public void stop()

in hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/server/StorageContainerManager.java [1597:1740]
120 lines of code
25 McCabe index (conditional complexity)

  public void stop() {
    if (isStopped.getAndSet(true)) {
      LOG.info("Storage Container Manager is not running.");
      IOUtils.close(LOG, scmHAManager);
      stopReplicationManager(); // started eagerly
      return;
    }
    try {
      if (containerBalancer.isBalancerRunning()) {
        LOG.info("Stopping Container Balancer service.");
        // stop ContainerBalancer thread in this scm
        containerBalancer.stop();
      } else {
        LOG.info("Container Balancer is not running.");
      }
    } catch (Exception e) {
      LOG.error("Failed to stop Container Balancer service.", e);
    }

    stopReplicationManager();

    try {
      LOG.info("Stopping the Datanode Admin Monitor.");
      scmDecommissionManager.stop();
    } catch (Exception ex) {
      LOG.error("The Datanode Admin Monitor failed to stop", ex);
    }

    try {
      LOG.info("Stopping datanode service RPC server");
      getDatanodeProtocolServer().stop();

    } catch (Exception ex) {
      LOG.error("Storage Container Manager datanode RPC stop failed.", ex);
    }

    try {
      LOG.info("Stopping block service RPC server");
      getBlockProtocolServer().stop();
    } catch (Exception ex) {
      LOG.error("Storage Container Manager blockRpcServer stop failed.", ex);
    }

    try {
      LOG.info("Stopping the StorageContainerLocationProtocol RPC server");
      getClientProtocolServer().stop();
    } catch (Exception ex) {
      LOG.error("Storage Container Manager clientRpcServer stop failed.", ex);
    }

    try {
      LOG.info("Stopping Storage Container Manager HTTP server.");
      if (httpServer != null) {
        httpServer.stop();
      }
    } catch (Exception ex) {
      LOG.error("Storage Container Manager HTTP server stop failed.", ex);
    }

    LOG.info("Stopping SCM LayoutVersionManager Service.");
    scmLayoutVersionManager.close();

    if (getSecurityProtocolServer() != null) {
      getSecurityProtocolServer().stop();
    }

    if (rootCARotationManager != null) {
      rootCARotationManager.stop();
    }

    try {
      LOG.info("Stopping Block Manager Service.");
      scmBlockManager.stop();
    } catch (Exception ex) {
      LOG.error("SCM block manager service stop failed.", ex);
    }

    if (metrics != null) {
      metrics.unRegister();
    }

    nettyMetrics.unregister();
    if (perfMetrics != null) {
      perfMetrics.unRegister();
    }

    unregisterMXBean();
    if (scmContainerMetrics != null) {
      scmContainerMetrics.unRegister();
    }
    if (placementMetrics != null) {
      placementMetrics.unRegister();
    }

    // Event queue must be stopped before the DB store is closed at the end.
    try {
      LOG.info("Stopping SCM Event Queue.");
      eventQueue.close();
    } catch (Exception ex) {
      LOG.error("SCM Event Queue stop failed", ex);
    }

    try {
      LOG.info("Stopping SCM HA services.");
      scmHAManager.stop();
    } catch (Exception ex) {
      LOG.error("SCM HA Manager stop failed", ex);
    }

    if (scmHAMetrics != null) {
      SCMHAMetrics.unRegister();
    }

    IOUtils.cleanupWithLogger(LOG, containerManager);
    IOUtils.cleanupWithLogger(LOG, pipelineManager);

    if (ms != null) {
      ms.stop();
    }

    scmSafeModeManager.stop();
    serviceManager.stop();
    try {
      leaseManager.shutdown();
    } catch (LeaseManagerNotRunningException ex) {
      LOG.debug("Lease manager not running, ignore");
    }
    RatisDropwizardExports.clear(ratisMetricsMap, ratisReporterList);

    if (scmCertificateClient != null) {
      try {
        scmCertificateClient.close();
      } catch (IOException ioe) {
        LOG.error("Closing certificate client failed", ioe);
      }
    }

    try {
      LOG.info("Stopping SCM MetadataStore.");
      scmMetadataStore.stop();
    } catch (Exception ex) {
      LOG.error("SCM Metadata store stop failed", ex);
    }
  }