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 javax.inject.Inject;
  
  
  import com.cloud.agent.AgentManager;
  import com.cloud.agent.api.CheckVirtualMachineAnswer;
  import com.cloud.agent.api.CheckVirtualMachineCommand;
  import com.cloud.exception.AgentUnavailableException;
  import com.cloud.exception.OperationTimedoutException;
  import com.cloud.host.Host;
  import com.cloud.host.Status;
  import com.cloud.utils.component.AdapterBase;
  import com.cloud.vm.VirtualMachine;
  import com.cloud.vm.VirtualMachine.PowerState;
  
  public class CheckOnAgentInvestigator extends AdapterBase implements Investigator {
      @Inject
      AgentManager _agentMgr;
  
      protected CheckOnAgentInvestigator() {
      }
  
      @Override
      public Status isAgentAlive(Host agent) {
          return null;
      }
  
      @Override
      public boolean isVmAlive(VirtualMachine vm, Host host) throws UnknownVM {
          CheckVirtualMachineCommand cmd = new CheckVirtualMachineCommand(vm.getInstanceName());
          try {
              CheckVirtualMachineAnswer answer = (CheckVirtualMachineAnswer)_agentMgr.send(vm.getHostId(), cmd);
              if (!answer.getResult()) {
                  logger.debug("Unable to get vm state on " + vm.toString());
                  throw new UnknownVM();
              }
  
              logger.debug("Agent responded with state " + answer.getState().toString());
              return answer.getState() == PowerState.PowerOn;
          } catch (AgentUnavailableException e) {
              logger.debug("Unable to reach the agent for " + vm.toString() + ": " + e.getMessage());
              throw new UnknownVM();
          } catch (OperationTimedoutException e) {
              logger.debug("Operation timed out for " + vm.toString() + ": " + e.getMessage());
              throw new UnknownVM();
          }
      }
  }
  