content: // 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 com.cloud.ha;
  
  import java.util.List;
  
  import javax.inject.Inject;
  
  
  import com.cloud.agent.AgentManager;
  import com.cloud.agent.api.Answer;
  import com.cloud.agent.api.CheckOnHostCommand;
  import com.cloud.host.Host;
  import com.cloud.host.HostVO;
  import com.cloud.host.Status;
  import com.cloud.host.dao.HostDao;
  import com.cloud.hypervisor.Hypervisor;
  import com.cloud.resource.ResourceManager;
  import com.cloud.utils.component.AdapterBase;
  
  public class Ovm3Investigator extends AdapterBase implements Investigator {
      @Inject
      HostDao hostDao;
      @Inject
      AgentManager agentMgr;
      @Inject
      ResourceManager resourceMgr;
  
      @Override
      public boolean isVmAlive(com.cloud.vm.VirtualMachine vm, Host host) throws UnknownVM {
          logger.debug("isVmAlive: " + vm.getHostName() + " on " + host.getName());
          if (host.getHypervisorType() != Hypervisor.HypervisorType.Ovm3) {
              throw new UnknownVM();
          }
          Status status = isAgentAlive(host);
          if (status == null) {
              return false;
          }
          return status == Status.Up ? true : false;
      }
  
      @Override
      public Status isAgentAlive(Host agent) {
          logger.debug("isAgentAlive: " + agent.getName());
          if (agent.getHypervisorType() != Hypervisor.HypervisorType.Ovm3) {
              return null;
          }
          CheckOnHostCommand cmd = new CheckOnHostCommand(agent);
          List<HostVO> neighbors = resourceMgr.listHostsInClusterByStatus(agent.getClusterId(), Status.Up);
          for (HostVO neighbor : neighbors) {
              if (neighbor.getId() == agent.getId() || neighbor.getHypervisorType() != Hypervisor.HypervisorType.Ovm3) {
                  continue;
              }
              try {
                  Answer answer = agentMgr.easySend(neighbor.getId(), cmd);
                  if (answer != null) {
                      return answer.getResult() ? Status.Down : Status.Up;
                  }
              } catch (Exception e) {
                  logger.error("Failed to send command to host: " + neighbor.getId(), e);
              }
          }
  
          return null;
      }
  }
  