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 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;
  
  import org.apache.cloudstack.engine.subsystem.api.storage.DataStoreDriver;
  import org.apache.cloudstack.engine.subsystem.api.storage.DataStoreProvider;
  import org.apache.cloudstack.engine.subsystem.api.storage.DataStoreProviderManager;
  import org.apache.cloudstack.engine.subsystem.api.storage.PrimaryDataStoreDriver;
  import org.apache.cloudstack.ha.HAManager;
  import org.apache.cloudstack.storage.datastore.db.PrimaryDataStoreDao;
  import org.apache.cloudstack.storage.datastore.db.StoragePoolVO;
  
  import javax.inject.Inject;
  import java.util.Arrays;
  import java.util.List;
  
  public class KVMInvestigator extends AdapterBase implements Investigator {
      @Inject
      private HostDao _hostDao;
      @Inject
      private AgentManager _agentMgr;
      @Inject
      private ResourceManager _resourceMgr;
      @Inject
      private PrimaryDataStoreDao _storagePoolDao;
      @Inject
      private HAManager haManager;
      @Inject
      private DataStoreProviderManager dataStoreProviderMgr;
  
      @Override
      public boolean isVmAlive(com.cloud.vm.VirtualMachine vm, Host host) throws UnknownVM {
          if (haManager.isHAEligible(host)) {
              return haManager.isVMAliveOnHost(host);
          }
          Status status = isAgentAlive(host);
          logger.debug("HA: HOST is ineligible legacy state {} for host {}", status, host);
          if (status == null) {
              throw new UnknownVM();
          }
          if (status == Status.Up) {
              return true;
          } else {
              throw new UnknownVM();
          }
      }
  
      @Override
      public Status isAgentAlive(Host agent) {
          if (agent.getHypervisorType() != Hypervisor.HypervisorType.KVM && agent.getHypervisorType() != Hypervisor.HypervisorType.LXC) {
              return null;
          }
  
          if (haManager.isHAEligible(agent)) {
              return haManager.getHostStatus(agent);
          }
  
          List<StoragePoolVO> clusterPools = _storagePoolDao.findPoolsInClusters(Arrays.asList(agent.getClusterId()), null);
          boolean storageSupportHA = storageSupportHa(clusterPools);
          if (!storageSupportHA) {
              List<StoragePoolVO> zonePools = _storagePoolDao.findZoneWideStoragePoolsByHypervisor(agent.getDataCenterId(), agent.getHypervisorType());
              storageSupportHA = storageSupportHa(zonePools);
          }
          if (!storageSupportHA) {
              logger.warn("Agent investigation was requested on host {}, but host does not support investigation because it has no NFS storage. Skipping investigation.", agent);
              return null;
          }
  
          Status hostStatus = null;
          Status neighbourStatus = null;
          boolean reportFailureIfOneStorageIsDown = HighAvailabilityManager.KvmHAFenceHostIfHeartbeatFailsOnStorage.value();
          CheckOnHostCommand cmd = new CheckOnHostCommand(agent, reportFailureIfOneStorageIsDown);
  
          try {
              Answer answer = _agentMgr.easySend(agent.getId(), cmd);
              if (answer != null) {
                  hostStatus = answer.getResult() ? Status.Down : Status.Up;
              }
          } catch (Exception e) {
              logger.debug("Failed to send command to host: {}", agent);
          }
          if (hostStatus == null) {
              hostStatus = Status.Disconnected;
          }
  
          List<HostVO> neighbors = _resourceMgr.listHostsInClusterByStatus(agent.getClusterId(), Status.Up);
          for (HostVO neighbor : neighbors) {
              if (neighbor.getId() == agent.getId()
                      || (neighbor.getHypervisorType() != Hypervisor.HypervisorType.KVM && neighbor.getHypervisorType() != Hypervisor.HypervisorType.LXC)) {
                  continue;
              }
              logger.debug("Investigating host:{} via neighbouring host:{}", agent, neighbor);
              try {
                  Answer answer = _agentMgr.easySend(neighbor.getId(), cmd);
                  if (answer != null) {
                      neighbourStatus = answer.getResult() ? Status.Down : Status.Up;
                      logger.debug("Neighbouring host:{} returned status:{} for the investigated host:{}", neighbor, neighbourStatus, agent);
                      if (neighbourStatus == Status.Up) {
                          break;
                      }
                  }
              } catch (Exception e) {
                  logger.debug("Failed to send command to host: {}", neighbor);
              }
          }
          if (neighbourStatus == Status.Up && (hostStatus == Status.Disconnected || hostStatus == Status.Down)) {
              hostStatus = Status.Disconnected;
          }
          if (neighbourStatus == Status.Down && (hostStatus == Status.Disconnected || hostStatus == Status.Down)) {
              hostStatus = Status.Down;
          }
          logger.debug("HA: HOST is ineligible legacy state {} for host {}", hostStatus, agent);
          return hostStatus;
      }
  
      private boolean storageSupportHa(List<StoragePoolVO> pools) {
          boolean storageSupportHA = false;
          for (StoragePoolVO pool : pools) {
              DataStoreProvider storeProvider = dataStoreProviderMgr.getDataStoreProvider(pool.getStorageProviderName());
              DataStoreDriver storeDriver = storeProvider.getDataStoreDriver();
              if (storeDriver instanceof PrimaryDataStoreDriver) {
                  PrimaryDataStoreDriver primaryStoreDriver = (PrimaryDataStoreDriver)storeDriver;
                  if (primaryStoreDriver.isStorageSupportHA(pool.getPoolType())) {
                      storageSupportHA = true;
                      break;
                  }
              }
          }
          return storageSupportHA;
      }
  }
  