public boolean createManager() {
    synchronized (instances) {
      if (federatingManager != null) {
        return false;
      }
      system.handleResourceEvent(ResourceEvent.MANAGER_CREATE, null);
      // An initialised copy of federating manager
      federatingManager = federatingManagerFactory.create(repo, system, this, cache,
          statisticsFactory, statisticsClock, new MBeanProxyFactory(jmxAdapter, this),
          new MemberMessenger(jmxAdapter, system),
          () -> LoggingExecutors.newFixedThreadPool(Runtime.getRuntime().availableProcessors(),
              "FederatingManager", true));
      cache.getJmxManagerAdvisor().broadcastChange();
      return true;
    }
  }
Creates a Manager instance in stopped state.
geode-core/src/main/java/org/apache/geode/management/internal/SystemManagementService.java