuloInputFormat;
import org.apache.accumulo.core.client.mapreduce.AccumuloOutputFormat;
import org.apache.accumulo.core.client.security.tokens.AuthenticationToken;
import org.apache.accumulo.core.client.security.tokens.KerberosToken;
import org.apache.accumulo.core.security.SystemPermission;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.security.UserGroupInformation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Adds some MR awareness to the ClientOpts
 */
public class MapReduceClientOpts extends ClientOpts {
  private static final Logger log = LoggerFactory.getLogger(MapReduceClientOpts.class);

  public void setAccumuloConfigs(Job job) throws AccumuloSecurityException {
    AccumuloInputFormat.setClientInfo(job, this.getClientInfo());
    AccumuloOutputFormat.setClientInfo(job, this.getClientInfo());
  }

  @Override
  public AuthenticationToken getToken() {
    AuthenticationToken authToken = super.getToken();
    // For MapReduce, Kerberos credentials don't make it to the Mappers and Reducers,
    // so we need to request a delegation token and use that instead.
    if (authToken instanceof KerberosToken) {
      log.info("Received KerberosToken, fetching DelegationToken for MapReduce");
      final KerberosToken krbToken = (KerberosToken) authToken;

      try {
        UserGroupInformation user = UserGroupInformation.getCurrentUser();
        if (!user.hasKerberosCredentials()) {
          throw new IllegalStateException("Expected current user to have Kerberos credentials");
        }

        String newPrincipal = user.getUserName();
        log.info("Obtaining delegation token for {}", newPrincipal);

        setPrincipal(newPrincipal);
        AccumuloClient client = Accumulo.newClient().usingClientInfo(getClientInfo())
            .usingToken(newPrincipal, krbToken).build();

        // Do the explicit check to see if the user has the permission to get a delegation token
        if (!client.securityOperations().hasSystemPermission(client.whoami(),
            SystemPermission.OBTAIN_DELEGATION_TOKEN)) {
          log.error(
              "{} doesn't have the {} SystemPermission neccesary to obtain a delegation"
                  + " token. MapReduce tasks cannot automatically use the client's"
                  + " credentials on remote servers. Delegation tokens provide a means to run"
                  + " MapReduce without distributing the user's credentials.",
              user.getUserName(), SystemPermission.OBTAIN_DELEGATION_TOKEN.name());
          throw new IllegalStateException(
              client.whoami() + " does not have permission to obtain a delegation token");
        }

        // Get the delegation token from Accumulo
        return client.securityOperations().getDelegationToken(new DelegationTokenConfig());
      } catch (Exception e) {
        final String msg = "Failed to acquire DelegationToken for use with MapReduce";
        log.error(msg, e);
        throw new RuntimeException(msg, e);
      }
    }
    return authToken;
  }
}