hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/safemode/DataNodeSafeModeRule.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.hdds.scm.safemode;

import java.util.HashSet;
import java.util.UUID;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdds.HddsConfigKeys;
import org.apache.hadoop.hdds.scm.events.SCMEvents;
import org.apache.hadoop.hdds.scm.server.SCMDatanodeProtocolServer.NodeRegistrationContainerReport;

import org.apache.hadoop.hdds.server.events.EventQueue;
import org.apache.hadoop.hdds.server.events.TypedEvent;

/**
 * Class defining Safe mode exit criteria according to number of DataNodes
 * registered with SCM.
 */
public class DataNodeSafeModeRule extends
    SafeModeExitRule<NodeRegistrationContainerReport>{

  // Min DataNodes required to exit safe mode.
  private int requiredDns;
  private int registeredDns = 0;
  // Set to track registered DataNodes.
  private HashSet<UUID> registeredDnSet;

  public DataNodeSafeModeRule(String ruleName, EventQueue eventQueue,
      Configuration conf,
      SCMSafeModeManager manager) {
    super(manager, ruleName, eventQueue);
    requiredDns = conf.getInt(
        HddsConfigKeys.HDDS_SCM_SAFEMODE_MIN_DATANODE,
        HddsConfigKeys.HDDS_SCM_SAFEMODE_MIN_DATANODE_DEFAULT);
    registeredDnSet = new HashSet<>(requiredDns * 2);
  }

  @Override
  protected TypedEvent<NodeRegistrationContainerReport> getEventType() {
    return SCMEvents.NODE_REGISTRATION_CONT_REPORT;
  }

  @Override
  protected boolean validate() {
    return registeredDns >= requiredDns;
  }

  @Override
  protected void process(NodeRegistrationContainerReport reportsProto) {

    registeredDnSet.add(reportsProto.getDatanodeDetails().getUuid());
    registeredDns = registeredDnSet.size();

    if (scmInSafeMode()) {
      SCMSafeModeManager.getLogger().info(
          "SCM in safe mode. {} DataNodes registered, {} required.",
          registeredDns, requiredDns);
    }

  }

  @Override
  protected void cleanup() {
    registeredDnSet.clear();
  }
}